The inclusive jet cross section is measured as a function of jet transverse momentum $p_\mathrm{T}$ and rapidity $y$. The measurement is performed using proton-proton collision data at $\sqrt{s}$ = 5.02 TeV, recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of 27.4 pb$^{-1}$. The jets are reconstructed with the anti-$k_\mathrm{T}$ algorithm using a distance parameter of $R$ = 0.4, within the rapidity interval $\lvert y\rvert$$\lt$ 2, and across the kinematic range 0.06 $\lt$$p_\mathrm{T}$$\lt$ 1 TeV. The jet cross section is unfolded from detector to particle level using the determined jet response and resolution. The results are compared to predictions of perturbative quantum chromodynamics, calculated at both next-to-leading order and next-to-next-to-leading order. The predictions are corrected for nonperturbative effects, and presented for a variety of parton distribution functions and choices of the renormalization/factorization scales and the strong coupling $\alpha_\mathrm{S}$.
The JEC, JER, and total systematic uncertainties in unfolded cross sections as functions of transverse momentum, for |y|<0.5. The total systematic uncertainty includes also the luminosity, jet identification and trigger efficiency uncertainties.
The JEC, JER, and total systematic uncertainties in unfolded cross sections as functions of transverse momentum, for 0.5<|y|<1. The total systematic uncertainty includes also the luminosity, jet identification and trigger efficiency uncertainties.
The JEC, JER, and total systematic uncertainties in unfolded cross sections as functions of transverse momentum, for 1<|y|<1.5. The total systematic uncertainty includes also the luminosity, jet identification and trigger efficiency uncertainties.
Measurements of the charge-dependent two-particle angular correlation function in proton-lead (pPb) collisions at a nucleon-nucleon center-of-mass energy of $\sqrt{s_\mathrm{NN}}$ = 8.16 TeV and lead-lead (PbPb) collisions at$\sqrt{s_\mathrm{NN}}$ = 5.02 TeV are reported. The pPb and PbPb datasets correspond to integrated luminosities of 186\nbinv and 0.607 nb$^{-1}$, respectively, and were collected using the CMS detector at the CERN LHC. The charge-dependent correlations are characterized by balance functions of same- and opposite-sign particle pairs. The balance functions, which contain information about the creation time of charged particle pairs and the development of collectivity, are studied as functions of relative pseudorapidity ($\Delta \eta$) and relative azimuthal angle ($\Delta \phi$), for various multiplicity and transverse momentum ($p_\mathrm{T}$) intervals. A multiplicity dependence of the balance function is observed in $\Delta \eta$ and $\Delta \phi$ for both systems. The width of the balance functions decreases towards high-multiplicity collisions in the momentum region $\lt$2 GeV, for pPb and PbPb results. No multiplicity dependence is observed at higher transverse momentum. The data are compared with HYDJET, HIJING and AMPT generator predictions, none of which capture completely the multiplicity dependence seen in the data.
$\Delta\eta$ projection of balance function in low $p_{T}$ in 0-10% centrality
$\Delta\eta$ projection of balance function in low $p_{T}$ in 30-40% centrality
$\Delta\eta$ projection of balance function in low $p_{T}$ in 70-80% centrality
The observation of the production of four top quarks in proton-proton collisions is reported, based on a data sample collected by the CMS experiment at a center-of-mass energy of 13 TeV in 2016-2018 at the CERN LHC and corresponding to an integrated luminosity of 138 fb$^{-1}$. Events with two same-sign, three, or four charged leptons (electrons and muons) and additional jets are analyzed. Compared to previous results in these channels, updated identification techniques for charged leptons and jets originating from the hadronization of b quarks, as well as a revised multivariate analysis strategy to distinguish the signal process from the main backgrounds, lead to an improved expected signal significance of 4.9 standard deviations above the background-only hypothesis. Four top quark production is observed with a significance of 5.6 standard deviations, and its cross section is measured to be 17.7 $^{+3.7}_{-3.5}$ (stat) $^{+2.3}_{-1.9}$ (syst) fb, in agreement with the available standard model predictions.
Comparison of fit results in the channels individually and in their combination. The left panel shows the values of the measured cross section relative to the SM prediction from Ref. [6]. The right panel shows the expected and observed significance, with the printed values rounded to the first decimal.
Number of predicted and observed events in the SR-2$\ell$ and SR-3$\ell$ $t\bar{t}t\bar{t}$ classes, both before the fit to the data ("prefit") and with their best fit normalizations ("postfit"). The uncertainties in the predicted number of events include both the statistical and systematic components. The uncertainties in the total number of predicted background and background plus signal events are also given.
This paper presents measurements of charged-hadron spectra obtained in $pp$, $p$+Pb, and Pb+Pb collisions at $\sqrt{s}$ or $\sqrt{s_{_\text{NN}}}=5.02$ TeV, and in Xe+Xe collisions at $\sqrt{s_{_\text{NN}}}=5.44$ TeV. The data recorded by the ATLAS detector at the LHC have total integrated luminosities of 25 pb${}^{-1}$, 28 nb${}^{-1}$, 0.50 nb${}^{-1}$, and 3 $\mu$b${}^{-1}$, respectively. The nuclear modification factors $R_{p\text{Pb}}$ and $R_\text{AA}$ are obtained by comparing the spectra in heavy-ion and $pp$ collisions in a wide range of charged-particle transverse momenta and pseudorapidity. The nuclear modification factor $R_{p\text{Pb}}$ shows a moderate enhancement above unity with a maximum at $p_{\mathrm{T}} \approx 3$ GeV; the enhancement is stronger in the Pb-going direction. The nuclear modification factors in both Pb+Pb and Xe+Xe collisions feature a significant, centrality-dependent suppression. They show a similar distinct $p_{\mathrm{T}}$-dependence with a local maximum at $p_{\mathrm{T}} \approx 2$ GeV and a local minimum at $p_{\mathrm{T}} \approx 7$ GeV. This dependence is more distinguishable in more central collisions. No significant $|\eta|$-dependence is found. A comprehensive comparison with several theoretical predictions is also provided. They typically describe $R_\text{AA}$ better in central collisions and in the $p_{\mathrm{T}}$ range from about 10 to 100 GeV.
- - - - - - - - - - - - - - - - - - - - <br><b>charged-hadron spectra:</b> <br><i>pp reference:</i> <a href="?version=1&table=Table1">for p+Pb</a> <a href="?version=1&table=Table10">for Pb+Pb</a> <a href="?version=1&table=Table19">for Xe+Xe</a> <br><i>p+Pb:</i> <a href="?version=1&table=Table2">0-5%</a> <a href="?version=1&table=Table3">5-10%</a> <a href="?version=1&table=Table4">10-20%</a> <a href="?version=1&table=Table5">20-30%</a> <a href="?version=1&table=Table6">30-40%</a> <a href="?version=1&table=Table7">40-60%</a> <a href="?version=1&table=Table8">60-90%</a> <a href="?version=1&table=Table9">0-90%</a> <br><i>Pb+Pb:</i> <a href="?version=1&table=Table11">0-5%</a> <a href="?version=1&table=Table12">5-10%</a> <a href="?version=1&table=Table13">10-20%</a> <a href="?version=1&table=Table14">20-30%</a> <a href="?version=1&table=Table15">30-40%</a> <a href="?version=1&table=Table16">40-50%</a> <a href="?version=1&table=Table17">50-60%</a> <a href="?version=1&table=Table18">60-80%</a> <br><i>Xe+Xe:</i> <a href="?version=1&table=Table20">0-5%</a> <a href="?version=1&table=Table21">5-10%</a> <a href="?version=1&table=Table22">10-20%</a> <a href="?version=1&table=Table23">20-30%</a> <a href="?version=1&table=Table24">30-40%</a> <a href="?version=1&table=Table25">40-50%</a> <a href="?version=1&table=Table26">50-60%</a> <a href="?version=1&table=Table27">60-80%</a> </br>- - - - - - - - - - - - - - - - - - - - <br><b>nuclear modification factors (p<sub>T</sub>):</b> <br><i>R<sub>pPb</sub>:</i> <a href="?version=1&table=Table28">0-5%</a> <a href="?version=1&table=Table29">5-10%</a> <a href="?version=1&table=Table30">10-20%</a> <a href="?version=1&table=Table31">20-30%</a> <a href="?version=1&table=Table32">30-40%</a> <a href="?version=1&table=Table33">40-60%</a> <a href="?version=1&table=Table34">60-90%</a> <a href="?version=1&table=Table35">0-90%</a> <br><i>R<sub>AA</sub> (Pb+Pb):</i> <a href="?version=1&table=Table36">0-5%</a> <a href="?version=1&table=Table37">5-10%</a> <a href="?version=1&table=Table38">10-20%</a> <a href="?version=1&table=Table39">20-30%</a> <a href="?version=1&table=Table40">30-40%</a> <a href="?version=1&table=Table41">40-50%</a> <a href="?version=1&table=Table42">50-60%</a> <a href="?version=1&table=Table43">60-80%</a> <br><i>R<sub>AA</sub> (Xe+Xe):</i> <a href="?version=1&table=Table44">0-5%</a> <a href="?version=1&table=Table45">5-10%</a> <a href="?version=1&table=Table46">10-20%</a> <a href="?version=1&table=Table47">20-30%</a> <a href="?version=1&table=Table48">30-40%</a> <a href="?version=1&table=Table49">40-50%</a> <a href="?version=1&table=Table50">50-60%</a> <a href="?version=1&table=Table51">60-80%</a> </br>- - - - - - - - - - - - - - - - - - - - <br><b>nuclear modification factors (y*/eta):</b> <br><i>R<sub>pPb</sub>:</i> <br> 0-5%: <a href="?version=1&table=Table52">0.66-0.755GeV</a> <a href="?version=1&table=Table53">2.95-3.35GeV</a> <a href="?version=1&table=Table54">7.65-8.8GeV</a> <a href="?version=1&table=Table55">15.1-17.3GeV</a> <br> 5-10%: <a href="?version=1&table=Table56">0.66-0.755GeV</a> <a href="?version=1&table=Table57">2.95-3.35GeV</a> <a href="?version=1&table=Table58">7.65-8.8GeV</a> <a href="?version=1&table=Table59">15.1-17.3GeV</a> <br> 10-20%: <a href="?version=1&table=Table60">0.66-0.755GeV</a> <a href="?version=1&table=Table61">2.95-3.35GeV</a> <a href="?version=1&table=Table62">7.65-8.8GeV</a> <a href="?version=1&table=Table63">15.1-17.3GeV</a> <br> 20-30%: <a href="?version=1&table=Table64">0.66-0.755GeV</a> <a href="?version=1&table=Table65">2.95-3.35GeV</a> <a href="?version=1&table=Table66">7.65-8.8GeV</a> <a href="?version=1&table=Table67">15.1-17.3GeV</a> <br> 30-40%: <a href="?version=1&table=Table68">0.66-0.755GeV</a> <a href="?version=1&table=Table69">2.95-3.35GeV</a> <a href="?version=1&table=Table70">7.65-8.8GeV</a> <a href="?version=1&table=Table71">15.1-17.3GeV</a> <br> 40-60%: <a href="?version=1&table=Table72">0.66-0.755GeV</a> <a href="?version=1&table=Table73">2.95-3.35GeV</a> <a href="?version=1&table=Table74">7.65-8.8GeV</a> <a href="?version=1&table=Table75">15.1-17.3GeV</a> <br> 60-90%: <a href="?version=1&table=Table76">0.66-0.755GeV</a> <a href="?version=1&table=Table77">2.95-3.35GeV</a> <a href="?version=1&table=Table78">7.65-8.8GeV</a> <a href="?version=1&table=Table79">15.1-17.3GeV</a> <br> 0-90%: <a href="?version=1&table=Table80">0.66-0.755GeV</a> <a href="?version=1&table=Table81">2.95-3.35GeV</a> <a href="?version=1&table=Table82">7.65-8.8GeV</a> <a href="?version=1&table=Table83">15.1-17.3GeV</a> <br><i>R<sub>AA</sub> (Pb+Pb):</i> <br> 0-5%: <a href="?version=1&table=Table84">1.7-1.95GeV</a> <a href="?version=1&table=Table85">6.7-7.65GeV</a> <a href="?version=1&table=Table86">20-23GeV</a> <a href="?version=1&table=Table87">60-95GeV</a> <br> 5-10%: <a href="?version=1&table=Table88">1.7-1.95GeV</a> <a href="?version=1&table=Table89">6.7-7.65GeV</a> <a href="?version=1&table=Table90">20-23GeV</a> <a href="?version=1&table=Table91">60-95GeV</a> <br> 10-20%: <a href="?version=1&table=Table92">1.7-1.95GeV</a> <a href="?version=1&table=Table93">6.7-7.65GeV</a> <a href="?version=1&table=Table94">20-23GeV</a> <a href="?version=1&table=Table95">60-95GeV</a> <br> 20-30%: <a href="?version=1&table=Table96">1.7-1.95GeV</a> <a href="?version=1&table=Table97">6.7-7.65GeV</a> <a href="?version=1&table=Table98">20-23GeV</a> <a href="?version=1&table=Table99">60-95GeV</a> <br> 30-40%: <a href="?version=1&table=Table100">1.7-1.95GeV</a> <a href="?version=1&table=Table101">6.7-7.65GeV</a> <a href="?version=1&table=Table102">20-23GeV</a> <a href="?version=1&table=Table103">60-95GeV</a> <br> 40-50%: <a href="?version=1&table=Table104">1.7-1.95GeV</a> <a href="?version=1&table=Table105">6.7-7.65GeV</a> <a href="?version=1&table=Table106">20-23GeV</a> <a href="?version=1&table=Table107">60-95GeV</a> <br> 50-60%: <a href="?version=1&table=Table108">1.7-1.95GeV</a> <a href="?version=1&table=Table109">6.7-7.65GeV</a> <a href="?version=1&table=Table110">20-23GeV</a> <a href="?version=1&table=Table111">60-95GeV</a> <br> 60-80%: <a href="?version=1&table=Table112">1.7-1.95GeV</a> <a href="?version=1&table=Table113">6.7-7.65GeV</a> <a href="?version=1&table=Table114">20-23GeV</a> <a href="?version=1&table=Table115">60-95GeV</a> <br><i>R<sub>AA</sub> (Xe+Xe):</i> <br> 0-5%: <a href="?version=1&table=Table116">1.7-1.95GeV</a> <a href="?version=1&table=Table117">6.7-7.65GeV</a> <a href="?version=1&table=Table118">20-23GeV</a> <br> 5-10%: <a href="?version=1&table=Table119">1.7-1.95GeV</a> <a href="?version=1&table=Table120">6.7-7.65GeV</a> <a href="?version=1&table=Table121">20-23GeV</a> <br> 10-20%: <a href="?version=1&table=Table122">1.7-1.95GeV</a> <a href="?version=1&table=Table123">6.7-7.65GeV</a> <a href="?version=1&table=Table124">20-23GeV</a> <br> 20-30%: <a href="?version=1&table=Table125">1.7-1.95GeV</a> <a href="?version=1&table=Table126">6.7-7.65GeV</a> <a href="?version=1&table=Table127">20-23GeV</a> <br> 30-40%: <a href="?version=1&table=Table128">1.7-1.95GeV</a> <a href="?version=1&table=Table129">6.7-7.65GeV</a> <a href="?version=1&table=Table130">20-23GeV</a> <br> 40-50%: <a href="?version=1&table=Table131">1.7-1.95GeV</a> <a href="?version=1&table=Table132">6.7-7.65GeV</a> <a href="?version=1&table=Table133">20-23GeV</a> <br> 50-60%: <a href="?version=1&table=Table134">1.7-1.95GeV</a> <a href="?version=1&table=Table135">6.7-7.65GeV</a> <a href="?version=1&table=Table136">20-23GeV</a> <br> 60-80%: <a href="?version=1&table=Table137">1.7-1.95GeV</a> <a href="?version=1&table=Table138">6.7-7.65GeV</a> <a href="?version=1&table=Table139">20-23GeV</a> <br>- - - - - - - - - - - - - - - - - - - -
Charged-hadron cross-section in pp collisions. The systematic uncertainties are described in the section 7 of the paper. The total systematic uncertainties are determined by adding the contributions from all relevant sources in quadrature.
Charged-hadron spectrum in the centrality interval 0-5% for p+Pb, divided by 〈TPPB〉. The systematic uncertainties are described in the section 7 of the paper. The total systematic uncertainties are determined by adding the contributions from all relevant sources in quadrature.
Multijet events at large transverse momentum ($p_\mathrm{T}$) are measured at $\sqrt{s}$ = 13 TeV using data recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of 36.3 fb$^{-1}$. The multiplicity of jets with $p_\mathrm{T}$$>$ 50 GeV that are produced in association with a high-$p_\mathrm{T}$ dijet system is measured in various ranges of the $p_\mathrm{T}$ of the jet with the highest transverse momentum and as a function of the azimuthal angle difference $\Delta\phi_{1,2}$ between the two highest $p_\mathrm{T}$ jets in the dijet system. The differential production cross sections are measured as a function of the transverse momenta of the four highest $p_\mathrm{T}$ jets. The measurements are compared with leading and next-to-leading order matrix element calculations supplemented with simulations of parton shower, hadronization, and multiparton interactions. In addition, the measurements are compared with next-to-leading order matrix element calculations combined with transverse-momentum dependent parton densities and transverse-momentum dependent parton shower.
Jet multiplicity measured for a leading-pT jet ($p_{T1}$) with 200 < $p_{T1}$ < 400 GeV and for an azimuthal separation between the two leading jets of $0 < \Delta\Phi_{1,2} < 150^{\circ}$. The full breakdown of the uncertainties is displayed, with PU corresponding to Pileup, PREF to Trigger Prefering, PTHAT to the hard-scale (renormalization and factorization scales), MISS and FAKE to the inefficienties and background, LUMI to integrated luminosity. With JES, JER and stat. unc. following the notation in the paper.
Jet multiplicity measured for a leading-pT jet ($p_{T1}$) with 200 < $p_{T1}$ < 400 GeV and for an azimuthal separation between the two leading jets of $150 < \Delta\Phi_{1,2} < 170^{\circ}$. The full breakdown of the uncertainties is displayed, with PU corresponding to Pileup, PREF to Trigger Prefering, PTHAT to the hard-scale (renormalization and factorization scales), MISS and FAKE to the inefficienties and background, LUMI to integrated luminosity. With JES, JER and stat. unc. following the notation in the paper.
Jet multiplicity measured for a leading-pT jet ($p_{T1}$) with 200 < $p_{T1}$ < 400 GeV and for an azimuthal separation between the two leading jets of $170 < \Delta\Phi_{1,2} < 180^{\circ}$. The full breakdown of the uncertainties is displayed, with PU corresponding to Pileup, PREF to Trigger Prefering, PTHAT to the hard-scale (renormalization and factorization scales), MISS and FAKE to the inefficienties and background, LUMI to integrated luminosity. With JES, JER and stat. unc. following the notation in the paper.
A data sample containing top quark pairs ($\mathrm{t\bar{t}}$) produced in association with a Lorentz-boosted Z or Higgs boson is used to search for signs of new physics using effective field theory. The data correspond to an integrated luminosity of 138 fb$^{-1}$ of proton-proton collisions produced at a center-of-mass energy of 13 TeV at the LHC and collected by the CMS experiment. Selected events contain a single lepton and hadronic jets, including two identified with the decay of bottom quarks, plus an additional large-radius jet with high transverse momentum identified as a Z or Higgs boson decaying to a bottom quark pair. Machine learning techniques are employed to discriminate between $\mathrm{t\bar{t}}$Z or $\mathrm{t\bar{t}}$H events and events from background processes, which are dominated by $\mathrm{t\bar{t}}$ + jets production. No indications of new physics are observed. The signal strengths of boosted $\mathrm{t\bar{t}}$Z and $\mathrm{t\bar{t}}$H production are measured, and upper limits are placed on the $\mathrm{t\bar{t}}$Z and $\mathrm{t\bar{t}}$H differential cross sections as functions of the Z or Higgs boson transverse momentum. The effects of new physics are probed using a framework in which the standard model is considered to be the low-energy effective field theory of a higher energy scale theory. Eight possible dimension-six operators are added to the standard model Lagrangian and their corresponding coefficients are constrained via fits to the data.
Negative log-likelihood difference in $\mu_{\text{ttH}}, \mu_{\text{ttZ}}$ for a Z or Higgs boson with a simulated pT $> 200$GeV
Negative log-likelihood difference in $\text{c}_{\text{t}\varphi}$ where the other Wilson coefficients are fixed to 0.
Negative log-likelihood difference in $\text{c}_{\varphi\text{Q}}^{-}$ where the other Wilson coefficients are fixed to 0.
We report about the properties of the underlying event measured with ALICE at the LHC in pp and p$-$Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV. The event activity, quantified by charged-particle number and summed-$p_{\rm T}$ densities, is measured as a function of the leading-particle transverse momentum ($p_{\rm T}^{\rm trig}$). These quantities are studied in three azimuthal-angle regions relative to the leading particle in the event: toward, away, and transverse. Results are presented for three different $p_{\rm T}$ thresholds (0.15, 0.5, and 1 GeV/$c$) at mid-pseudorapidity ($|\eta|<0.8$). The event activity in the transverse region, which is the most sensitive to the underlying event, exhibits similar behaviour in both pp and p$-$Pb collisions, namely, a steep increase with $p_{\rm T}^{\rm trig}$ for low $p_{\rm T}^{\rm trig}$, followed by a saturation at $p_{\rm T}^{\rm trig} \approx 5$ GeV/$c$. The results from pp collisions are compared with existing measurements at other centre-of-mass energies. The quantities in the toward and away regions are also analyzed after the subtraction of the contribution measured in the transverse region. The remaining jet-like particle densities are consistent in pp and p$-$Pb collisions for $p_{\rm T}^{\rm trig}>10$ GeV/$c$, whereas for lower $p_{\rm T}^{\rm trig}$ values the event activity is slightly higher in p$-$Pb than in pp collisions. The measurements are compared with predictions from the PYTHIA 8 and EPOS LHC Monte Carlo event generators.
Fig. 4: Number density $N_{\rm ch}$ (left) and $\Sigma p_{\rm T}$ (right) distributions as a function of $p_{\rm T}^{\rm trig}$ in Transverse, Away, and Toward regions for $p_{\rm T} >$ 0.5 GeV/$c$. The shaded areas and the error bars around the data points represent the systematic and statistical uncertainties, respectively.
Fig. 5: Number density $N_{\rm ch}$ (left) and $\Sigma p_{\rm T}$ (right) distributions as a function of $p_{\rm T}^{\rm trig}$ in Transverse, Away, and Toward regions for $p_{\rm T} >$ 0.5 GeV/$c$. The shaded areas and the error bars around the data points represent the systematic and statistical uncertainties, respectively.
Fig. 6a: Number density $N_{\rm ch}$ (left) and $\Sigma p_{\rm T}$ (right) distributions as a function of $p_{\rm T}^{\rm trig}$ in Away and Toward regions after the subtraction of Number density $N_{\rm ch}$ and $\Sigma p_{\rm T}$ distributions in the transverse region for pp collisions for $p_{\rm T} >$ 0.5 GeV/$c$. The shaded areas and the error bars around the data points represent the systematic and statistical uncertainties, respectively.
Suppression of the $J/\psi$ nuclear-modification factor has been seen as a trademark signature of final-state effects in large collision systems for decades. In small systems, the nuclear modification was attributed to cold-nuclear-matter effects until the observation of strong differential suppression of the $\psi(2S)$ state in $p/d$ $+$ $A$ collisions suggested the presence of final-state effects. Results of $J/\psi$ and $\psi(2S)$ measurements in the dimuon decay channel are presented here for $p$ $+$ $p$, $p$ $+$Al, and $p$ $+$Au collision systems at $\sqrt{s_{_{NN}}}=200$ GeV. The results are predominantly shown in the form of the nuclear-modification factor, $R_{pA}$, the ratio of the $\psi(2S)$ invariant yield per nucleon-nucleon collision in collisions of proton on target nucleus to that in $p$ $+$ $p$ collisions. Measurements of the $J/\psi$ and $\psi(2S)$ nuclear-modification factor are compared with shadowing and transport-model predictions, as well as to complementary measurements at Large-Hadron-Collider energies.
PSI(2S)-->MU+MU- invariant yields in p+p, p+Al, and p+Au collisions as a function of rapidity. The statistical and systematic uncertainties vary point-to-point and are listed for each measured value. An additional global systematic uncertainty is provided in each column heading, which applies to all data points per column.
J/PSI(1S)-->MU+MU- invariant yields in p+p, p+Al, and p+Au collisions as a function of rapidity. The statistical and systematic uncertainties vary point-to-point and are listed for each measured value. An additional global systematic uncertainty is provided in each column heading, which applies to all data points per column.
PSI(2S)-->MU+MU- nuclear modification in p+Al collisions as a function of rapidity. The statistical and systematic uncertainties vary point-to-point and are listed for each measured value. An additional global systematic uncertainty is provided in each column heading, which applies to all data points per column.
This paper presents studies of Bose-Einstein correlations (BEC) in proton-proton collisions at a centre-of-mass energy of 13 TeV, using data from the ATLAS detector at the CERN Large Hadron Collider. Data were collected in a special low-luminosity configuration with a minimum-bias trigger and a high-multiplicity track trigger, accumulating integrated luminosities of 151 $\mu$b$^{-1}$ and 8.4 nb$^{-1}$ respectively. The BEC are measured for pairs of like-sign charged particles, each with $|\eta|$ < 2.5, for two kinematic ranges: the first with particle $p_T$ > 100 MeV and the second with particle $p_T$ > 500 MeV. The BEC parameters, characterizing the source radius and particle correlation strength, are investigated as functions of charged-particle multiplicity (up to 300) and average transverse momentum of the pair (up to 1.5 GeV). The double-differential dependence on charged-particle multiplicity and average transverse momentum of the pair is also studied. The BEC radius is found to be independent of the charged-particle multiplicity for high charged-particle multiplicity (above 100), confirming a previous observation at lower energy. This saturation occurs independent of the transverse momentum of the pair.
Comparison of single-ratio two-particle correlation functions, C<sub>2</sub><sup>data</sup>(Q) and C<sub>2</sub><sup>MC</sup>(Q), with the two-particle double-ratio correlation function, R<sub>2</sub>(Q), for the high-multiplicity track (HMT) events using the opposite hemisphere (OHP) like-charge particles pairs reference sample for k<sub>T</sub> - interval 1000 < k<sub>T</sub> ≤ 1500 MeV.
Comparison of single-ratio two-particle correlation functions, C<sub>2</sub><sup>data</sup>(Q) and C<sub>2</sub><sup>MC</sup>(Q), with the two-particle double-ratio correlation function, R<sub>2</sub>(Q), for the high-multiplicity track (HMT) events using the unlike-charge particle (UCP) pairs reference sample for k<sub>T</sub> - interval 1000 < k<sub>T</sub> ≤ 1500 MeV.
The Bose-Einstein correlation (BEC) parameter R as a function of n<sub>ch</sub> for MB events using different MC generators in the calculation of R<sub>2</sub>(Q). The uncertainties shown are statistical. The lower panel of each plot shows the ratio of the BEC parameters obtained using EPOS LHC (red circles), Pythia 8 Monash (blue squares) and Herwig++ UE-EE-5 (green triangles) compared with the parameters obtained using Pythia 8 A2. The gray band in the lower panels is the MC systematic uncertainty, obtained as explained in the text.
The production cross section of a top quark pair in association with a photon is measured in proton-proton collisions in the decay channel with two oppositely charged leptons (e$^\pm\mu^\mp$, e$^+$e$^-$, or $\mu^+\mu^-$). The measurement is performed using 138 fb$^{-1}$ of proton-proton collision data recorded by the CMS experiment at $\sqrt{s} =$ 13 TeV during the 2016-2018 data-taking period of the CERN LHC. A fiducial phase space is defined such that photons radiated by initial-state particles, top quarks, or any of their decay products are included. An inclusive cross section of 175.2 $\pm$ 2.5 (stat) $\pm$ 6.3 (syst) fb is measured in a signal region with at least one jet coming from the hadronization of a bottom quark and exactly one photon with transverse momentum above 20 GeV. Differential cross sections are measured as functions of several kinematic observables of the photon, leptons, and jets, and compared to standard model predictions. The measurements are also interpreted in the standard model effective field theory framework, and limits are found on the relevant Wilson coefficients from these results alone and in combination with a previous CMS measurement of the $\mathrm{t\bar{t}}\gamma$ production process using the lepton+jets final state.
Observed and predicted event yields as a function of $p_{T}(\gamma)$ in the $e\mu$ channel, after the fit to the data.
Observed and predicted event yields as a function of $p_{T}(\gamma)$ in the $ee$ channel, after the fit to the data.
Observed and predicted event yields as a function of $p_{T}(\gamma)$ in the $\mu\mu$ channel, after the fit to the data.
A measurement of the cross section of the associated production of a single top quark and a W boson in final states with a muon or electron and jets in proton-proton collisions at $\sqrt{s}$ = 13 TeV is presented. The data correspond to an integrated luminosity of 36 fb$^{-1}$ collected with the CMS detector at the CERN LHC in 2016. A boosted decision tree is used to separate the tW signal from the dominant $\mathrm{t\bar{t}}$ background, whilst the subleading W+jets and multijet backgrounds are constrained using data-based estimates. This result is the first observation of the tW process in final states containing a muon or electron and jets, with a significance exceeding 5 standard deviations. The cross section is determined to be 89 $\pm$ 4 (stat) $\pm$ 12 (syst) pb, consistent with the standard model.
The observed and theoretical cross section. In the observed, the first uncertainty is statistical, the second uncertianty is the systematic. In the expected, the first uncertainty is due to scale variations, the second due to the choice of PDF.
The systematic sources considered in the analysis and their relative contribution to the observed uncertainty. The uncertainties are divided by normalization, experimental, theoretical and statistical uncertainties, with each section ordered by their contribution to the total uncertainty.
Conventional hadronic matter consists of baryons and mesons made of three quarks and quark-antiquark pairs, respectively. The observation of a new type of hadronic state, a doubly charmed tetraquark containing two charm quarks, an anti-$u$ and an anti-$d$ quark, is reported using data collected by the LHCb experiment at the Large Hadron Collider. This exotic state with a mass of about 3875 MeV$/c^2$ manifests itself as a narrow peak in the mass spectrum of $D^0D^0\pi^+$ mesons just below the $D^{*+}D^0$ mass threshold. The near threshold mass together with a strikingly narrow width reveals the resonance nature of the state.
Distribution of $D^0 D^0 \pi^+$ mass where the contribution of the non-$D^0$ background has been statistically subtracted. Uncertainties on the data points are statistical only and represent one standard deviation, calculated as a sum in quadrature of the assigned weights from the background-subtraction procedure.
Distribution of $D^0 D^0 \pi^+$ mass where the contribution of the non-$D^0$ background has been statistically subtracted by assigning the a weight to every candidate.
An exotic narrow state in the $D^0D^0\pi^+$ mass spectrum just below the $D^{*+}D^0$ mass threshold is studied using a data set corresponding to an integrated luminosity of 9 fb$^{-1}$ acquired with the LHCb detector in proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV. The state is consistent with the ground isoscalar $T^+_{cc}$ tetraquark with a quark content of $cc\bar{u}\bar{d}$ and spin-parity quantum numbers $\mathrm{J}^{\mathrm{P}}=1^+$. Study of the $DD$ mass spectra disfavours interpretation of the resonance as the isovector state. The decay structure via intermediate off-shell $D^{*+}$ mesons is confirmed by the $D^0\pi^+$ mass distribution. The mass of the resonance and its coupling to the $D^{*}D$ system are analysed. Resonance parameters including the pole position, scattering length, effective range and compositeness are measured to reveal important information about the nature of the $T^+_{cc}$ state. In addition, an unexpected dependence of the production rate on track multiplicity is observed.
Distribution of $D^0 D^0 \pi^+$ mass where the contribution of the non-$D^0$ background has been statistically subtracted. Uncertainties on the data points are statistical only and represent one standard deviation, calculated as a sum in quadrature of the assigned weights from the background-subtraction procedure.
Mass distribution for $D^0 \pi^+$ pairs from selected $D^0 D^0 \pi^+$ candidates with a mass below the $D^{*+}D^0$ mass threshold with non-$D^0$ background subtracted. Uncertainties on the data points are statistical only and represent one standard deviation, calculated as a sum in quadrature of the assigned weights from the background-subtraction procedure.
$D^0 D^0$~mass distributions for selected candidates with the $D^0$ background subtracted. Uncertainties on the data points are statistical only and represent one standard deviation, calculated as a sum in quadrature of the assigned weights from the background-subtraction procedure.
The production of prompt charged particles in proton-lead collisions and in proton-proton collisions at the nucleon-nucleon centre-of-mass energy ${\sqrt{s_{\scriptscriptstyle\mathrm{NN}}}=5\,\mathrm{TeV}}$ is studied at LHCb as a function of pseudorapidity ($\eta$) and transverse momentum ($p_{\mathrm{T}}$) with respect to the proton beam direction. The nuclear modification factor for charged particles is determined as a function of $\eta$ between ${-4.8<\eta<-2.5}$ (backward region) and ${2.0<\eta<4.8}$ (forward region), and $p_{\mathrm{T}}$ between ${0.2<p_{\mathrm{T}}<8.0\,\mathrm{GeV}/c}$. The results show a suppression of charged particle production in proton-lead collisions relative to proton-proton collisions in the forward region and an enhancement in the backward region for $p_{\mathrm{T}}$ larger than $1.5\,\mathrm{GeV}/c$. This measurement constrains nuclear PDFs and saturation models at previously unexplored values of the parton momentum fraction down to $10^{-6}$.
Double-differential production cross-section for prompt charged particles in pp collisions at 5TeV with respect to pseudorapidity and transverse momentum. First uncertainty is statistical, the second is systematic and the third is from the luminosity. Luminosity uncertainty is fully correlated among the different kinematic ranges.
Double-differential production cross-section for prompt charged particles in pPb collisions at 5TeV with respect to pseudorapidity and transverse momentum in the forward region. The pseudorapidity is expressed in the nucleon-nucleon center-of-mass system. First uncertainty is statistical, the second is systematic and the third is from the luminosity. Luminosity uncertainty is fully correlated among the different kinematic ranges.
Double-differential production cross-section for prompt charged particles in pPb collisions at 5TeV with respect to pseudorapidity and transverse momentum in the backward region. The pseudorapidity is expressed in the nucleon-nucleon center-of-mass system. First uncertainty is statistical, the second is systematic and the third is from the luminosity. Luminosity uncertainty is fully correlated among the different kinematic ranges.
We report the first multi-differential measurements of strange hadrons of $K^{-}$, $\phi$ and $\Xi^{-}$ yields as well as the ratios of $\phi/K^-$ and $\phi/\Xi^-$ in Au+Au collisions at ${\sqrt{s_{\rm NN}} = \rm{3\,GeV}}$ with the STAR experiment fixed target configuration at RHIC. The $\phi$ mesons and $\Xi^{-}$ hyperons are measured through hadronic decay channels, $\phi\rightarrow K^+K^-$ and $\Xi^-\rightarrow \Lambda\pi^-$. Collision centrality and rapidity dependence of the transverse momentum spectra for these strange hadrons are presented. The $4\pi$ yields and ratios are compared to thermal model and hadronic transport model predictions. At this collision energy, thermal model with grand canonical ensemble (GCE) under-predicts the $\phi/K^-$ and $\phi/\Xi^-$ ratios while the result of canonical ensemble (CE) calculations reproduce $\phi/K^-$, with the correlation length $r_c \sim 2.7$ fm, and $\phi/\Xi^-$, $r_c \sim 4.2$ fm, for the 0-10% central collisions. Hadronic transport models including high mass resonance decays could also describe the ratios. While thermal calculations with GCE work well for strangeness production in high energy collisions, the change to CE at $\rm{3\,GeV}$ implies a rather different medium property at high baryon density.
$K^-$ (a), invariant yields as a function of $m_T-m_0$ for various rapidity regions in 0--10\% central Au+Au collisions at ${\sqrt{s_{\mathrm{NN}}} = \mathrm{3\,GeV}}$. Statistics and systematic uncertainties are added quadratic here for plotting. Solid and dashed black lines depict $m_T$ exponential function fits to the measured data points with arbitrate scaling factors in each rapidity windows.
$\phi$ meson (b) invariant yields as a function of $m_T-m_0$ for various rapidity regions in 0--10\% central Au+Au collisions at ${\sqrt{s_{\mathrm{NN}}} = \mathrm{3\,GeV}}$. Statistics and systematic uncertainties are added quadratic here for plotting. Solid and dashed black lines depict $m_T$ exponential function fits to the measured data points with arbitrate scaling factors in each rapidity windows.
$\Xi^-$ (c) invariant yields as a function of $m_T-m_0$ for various rapidity regions in 0--10\% central Au+Au collisions at ${\sqrt{s_{\mathrm{NN}}} = \mathrm{3\,GeV}}$. Statistics and systematic uncertainties are added quadratic here for plotting. Solid and dashed black lines depict $m_T$ exponential function fits to the measured data points with arbitrate scaling factors in each rapidity windows.
The production cross section of a top quark pair in association with a photon is measured in proton-proton collisions at a center-of-mass energy of 13 TeV. The data set, corresponding to an integrated luminosity of 137 fb$^{-1}$, was recorded by the CMS experiment during the 2016-2018 data taking of the LHC. The measurements are performed in a fiducial volume defined at the particle level. Events with an isolated, highly energetic lepton, at least three jets from the hadronization of quarks, among which at least one is b tagged, and one isolated photon are selected. The inclusive fiducial $\mathrm{t\overline{t}}\gamma$ cross section, for a photon with transverse momentum greater than 20 GeV and pseudorapidity $\lvert \eta\rvert$$\lt$ 1.4442, is measured to be 798 $\pm$ 7 (stat) $\pm$ 48 (syst) fb, in good agreement with the prediction from the standard model at next-to-leading order in quantum chromodynamics. The differential cross sections are also measured as a function of several kinematic observables and interpreted in the framework of the standard model effective field theory (EFT), leading to the most stringent direct limits to date on anomalous electromagnetic dipole moment interactions of the top quark and the photon.
Distribution of $p_{T}(\gamma)$ in the $N_{jet}\geq 3$ signal region.
Distribution of $p_{T}(\gamma)$ in the $N_{jet}\geq 3$ signal region.
Distribution of $m_{T}(W)$ in the $N_{jet}\geq 3$ signal region.
Double-parton scattering is investigated using events with a Z boson and jets. The Z boson is reconstructed using only the dimuon channel. The measurements are performed with proton-proton collision data recorded by the CMS experiment at the LHC at $\sqrt{s} =$ 13 TeV, corresponding to an integrated luminosity of 35.9 fb$^{-1}$ collected in the year 2016. Differential cross sections of Z + $\geq$ 1 jet and Z + $\geq$ 2 jets are measured with transverse momentum of the jets above 20 GeV and pseudorapidity $|\eta|$$\lt$ 2.4. Several distributions with sensitivity to double-parton scattering effects are measured as functions of the angle and the transverse momentum imbalance between the Z boson and the jets. The measured distributions are compared with predictions from several event generators with different hadronization models and different parameter settings for multiparton interactions. The measured distributions show a dependence on the hadronization and multiparton interaction simulation parameters, and are important input for future improvements of the simulations.
Differential cross sections as function of Delta Phi between Z boson and the leading jet for Z+ ≥ 1 jet events.
Differential cross sections as function of transverse momentum imbalance between Z boson and the leading jet for Z+ ≥ 1 jet events.
Differential cross sections as function of Delta Phi between Z boson and dijet for Z+ ≥ 2 jets events.
The results of a search for gluino and squark pair production with the pairs decaying via the lightest charginos into a final state consisting of two $W$ bosons, the lightest neutralinos ($\tilde\chi^0_1$), and quarks, are presented. The signal is characterised by the presence of a single charged lepton ($e^{\pm}$ or $\mu^{\pm}$) from a $W$ boson decay, jets, and missing transverse momentum. The analysis is performed using 139 fb$^{-1}$ of proton-proton collision data taken at a centre-of-mass energy $\sqrt{s}=13$ TeV delivered by the Large Hadron Collider and recorded by the ATLAS experiment. No statistically significant excess of events above the Standard Model expectation is found. Limits are set on the direct production of squarks and gluinos in simplified models. Masses of gluino (squark) up to 2.2 TeV (1.4 TeV) are excluded at 95% confidence level for a light $\tilde\chi^0_1$.
Post-fit $m_{T}$ distribution in the SR 2J b-veto N-1 region. N-1 refers to all cuts except for the requirement on $m_T$ being applied. Uncertainties include statistical and systematic uncertainties. The value 9999 is used as a placeholder for infinity.
Post-fit $m_{T}$ distribution in the SR 2J b-veto N-1 region. N-1 refers to all cuts except for the requirement on $m_T$ being applied. Uncertainties include statistical and systematic uncertainties. The value 9999 is used as a placeholder for infinity.
Post-fit $m_{T}$ distribution in the SR 2J b-tag N-1 region. N-1 refers to all cuts except for the requirement on $m_T$ being applied. Uncertainties include statistical and systematic uncertainties. The value 9999 is used as a placeholder for infinity.
The inclusive $b \bar{b}$- and $c \bar{c}$-dijet production cross-sections in the forward region of $pp$ collisions are measured using a data sample collected with the LHCb detector at a centre-of-mass energy of 13 TeV in 2016. The data sample corresponds to an integrated luminosity of 1.6 fb$^{-1}$. Differential cross-sections are measured as a function of the transverse momentum and of the pseudorapidity of the leading jet, of the rapidity difference between the jets, and of the dijet invariant mass. A fiducial region for the measurement is defined by requiring that the two jets originating from the two $b$ or $c$ quarks are emitted with transverse momentum greater than 20 GeV$/c$, pseudorapidity in the range $2.2 < \eta < 4.2$, and with a difference in the azimuthal angle between the two jets greater than 1.5. The integrated $b \bar{b}$-dijet cross-section is measured to be $53.0 \pm 9.7$ nb, and the total $c \bar{c}$-dijet cross-section is measured to be $73 \pm 16$ nb. The ratio between $c \bar{c}$- and $b \bar{b}$-dijet cross-sections is also measured and found to be $1.37 \pm 0.27$. The results are in agreement with theoretical predictions at next-to-leading order.
The total $b \bar{b}$-dijet and $c \bar{c}$-dijet cross-sections and their ratio in the fiducial region, compared with the NLO predictions. The first uncertainty is the combined statistical and systematic uncertainty and the second is the uncertainty from the luminosity. For the predictions, the first uncertainty corresponds to the scale uncertainty, the second to the PDF uncertainty.
Numerical results of $b \bar{b}$- and $c \bar{c}$-dijet cross-sections, $c \bar{c}$/$b \bar{b}$ dijet cross-section ratios and their total uncertainties as a function of the leading jet $\eta$ (pseudorapidity).
Numerical results of $b \bar{b}$- and $c \bar{c}$-dijet cross-sections, $c \bar{c}$/$b \bar{b}$ dijet cross-section ratios and their total uncertainties as a function of $\Delta y^*$.
The observation of forward proton scattering in association with lepton pairs ($e^+e^-+p$ or $\mu^+\mu^-+p$) produced via photon fusion is presented. The scattered proton is detected by the ATLAS Forward Proton spectrometer while the leptons are reconstructed by the central ATLAS detector. Proton-proton collision data recorded in 2017 at a center-of-mass energy of $\sqrt{s} = 13$ TeV are analyzed, corresponding to an integrated luminosity of 14.6 fb$^{-1}$. A total of 57 (123) candidates in the $ee+p$ ($\mu\mu+p$) final state are selected, allowing the background-only hypothesis to be rejected with a significance exceeding five standard deviations in each channel. Proton-tagging techniques are introduced for cross-section measurements in the fiducial detector acceptance, corresponding to $\sigma_{ee+p}$ = 11.0 $\pm$ 2.6 (stat.) $\pm$ 1.2 (syst.) $\pm$ 0.3 (lumi.) fb and $\sigma_{\mu\mu+p}$ = 7.2 $\pm$ 1.6 (stat.) $\pm$ 0.9 (syst.) $\pm$ 0.2 (lumi.) fb in the dielectron and dimuon channel, respectively.
The measured fiducial cross sections. The first systematic uncertainty is the combined systematic uncertainty excluding luminosity, the second is the luminosity
Inclusive and differential cross-sections for the production of top quarks in association with a photon are measured with proton$-$proton collision data corresponding to an integrated luminosity of 139 fb$^{-1}$. The data were collected by the ATLAS detector at the LHC during Run 2 between 2015 and 2018 at a centre-of-mass energy of 13 TeV. The measurements are performed in a fiducial volume defined at parton level. Events with exactly one photon, one electron and one muon of opposite sign, and at least two jets, of which at least one is $b$-tagged, are selected. The fiducial cross-section is measured to be $39.6\,^{+2.7}_{-2.3}\,\textrm{fb}$. Differential cross-sections as functions of several observables are compared with state-of-the-art Monte Carlo simulations and next-to-leading-order theoretical calculations. These include cross-sections as functions of photon kinematic variables, angular variables related to the photon and the leptons, and angular separations between the two leptons in the event. All measurements are in agreement with the predictions from the Standard Model.
The measured fiducial cross-section in the electron-muon channel. The first uncertainty is the statistical uncertainty and the second one is the systematic uncertainty.
The absolute differential cross-section measured in the fiducial phase-space as a function of the photon pT in the electron-muon channel. The uncertainty is decomposed into four components which are the signal modelling uncertainty, the background modelling uncertainty, the experimental uncertainty, and the data statistical uncertainty.
The absolute differential cross-section measured in the fiducial phase-space as a function of the photon $|\eta|$ in the electron-muon channel. The uncertainty is decomposed into four components which are the signal modelling uncertainty, the background modelling uncertainty, the experimental uncertainty, and the data statistical uncertainty.
The $t\bar{t}$ production cross-section is measured in the lepton+jets channel using proton$-$proton collision data at a centre-of-mass energy of $\sqrt{s}=13$ TeV collected with the ATLAS detector at the LHC. The dataset corresponds to an integrated luminosity of 139 fb$^{-1}$. Events with exactly one charged lepton and four or more jets in the final state, with at least one jet containing $b$-hadrons, are used to determine the $t\bar{t}$ production cross-section through a profile-likelihood fit. The inclusive cross-section is measured to be ${\sigma_{\text{inc}} = 830 \pm 0.4~ \text{(stat.)}\pm 36~\text{(syst.)}\pm 14~\text{(lumi.)}~\mathrm{pb}}$ with a relative uncertainty of 4.6 %. The result is consistent with theoretical calculations at next-to-next-to-leading order in perturbative QCD. The fiducial $t\bar{t}$ cross-section within the experimental acceptance is also measured.
The results of fitted inclusive and fiducial ${t\bar{t}}$ cross-sections
The results of fitted inclusive and fiducial ${t\bar{t}}$ cross-sections
Ranking of the systematic uncertainties on the measured cross-section, normalised to the predicted value, in the inclusive fit to data. The impact of each nuisance parameter, $\Delta \sigma_{\text{inc}}/\sigma^{\text{pred.}}_{\text{inc}}$, is computed by comparing the nominal best-fit value of $\sigma_{\text{inc}}/\sigma^{\text{pred}}_{\text{inc}}$ with the result of the fit when fixing the considered nuisance parameter to its best-fit value, $\theta$, shifted by its pre-fit (post-fit) uncertainties $\pm \Delta \theta$ ($\pm \Delta \hat{\theta}$). The figure shows the effect of the ten most significant uncertainties.
A search for heavy neutral Higgs bosons is performed using the LHC Run 2 data, corresponding to an integrated luminosity of 139 fb$^{-1}$ of proton-proton collisions at $\sqrt{s}=13$ TeV recorded with the ATLAS detector. The search for heavy resonances is performed over the mass range 0.2-2.5 TeV for the $\tau^+\tau^-$ decay with at least one $\tau$-lepton decaying into final states with hadrons. The data are in good agreement with the background prediction of the Standard Model. In the $M_{h}^{125}$ scenario of the Minimal Supersymmetric Standard Model, values of $\tan\beta>8$ and $\tan\beta>21$ are excluded at the 95% confidence level for neutral Higgs boson masses of 1.0 TeV and 1.5 TeV, respectively, where $\tan\beta$ is the ratio of the vacuum expectation values of the two Higgs doublets.
Observed and predicted mTtot distribution in the b-veto category of the 1l1tau_h channel. Please note that the bin content is divided by the bin width in the paper figure, but not in the HepData table.The last bin includes overflows. The combined prediction for A and H bosons with masses of 400, 1000 and 1500 GeV and $\tan\beta$ = 6, 12 and 25 respectively in the mh125 scenario are also provided. The combined prediction for A and H bosons with masses of 1000 and 1500 GeV is scaled by 100 in the paper figure, but not in the HepData table.
Observed and predicted mTtot distribution in the b-veto category of the 1l1tau_h channel. Please note that the bin content is divided by the bin width in the paper figure, but not in the HepData table.The last bin includes overflows. The combined prediction for A and H bosons with masses of 400, 1000 and 1500 GeV and $\tan\beta$ = 6, 12 and 25 respectively in the mh125 scenario are also provided. The combined prediction for A and H bosons with masses of 1000 and 1500 GeV is scaled by 100 in the paper figure, but not in the HepData table.
Observed and predicted mTtot distribution in the b-veto category of the 1l1tau_h channel. Please note that the bin content is divided by the bin width in the paper figure, but not in the HepData table.The last bin includes overflows. The combined prediction for A and H bosons with masses of 400, 1000 and 1500 GeV and $\tan\beta$ = 6, 12 and 25 respectively in the mh125 scenario are also provided. The combined prediction for A and H bosons with masses of 1000 and 1500 GeV is scaled by 100 in the paper figure, but not in the HepData table.
This paper describes precision measurements of the transverse momentum $p_\mathrm{T}^{\ell\ell}$ ($\ell=e,\mu$) and of the angular variable $\phi^{*}_{\eta}$ distributions of Drell-Yan lepton pairs in a mass range of 66-116 GeV. The analysis uses data from 36.1 fb$^{-1}$ of proton-proton collisions at a centre-of-mass energy of $\sqrt{s}=13$ TeV collected by the ATLAS experiment at the LHC in 2015 and 2016. Measurements in electron-pair and muon-pair final states are performed in the same fiducial volumes, corrected for detector effects, and combined. Compared to previous measurements in proton-proton collisions at $\sqrt{s}=$7 and 8 TeV, these new measurements probe perturbative QCD at a higher centre-of-mass energy with a different composition of initial states. They reach a precision of 0.2% for the normalized spectra at low values of $p_\mathrm{T}^{\ell\ell}$. The data are compared with different QCD predictions, where it is found that predictions based on resummation approaches can describe the full spectrum within uncertainties.
Selected signal candidate events in data for both decay channels as well as the expected background contributions including their total uncertainties.
Selected signal candidate events in data for both decay channels as well as the expected background contributions including their total uncertainties.
Selected signal candidate events in data for both decay channels as well as the expected background contributions including their total uncertainties.
The production of a prompt photon in association with a $Z$ boson is studied in proton-proton collisions at a centre-of-mass energy $\sqrt{s} =$ 13 TeV. The analysis uses a data sample with an integrated luminosity of 139 fb$^{-1}$ collected by the ATLAS detector at the LHC from 2015 to 2018. The production cross-section for the process $pp \rightarrow \ell^+\ell^-\gamma+X$ ($\ell = e, \mu$) is measured within a fiducial phase-space region defined by kinematic requirements on the photon and the leptons, and by isolation requirements on the photon. An experimental precision of 2.9% is achieved for the fiducial cross-section. Differential cross-sections are measured as a function of each of six kinematic variables characterising the $\ell^+\ell^-\gamma$ system. The data are compared with theoretical predictions based on next-to-leading-order and next-to-next-to-leading-order perturbative QCD calculations. The impact of next-to-leading-order electroweak corrections is also considered.
The measured fiducial cross section. "Uncor" uncertainty includes all systematic uncertainties that are uncorrelated between electron and muon channels such as the uncertainty on the electron identification efficiency and the uncorrelated component of the background uncertainties. The parton-to-particle correction factor $C_{theory}$ is the ratio of the cross-section predicted by Sherpa LO samples at particle level within the fiducial phase-space region defined in Table 4 to the predicted cross-section at parton level within the same fiducial region but with the smooth-cone isolation prescription defined above replacing the particle-level photon isolation criterion, and with Born-level leptons in place of dressed leptons. This correction should be applied on fixed order parton-level calculations. The systematic uncertainty is evaluated from a comparison with the correction factor obtained using events generated with SHERPA 2.2.2 at NLO. In the case that the calculations are valid for dressed leptons, a modified correction factor excluding the Born-to-dressed lepton correction should be applied instead. This correction only takes into account the particle-level isolation criteria, and is provided separately here. The Sherpa 2.2.8 NLO cross-sections given below include a small contribution from EW $Z\gamma jj$ production of 4.57 fb.
The measured fiducial cross section. "Uncor" uncertainty includes all systematic uncertainties that are uncorrelated between electron and muon channels such as the uncertainty on the electron identification efficiency and the uncorrelated component of the background uncertainties. The parton-to-particle correction factor $C_{theory}$ is the ratio of the cross-section predicted by Sherpa LO samples at particle level within the fiducial phase-space region defined in Table 4 to the predicted cross-section at parton level within the same fiducial region but with the smooth-cone isolation prescription defined above replacing the particle-level photon isolation criterion, and with Born-level leptons in place of dressed leptons. This correction should be applied on fixed order parton-level calculations. The systematic uncertainty is evaluated from a comparison with the correction factor obtained using events generated with Sherpa 2.2.2 at NLO. In the case that the calculations are valid for dressed leptons, a modified correction factor excluding the Born-to-dressed lepton correction should be applied instead. This correction only takes into account the particle-level isolation criteria, and is provided separately here. The Sherpa 2.2.8 NLO cross-sections given below include a small contribution from EW $Z\gamma jj$ production of 4.57 fb.
The measured fiducial cross section vs $E_{\mathrm{T}}^\gamma$. The central values are provided along with the statistical and systematic uncertainties together with the sign information. The statistical and "Uncor" uncertainty should be treated as uncorrelated bin-to-bin, while the rest are correlated between bins, and they are written as signed NP variations. The parton-to-particle correction factor $C_{theory}$ is the ratio of the cross-section predicted by Sherpa LO samples at particle level within the fiducial phase-space region defined in Table 4 to the predicted cross-section at parton level within the same fiducial region but with the smooth-cone isolation prescription defined above replacing the particle-level photon isolation criterion, and with Born-level leptons in place of dressed leptons. This correction should be applied on fixed order parton-level calculations. The systematic uncertainty is evaluated from a comparison with the correction factor obtained using events generated with SHERPA 2.2.2 at NLO. In the case that the calculations are valid for dressed leptons, a modified correction factor excluding the Born-to-dressed lepton correction should be applied instead. This correction only takes into account the particle-level isolation criteria, and is provided separately here. The Sherpa 2.2.8 NLO cross-sections given below include a small contribution from EW $Z\gamma jj$ production.
Using a data sample corresponding to an integrated luminosity of $2.0\,fb^{-1}$, collected by the LHCb experiment, the production of the $\eta_c(1S)$ state in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}=13 \text{ TeV}$ is studied in the rapidity range ${2.0 < y < 4.5}$ and in the transverse momentum range ${6.5 < p_{T} < 14.0\text{ GeV}}$. The cross-section for prompt production of $\eta_c(1S)$ mesons relative to that of the $J/\psi$ meson is measured using the ${p\bar{p}}$ decay mode and is found to be ${\sigma_{\eta_c(1S)}/\sigma_{J/\psi} = 1.69 \pm 0.15 \pm 0.10 \pm 0.18}$. The quoted uncertainties are, in order, statistical, systematic and due to uncertainties on the branching fractions of the ${J/\psi\to p \bar{p}}$ and ${\eta_c\to p \bar{p}}$ decays. The prompt $\eta_c(1S)$ production cross-section is determined to be ${\sigma_{\eta_c(1S)} = 1.26 \pm 0.11\pm 0.08 \pm 0.14 \,\mu b}$, where the last uncertainty includes that on the ${J/\psi}$ meson cross-section. The ratio of the branching fractions of $b$-hadron decays to the $\eta_c(1S)$ and ${J/\psi}$ states is measured to be ${\mathcal{B}_{b\to\eta_c X}/\mathcal{B}_{b\to J/\psi X} = 0.48 \pm 0.03 \pm 0.03 \pm 0.05}$, where the last uncertainty is due to those on the branching fractions of the ${J/\psi \to p \bar{p}}$ and ${\eta_c\to p \bar{p}}$ decays. The difference between the ${J/\psi}$ and $\eta_c(1S)$ masses is also determined to be ${113.0 \pm 0.7 \pm 0.1\text{ MeV}}$, which is the most precise single measurement of this quantity to date.
Relative $\eta_c$ to $J/\psi$ differential production cross-sections for prompt production. The uncertainties are statistical, systematic, and due to the ${\eta_c\to p\bar{p}}$ and ${J/\psi\to p\bar{p}}$ branching fractions, respectively.
Differential production cross-sections of $\eta_c$ for prompt production. The uncertainties are statistical, systematic, and due to the $\eta_c\to p \bar{p}$ and $J/\psi\to p \bar{p}$ branching fractions and $J/\psi$ production cross-section.
Relative $\eta_c$ to $J/\psi$ differential production cross-sections for production in $b$-hadron inclusive decays. The uncertainties are statistical, systematic, and due to the ${\eta_c\to p\bar{p}}$ and ${J/\psi\to p\bar{p}}$ branching fractions, respectively.
Charmonium is a valuable probe in heavy-ion collisions to study the properties of the quark gluon plasma, and is also an interesting probe in small collision systems to study cold nuclear matter effects, which are also present in large collision systems. With the recent observations of collective behavior of produced particles in small system collisions, measurements of the modification of charmonium in small systems have become increasingly relevant. We present the results of J/ψ measurements at forward and backward rapidity in various small collision systems, p+p, p+Al, p+Au and 3He+Au, at √sNN =200 GeV. The results are presented in the form of the observable RAB, the nuclear modification factor, a measure of the ratio of the J/ψ invariant yield compared to the scaled yield in p+p collisions. We examine the rapidity, transverse momentum, and collision centrality dependence of nuclear effects on J/ψ production with different projectile sizes p and 3He, and different target sizes Al and Au. The modification is found to be strongly dependent on the target size, but to be very similar for p+Au and 3He+Au. However, for 0%–20% central collisions at backward rapidity, the modification for 3He+Au is found to be smaller than that for p+Au, with a mean fit to the ratio of 0.89±0.03(stat)±0.08(syst), possibly indicating final state effects due to the larger projectile size.
J/psi invariant yields in p+p collisions as a function of pT at forward and backward rapidity. The statistical and systematic uncertainties vary point-to-point and are listed for each measured value. An additional global systematic uncertainty is provided in each column heading, which applies to all data points per column.
J/psi nuclear modification in p+Al, p+Au and 3He+Au collisions as a function of centrality and rapidity. The statistical and systematic uncertainties vary point-to-point and are listed for each measured value. An additional global systematic uncertainty is provided in each column heading, which applies to all data points per column.
J/psi nuclear modification in p+Al collisions as a function of centrality and rapidity. The statistical and systematic uncertainties vary point-to-point and are listed for each measured value. An additional global systematic uncertainty is provided in each column heading, which applies to all data points per column.
A search for supersymmetric partners of gluons and quarks is presented, involving signatures with jets and either two isolated leptons (electrons or muons) with the same electric charge, or at least three isolated leptons. A data sample of proton-proton collisions at $\sqrt{s}$ = 13 TeV recorded with the ATLAS detector at the Large Hadron Collider between 2015 and 2018, corresponding to a total integrated luminosity of 139 fb$^{-1}$, is used for the search. No significant excess over the Standard Model expectation is observed. The results are interpreted in simplified supersymmetric models featuring both R-parity conservation and R-parity violation, raising the exclusion limits beyond those of previous ATLAS searches to 1600 GeV for gluino masses and 750 GeV for bottom and top squark masses in these scenarios.
Observed 95% CL exclusion contours in signal region Rpc2L0b on the gluino and lightest neutralino masses in a SUSY scenario where gluinos are produced in pairs and decay into the lightest neutralino via a two-steps cascade, $\tilde g \to q \bar{q}^{'} \tilde{\chi}_1^\pm$ followed by $\tilde{\chi}_1^\pm \to W^\pm \tilde{\chi}_2^0$ and $ \tilde{\chi}_2^0 \to Z \tilde{\chi}_1^0$.
Observed 95% CL exclusion contours in signal region Rpc2L0b on the gluino and lightest neutralino masses in a SUSY scenario where gluinos are produced in pairs and decay into the lightest neutralino via a two-steps cascade, $\tilde g \to q \bar{q}^{'} \tilde{\chi}_1^\pm$ followed by $\tilde{\chi}_1^\pm \to W^\pm \tilde{\chi}_2^0$ and $ \tilde{\chi}_2^0 \to Z \tilde{\chi}_1^0$.
Observed 95% CL exclusion contours in signal region Rpc2L0b on the gluino and lightest neutralino masses in a SUSY scenario where gluinos are produced in pairs and decay into the lightest neutralino via a two-steps cascade, $\tilde g \to q \bar{q}^{'} \tilde{\chi}_1^\pm$ followed by $\tilde{\chi}_1^\pm \to W^\pm \tilde{\chi}_2^0$ and $ \tilde{\chi}_2^0 \to Z \tilde{\chi}_1^0$.
The production of the $\Lambda$(1520) baryonic resonance has been measured at midrapidity in inelastic pp collisions at $\sqrt{s}$ = 7 TeV and in p-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV for non-single diffractive events and in multiplicity classes. The resonance is reconstructed through its hadronic decay channel $\Lambda$(1520) $\rightarrow$ pK$^{-}$ and the charge conjugate with the ALICE detector. The integrated yields and mean transverse momenta are calculated from the measured transverse momentum distributions in pp and p-Pb collisions. The mean transverse momenta follow mass ordering as previously observed for other hyperons in the same collision systems. A Blast-Wave function constrained by other light hadrons ($\pi$, K, K$_{\rm{S}}^0$, p, $\Lambda$) describes the shape of the $\Lambda$(1520) transverse momentum distribution up to 3.5 GeV/$c$ in p-Pb collisions. In the framework of this model, this observation suggests that the $\Lambda(1520)$ resonance participates in the same collective radial flow as other light hadrons. The ratio of the yield of $\Lambda(1520)$ to the yield of the ground state particle $\Lambda$ remains constant as a function of charged-particle multiplicity, suggesting that there is no net effect of the hadronic phase in p-Pb collisions on the $\Lambda$(1520) yield.
$p_{\rm T}$-differential yields of $\Lambda$(1520) (sum of particle and anti-particle states) at midrapidity in inelastic pp collisions at $\sqrt{s}$ $\mathrm{=}$ 7 TeV.
$p_{\rm T}$-differential yields of $\Lambda$(1520) (sum of particle and anti-particle states) in NSD p--Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ $\mathrm{=}$ 5.02 TeV. The uncertainty 'sys,$p_{\rm T}$-correlated' indicates the systematic uncertainty after removing the contributions of $p_{\rm T}$-uncorrelated uncertainty.
$p_{\rm T}$-differential yields of $\Lambda$(1520) (sum of particle and anti-particle states) in p--Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ $\mathrm{=}$ 5.02 TeV in multiplicity interval 0--20\%. The uncertainty 'sys,$p_{\rm T}$-correlated' indicates the systematic uncertainty after removing the contributions of $p_{\rm T}$-uncorrelated uncertainty.
The production cross-sections for $W^{\pm}$ and $Z$ bosons are measured using ATLAS data corresponding to an integrated luminosity of 4.0 pb$^{-1}$ collected at a centre-of-mass energy $\sqrt{s}=2.76$ TeV. The decay channels $W \rightarrow \ell \nu$ and $Z \rightarrow \ell \ell $ are used, where $\ell$ can be an electron or a muon. The cross-sections are presented for a fiducial region defined by the detector acceptance and are also extrapolated to the full phase space for the total inclusive production cross-section. The combined (average) total inclusive cross-sections for the electron and muon channels are: \begin{eqnarray} \sigma^{\text{tot}}_{W^{+}\rightarrow \ell \nu}& = & 2312 \pm 26\ (\text{stat.})\ \pm 27\ (\text{syst.}) \pm 72\ (\text{lumi.}) \pm 30\ (\text{extr.})\text{pb} \nonumber, \\ \sigma^{\text{tot}}_{W^{-}\rightarrow \ell \nu}& = & 1399 \pm 21\ (\text{stat.})\ \pm 17\ (\text{syst.}) \pm 43\ (\text{lumi.}) \pm 21\ (\text{extr.})\text{pb} \nonumber, \\ \sigma^{\text{tot}}_{Z \rightarrow \ell \ell}& = & 323.4 \pm 9.8\ (\text{stat.}) \pm 5.0\ (\text{syst.}) \pm 10.0\ (\text{lumi.}) \pm 5.5 (\text{extr.}) \text{pb} \nonumber. \end{eqnarray} Measured ratios and asymmetries constructed using these cross-sections are also presented. These observables benefit from full or partial cancellation of many systematic uncertainties that are correlated between the different measurements.
Measured fiducial cross section times leptonic branching ratio for W+ production in the W+ -> e+ nu final state.
Measured fiducial cross section times leptonic branching ratio for W+ production in the W+ -> mu+ nu final state.
Measured fiducial cross section times leptonic branching ratio for W- production in the W- -> e- nu final state.
This paper presents measurements of the $W^+ \rightarrow \mu^+\nu$ and $W^- \rightarrow \mu^-\nu$ cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of $20.2~\mbox{fb$^{-1}$}$. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.
The correction factors, $C_{W^±,i}$ with their associated systematic uncertainties as a function of $|\eta_{\mu}|$, for $W^+$ and $W^−$
The integrated global correction factor $C_{W^±}$, for $W^+$ and $W^−$
Cross-sections (differential in $\eta_{\mu}$) and asymmetry, as a function of $|\eta_{\mu}|$). The central values are provided along with the statistical and dominant systematic uncertainties: the data statistical uncertainty (Data Stat.), the $E_T^{\textrm{miss}}$ uncertainty, the uncertainties related to muon reconstruction (Muon Reco.), those related to the background, those from MC statistics (MC Stat.), and modelling uncertainties. The uncertainties of the cross-sections are given in percent and those of the asymmetry as an absolute difference from the nominal.
The inclusive production rates of isolated, prompt photons in $p$+Pb collisions at $\sqrt{s_\mathrm{NN}} = 8.16$ TeV are studied with the ATLAS detector at the Large Hadron Collider using a dataset with an integrated luminosity of 165 nb$^{-1}$ recorded in 2016. The cross-section and nuclear modification factor $R_{p\mathrm{Pb}}$ are measured as a function of photon transverse energy from 20 GeV to 550 GeV and in three nucleon-nucleon centre-of-mass pseudorapidity regions, (-2.83,-2.02), (-1.84,0.91), and (1.09,1.90). The cross-section and $R_{p\mathrm{Pb}}$ values are compared with the results of a next-to-leading-order perturbative QCD calculation, with and without nuclear parton distribution function modifications, and with expectations based on a model of the energy loss of partons prior to the hard scattering. The data disfavour a large amount of energy loss and provide new constraints on the parton densities in nuclei.
The measured cross sections for prompt, isolated photons with rapidity in (1.09,1.90).
The measured cross sections for prompt, isolated photons with rapidity in (−1.84,0.91).
The measured cross sections for prompt, isolated photons with rapidity in (−2.83,−2.02).
Inclusive and differential cross-sections for the production of a top-quark pair in association with a photon are measured with proton-proton collision data corresponding to an integrated luminosity of 36.1 fb$^{-1}$, collected by the ATLAS detector at the LHC in 2015 and 2016 at a centre-of-mass energy of 13 TeV. The measurements are performed in single-lepton and dilepton final states in a fiducial volume. Events with exactly one photon, one or two leptons, a channel-dependent minimum number of jets, and at least one $b$-jet are selected. Neural network algorithms are used to separate the signal from the backgrounds. The fiducial cross-sections are measured to be 521 $\pm$ 9(stat.) $\pm$ 41(sys.) fb and 69 $\pm$ 3(stat.) $\pm$ 4(sys.) fb for the single-lepton and dilepton channels, respectively. The differential cross-sections are measured as a function of photon transverse momentum, photon absolute pseudorapidity, and angular distance between the photon and its closest lepton in both channels, as well as azimuthal opening angle and absolute pseudorapidity difference between the two leptons in the dilepton channel. All measurements are in agreement with the theoretical predictions.
The measured fiducial cross section in the single lepton channel. The first uncertainty is the statistical uncertainty and the second one is the systematic uncertainty.
The measured fiducial cross section in the dilepton channel. The first uncertainty is the statistical uncertainty and the second one is the systematic uncertainty.
The measured normalized differential cross section as a function of the photon pT in the single lepton channel. The uncertainty is decomposed into five components which are the signal modelling uncertainty, the experimental uncertainty, the ttbar modelling uncertainty, the other background estimation uncertainty, and the data statistical uncertainty.
This Letter presents a search for the production of a long-lived neutral particle ($Z_d$) decaying within the ATLAS hadronic calorimeter, in association with a Standard Model (SM) $Z$ boson produced via an intermediate scalar boson, where $Z\to l^+l^-$ ($l=e,\mu$). The data used were collected by the ATLAS detector during 2015 and 2016 $pp$ collisions with a center-of-mass energy of $\sqrt{s} = 13$ TeV at the Large Hadron Collider and corresponds to an integrated luminosity of $36.1\pm0.8$ fb$^{-1}$. No significant excess of events is observed above the expected background. Limits on the production cross section of the scalar boson times its decay branching fraction into the long-lived neutral particle are derived as a function of the mass of the intermediate scalar boson, the mass of the long-lived neutral particle, and its $c\tau$ from a few centimeters to one hundred meters. In the case that the intermediate scalar boson is the SM Higgs boson, its decay branching fraction to a long-lived neutral particle with a $c\tau$ approximately between 0.1 m and 7 m is excluded with a 95% confidence level up to 10% for $m_{Z_d}$ between 5 and 15 GeV.
The product of acceptance and efficiency for all signal MC samples.
The production of $\Upsilon (nS)$ mesons ($n=1,2,3$) in $p$Pb and Pb$p$ collisions at a centre-of-mass energy per nucleon pair $\sqrt{s_{NN}}=8.16$ TeV is measured by the LHCb experiment, using a data sample corresponding to an integrated luminosity of 31.8 nb$^{-1}$. The $\Upsilon (nS)$ mesons are reconstructed through their decays into two opposite-sign muons. The measurements comprise the differential production cross-sections of the $\Upsilon (1S)$ and $\Upsilon (2S)$ states, their forward-to-backward ratios and nuclear modification factors, performed as a function of the transverse momentum $p_{\mathrm{T}}$ and rapidity in the nucleon-nucleon centre-of-mass frame $y^*$ of the $\Upsilon (nS)$ states, in the kinematic range $p_{\rm{T}}<25$ GeV/$c$ and $1.5<y^*<4.0$ ($-5.0<y^*<-2.5$) for $p$Pb (Pb$p$) collisions. In addition, production cross-sections for $\Upsilon (3S)$ are measured integrated over phase space and the production ratios between all three $\Upsilon (nS)$ states are determined. The measurements are compared to theoretical predictions and suppressions for quarkonium in $p$Pb collisions are observed.
$\Upsilon(1S)$ production cross-section in $p$Pb, as a function of $p_{T}$ and $y*$. The uncertainty is the sum in quadrature of the statistical and systematic components.
$\Upsilon(1S)$ production cross-section in Pb$p$, as a function of $p_{T}$ and $y^*$. The uncertainty is the sum in quadrature of the statistical and systematic components.
$\Upsilon(1S)$ production cross-section in $p$Pb and Pb$p$, as a function of $p_{T}$. The uncertainty is the sum in quadrature of the statistical and systematic components.
The inclusive $D_s^{\pm}$ production asymmetry is measured in $pp$ collisions collected by the LHCb experiment at centre-of-mass energies of $\sqrt{s} =7$ and 8 TeV. Promptly produced $D_s^{\pm}$ mesons are used, which decay as $D_s^{\pm}\to\phi\pi^{\pm}$, with $\phi\to K^+K^-$. The measurement is performed in bins of transverse momentum, $p_{\rm T}$, and rapidity, $y$, covering the range $2.5
Values of the $D_s^+$ production asymmetry in percent, including, respectively, the statistical and systematic uncertainties for each of the $D_s^+$ kinematic bins using the combined $\sqrt{s} =7$ and 8 TeV data sets. The statistical and systematic uncertainties include the corresponding contributions from the detection asymmetries, and are therefore correlated between the bins. ASYM is defined as ASYM = ((SIG(D/S+)-SIG(D/S-))/(SIG(D/S+)+SIG(D/S+)).
Values of the $D_s^+$ production asymmetry in percent, including, respectively, the statistical and systematic uncertainties for each of the $D_s^+$ kinematic bins using the $\sqrt{s} =7$ TeV data set. The statistical and systematic uncertainties include the corresponding contributions from the detection asymmetries, and are therefore correlated between the bins. ASYM is defined as ASYM = ((SIG(D/S+)-SIG(D/S-))/(SIG(D/S+)+SIG(D/S+)).
Values of the $D_s^+$ production asymmetry in percent, including, respectively, the statistical and systematic uncertainties for each of the $D_s^+$ kinematic bins using the $\sqrt{s} =8$ TeV data set. The statistical and systematic uncertainties include the corresponding contributions from the detection asymmetries, and are therefore correlated between the bins. ASYM is defined as ASYM = ((SIG(D/S+)-SIG(D/S-))/(SIG(D/S+)+SIG(D/S+)).
The production cross-sections of $\Upsilon(1S)$, $\Upsilon(2S)$ and $\Upsilon(3S)$ mesons in proton-proton collisions at $\sqrt{s}$= 13 TeV are measured with a data sample corresponding to an integrated luminosity of $277 \pm 11$ $\rm pb^{-1}$ recorded by the LHCb experiment in 2015. The $\Upsilon$ mesons are reconstructed in the decay mode $\Upsilon\to\mu^{+}\mu^{-}$. The differential production cross-sections times the dimuon branching fractions are measured as a function of the $\Upsilon$ transverse momentum, $p_{\rm T}$, and rapidity, $y$, over the range $0 < p_{\rm T}< 30$ GeV/c and $2.0 < y < 4.5$. The ratios of the cross-sections with respect to the LHCb measurement at $\sqrt{s}$= 8 TeV are also determined. The measurements are compared with theoretical predictions based on NRQCD.
Double-differential cross-sections times dimuon branching fraction in different bins of $p_T$ and $y$ for $\Upsilon$(1S) (in pb). The first uncertainty is statistical and the second is systematic.
Double-differential cross-sections times dimuon branching fraction in different bins of $p_T$ and $y$ for $\Upsilon$(2S) (in pb). The first uncertainty is statistical and the second is systematic.
Double-differential cross-sections times dimuon branching fraction in different bins of $p_T$ and $y$ for $\Upsilon$(3S) (in pb). The first uncertainty is statistical and the second is systematic.
Forward top quark pair production is studied in $pp$ collisions in the $\mu eb$ final state using a data sample corresponding to an integrated luminosity of 1.93 fb$^{-1}$ collected with the LHCb experiment at a centre-of-mass energy of 13 TeV. The cross-section is measured in a fiducial region where both leptons have a transverse momentum greater than 20 GeV and a pseudorapidity between 2.0 and 4.5. The quadrature sum of the azimuthal separation and the difference in pseudorapidities, denoted $\Delta R$, between the two leptons must be larger than 0.1. The $b$-jet axis is required to be separated from both leptons by a $\Delta R$ of 0.5, and to have a transverse momentum in excess of 20 GeV and a pseudorapidity between 2.2 and 4.2. The cross-section is measured to be $$\sigma_{t\bar{t}}= 126\pm19\,(\mathrm{stat})\pm16\,(\mathrm{syst})\pm5\,(\mathrm{lumi})\,\,\mathrm{ fb}$$ where the first uncertainty is statistical, the second is systematic, and the third is due to the luminosity determination. The measurement is compatible with the Standard Model prediction.
The measured fiducial cross section. The uncertainty is split into statistical, systematic and uncertainty due to luminosity.
The inclusive and fiducial $t\bar{t}$ production cross-sections are measured in the lepton+jets channel using 20.2 fb$^{-1}$ of proton-proton collision data at a centre-of-mass energy of 8 TeV recorded with the ATLAS detector at the LHC. Major systematic uncertainties due to the modelling of the jet energy scale and $b$-tagging efficiency are constrained by separating selected events into three disjoint regions. In order to reduce systematic uncertainties in the most important background, the W+jets process is modelled using Z+jets events in a data-driven approach. The inclusive $t\bar{t}$ cross-section is measured with a precision of 5.7% to be $\sigma_{\text{inc}}(t\bar{t})$ = 248.3 $\pm$ 0.7 (stat.) $\pm$ 13.4 (syst.) $\pm$ 4.7 (lumi.) pb, assuming a top-quark mass of 172.5 GeV. The result is in agreement with the Standard Model prediction. The cross-section is also measured in a phase space close to that of the selected data. The fiducial cross-section is $\sigma_{\text{fid}}(t\bar{t})$ = 48.8 $\pm$ 0.1 (stat.) $\pm$ 2.0 (syst.) $\pm$ 0.9 (lumi.) pb with a precision of 4.5%.
The measured inclusive cross section. The first systematic uncertainty (sys_1) is the combined systematic uncertainty excluding luminosity, the second (sys_2) is the luminosity
The measured fiducial cross section. The first systematic uncertainty (sys_1) is the combined systematic uncertainty excluding luminosity, the second (sys_2) is the luminosity
Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses proton--proton collision data corresponding to an integrated luminosity of 36.1 fb${}^{-1}$ at a centre-of-mass energy of 13 TeV collected in 2015 and 2016 with the ATLAS detector at the Large Hadron Collider. Events are required to have at least one jet with a transverse momentum above 250 GeV and no leptons ($e$ or $\mu$). Several signal regions are considered with increasing requirements on the missing transverse momentum above 250 GeV. Good agreement is observed between the number of events in data and Standard Model predictions. The results are translated into exclusion limits in models with pair-produced weakly interacting dark-matter candidates, large extra spatial dimensions, and supersymmetric particles in several compressed scenarios.
The measured leading jet $p_{T}$ distribution in the W($\rightarrow \mu \nu$)+jets control region, for the $E_{T}^{miss}$ > 250GeV inclusive selection, compared to the background predictions. The latter include the global normalization factors extracted from the fit. The last bin of the distribution contains overflows.
The measured $E_{T}^{miss}$ distribution in the W($\rightarrow e \nu$)+jets control region, for the $E_{T}^{miss}$ > 250GeV inclusive selection, compared to the background predictions. The latter include the global normalization factors extracted from the fit. The last bin of the distribution contains overflows.
The measured leading jet $p_{T}$ distribution in the W($\rightarrow e \nu$)+jets control region, for the $E_{T}^{miss}$ > 250GeV inclusive selection, compared to the background predictions. The latter include the global normalization factors extracted from the fit. The last bin of the distribution contains overflows.
This paper presents a measurement of the $W$ boson production cross section and the $W^{+}/W^{-}$ cross-section ratio, both in association with jets, in proton--proton collisions at $\sqrt{s}=8$ TeV with the ATLAS experiment at the Large Hadron Collider. The measurement is performed in final states containing one electron and missing transverse momentum using data corresponding to an integrated luminosity of 20.2 fb$^{-1}$. Differential cross sections for events with one or two jets are presented for a range of observables, including jet transverse momenta and rapidities, the scalar sum of transverse momenta of the visible particles and the missing transverse momentum in the event, and the transverse momentum of the $W$ boson. For a subset of the observables, the differential cross sections of positively and negatively charged $W$ bosons are measured separately. In the cross-section ratio of $W^{+}/W^{-}$ the dominant systematic uncertainties cancel out, improving the measurement precision by up to a factor of nine. The observables and ratios selected for this paper provide valuable input for the up quark, down quark, and gluon parton distribution functions of the proton.
Cross section for the production of W bosons for different inclusive jet multiplicities.
Statistical correlation between bins in data for the cross section for the production of W bosons for different inclusive jet multiplicities.
Differential cross sections for the production of W<sup>+</sup> bosons, W<sup>-</sup> bosons and the W<sup>+</sup>/W<sup>-</sup> cross section ratio as a function of the inclusive jet multiplicity.
Inclusive jet and dijet cross-sections are measured in proton-proton collisions at a centre-of-mass energy of 13 TeV. The measurement uses a dataset with an integrated luminosity of 3.2 fb$^{-1}$ recorded in 2015 with the ATLAS detector at the Large Hadron Collider. Jets are identified using the anti-${k_t}$ algorithm with a radius parameter value of $R=0.4$. The inclusive jet cross-sections are measured double-differentially as a function of the jet transverse momentum, covering the range from 100 GeV to 3.5 TeV, and the absolute jet rapidity up to $|y|=3$. The double-differential dijet production cross-sections are presented as a function of the dijet mass, covering the range from 300 GeV to 9 TeV, and the half absolute rapidity separation between the two leading jets within $|y|<3$, $y*$, up to $y*=3$. Next-to-leading-order, and next-to-next-to-leading-order for the inclusive jet measurement, perturbative QCD calculations corrected for non-perturbative and electroweak effects are compared to the measured cross-sections.
rapidity bin 0 < |Y| < 0.5 anti-kt R=0.4
rapidity bin 0.5 < |Y| < 1.0 anti-kt R=0.4
rapidity bin 1.0 < |Y| < 1.5 anti-kt R=0.4
This Letter presents the measurement of differential cross sections of isolated prompt photons produced in association with a b-jet or a c-jet. These final states provide sensitivity to the heavy-flavour content of the proton and aspects related to the modelling of heavy-flavour quarks in perturbative QCD. The measurement uses proton-proton collision data at a centre-of-mass energy of 8 TeV recorded by the ATLAS detector at the LHC in 2012 corresponding to an integrated luminosity of up to 20.2 fb$^{-1}$. The differential cross sections are measured for each jet flavour with respect to the transverse energy of the leading photon in two photon pseudorapidity regions: $|\eta^\gamma|<1.37$ and $1.56<|\eta^\gamma|<2.37$. The measurement covers photon transverse energies $25 < E_\textrm{T}^\gamma<400$ GeV and $25 < E_\textrm{T}^\gamma<350$ GeV respectively for the two $|\eta^\gamma|$ regions. For each jet flavour, the ratio of the cross sections in the two $|\eta^\gamma|$ regions is also measured. The measurement is corrected for detector effects and compared to leading-order and next-to-leading-order perturbative QCD calculations, based on various treatments and assumptions about the heavy-flavour content of the proton. Overall, the predictions agree well with the measurement, but some deviations are observed at high photon transverse energies. The total uncertainty in the measurement ranges between 13% and 66%, while the central $\gamma+b$ measurement exhibits the smallest uncertainty, ranging from 13% to 27%, which is comparable to the precision of the theoretical predictions.
Measured fiducial integrated $\gamma+b$ and $\gamma+c$ cross sections for $|\eta^\gamma|<1.37$ and $1.56<|\eta^\gamma|<2.37$.
Measured $\gamma+b$ fiducial differential cross section as a function of $E_\text{T}^\gamma$ for $|\eta^\gamma|<1.37$.
Measured $\gamma+b$ fiducial differential cross section as a function of $E_\text{T}^\gamma$ for $1.56<|\eta^\gamma|<2.37$.
A search for heavy neutral Higgs bosons and $Z^{\prime}$ bosons is performed using a data sample corresponding to an integrated luminosity of 36.1 fb$^{-1}$ from proton-proton collisions at $\sqrt{s}$ = 13 TeV recorded by the ATLAS detector at the LHC during 2015 and 2016. The heavy resonance is assumed to decay to $\tau^+\tau^-$ with at least one tau lepton decaying to final states with hadrons and a neutrino. The search is performed in the mass range of 0.2-2.25 TeV for Higgs bosons and 0.2-4.0 TeV for $Z^{\prime}$ bosons. The data are in good agreement with the background predicted by the Standard Model. The results are interpreted in benchmark scenarios. In the context of the hMSSM scenario, the data exclude $\tan\beta > 1.0$ for $m_A$ = 0.25 TeV and $\tan\beta > 42$ for $m_A$ = 1.5 TeV at the 95% confidence level. For the Sequential Standard Model, $Z^{\prime}_\mathrm{SSM}$ with $m_{Z^{\prime}} < 2.42$ TeV is excluded at 95% confidence level, while $Z^{\prime}_\mathrm{NU}$ with $m_{Z^{\prime}} < 2.25$ TeV is excluded for the non-universal $G(221)$ model that exhibits enhanced couplings to third-generation fermions.
Observed and predicted mTtot distribution in the b-veto category of the 1l1tau_h channel. Despite listing this as an exclusive final state (as there must be no b-jets), there is no explicit selection on the presence of additional light-flavour jets. Please note that the bin content is divided by the bin width in the paper figure, but not in the HepData table. In the paper, the first bin is cut off at 60 GeV for aesthetics but contains underflows down to 50 GeV as in the HepData table. The last bin includes overflows. The combined prediction for A and H bosons with masses of 300, 500 and 800 GeV and $\tan\beta$ = 10 in the hMSSM scenario are also provided.
Observed and predicted mTtot distribution in the b-tag category of the 1l1tau_h channel. Despite listing this as an exclusive final state (as there must be at least one b-jets), there is no explicit selection on the presence of additional light-flavour jets. Please note that the bin content is divided by the bin width in the paper figure, but not in the HepData table. In the paper, the first bin is cut off at 60 GeV for aesthetics but contains underflows down to 50 GeV as in the HepData table. The last bin includes overflows. The combined prediction for A and H bosons with masses of 300, 500 and 800 GeV and $\tan\beta$ = 10 in the hMSSM scenario are also provided.
Observed and predicted mTtot distribution in the b-veto category of the 2tau_h channel. Despite listing this as an exclusive final state (as there must be no b-jets), there is no explicit selection on the presence of additional light-flavour jets. Please note that the bin content is divided by the bin width in the paper figure, but not in the HepData table. The last bin includes overflows. The combined prediction for A and H bosons with masses of 300, 500 and 800 GeV and $\tan\beta$ = 10 in the hMSSM scenario are also provided.
The polarization of the $\Upsilon(1S)$, $\Upsilon(2S)$ and $\Upsilon(3S) $mesons, produced in $pp$ collisions at centre-of-mass energies $\sqrt{s}$=7 and 8TeV, is measured using data samples collected by the LHCb experiment, corresponding to integrated luminosities of 1 and 2fb$^{-1}$, respectively. The measurements are performed in three polarization frames, using $\Upsilon\to\mu^+\mu^-$ decays in the kinematic region of the transverse momentum $p_{T}(\Upsilon)<30GeV/c$, and rapidity $2.2<y(\Upsilon)<4.5$. No large polarization is observed.
The polarization parameter $\lambda_{\theta}$ measured in the helicity frame for the $\Upsilon(1S)$ state in different bins of $p_{T}^{\Upsilon}$ and three rapidity ranges using data collected at $\sqrt{s}=7\,\mathrm{TeV}$. The first uncertainty is statistical and the second is systematic.
The polarization parameter $\lambda_{\theta\phi}$ measured in the helicity frame for the $\Upsilon(1S)$ state in different bins of $p_{T}^{\Upsilon}$ and three rapidity ranges using data collected at $\sqrt{s}=7\,\mathrm{TeV}$. The first uncertainty is statistical and the second represents the systematic uncertainty.
The polarization parameter $\lambda_{\phi}$ measured in the helicity frame for the $\Upsilon(1S)$ state in different bins of $p_{T}^{\Upsilon}$ and three rapidity ranges using data collected at $\sqrt{s}=7\,\mathrm{TeV}$. The first uncertainty is statistical and the second is systematic.
Final results are presented from the inclusive measurement of deep-inelastic polarised-muon scattering on longitudinally polarised deuterons using a $^6$LiD target. The data were taken at $160~{\rm GeV}$ beam energy and the results are shown for the kinematic range $1~({\rm GeV}/c)^2 < Q^2 < 100~({\rm GeV}/c)^2$ in photon virtuality, $0.004<x<0.7$ in the Bjorken scaling variable and $W > 4~{\rm GeV}/c^2$ in the mass of the hadronic final state. The deuteron double-spin asymmetry $A_1^{\rm d}$ and the deuteron longitudinal-spin structure function $g_1^{\rm d}$ are presented in bins of $x$ and $Q^2$. Towards lowest accessible values of $x$, $g_1^{\rm d}$ decreases and becomes consistent with zero within uncertainties. The presented final $g_1^{\rm d}$ values together with the recently published final $g_1^{\rm p}$ values of COMPASS are used to again evaluate the Bjorken sum rule and perform the QCD fit to the $g_1$ world data at next-to-leading order of the strong coupling constant. In both cases, changes in central values of the resulting numbers are well within statistical uncertainties. The flavour-singlet axial charge $a_0$, {which is identified in the $\overline{\rm MS}$ renormalisation scheme with the total contribution of quark helicities to the nucleon spin}, is extracted from only the COMPASS deuteron data with negligible extrapolation uncertainty: $a_0 (Q^2 = 3~({\rm GeV}/c)^2) = 0.32 \pm 0.02_{\rm stat} \pm0.04_{\rm syst} \pm 0.05_{\rm evol}$. Together with the recent results on the proton spin structure function $g_1^{\rm p}$, the results on $g_1^{\rm d}$ constitute the COMPASS legacy on the measurements of $g_1$ through inclusive spin-dependent deep inelastic scattering.
Values of $A_1^d$ and $g_1^d$ for the COMPASS deuteron data at 160 GeV in $x$ bins averaged over $Q^2$.
Values of $A_1^d$ and $g_1^d$ for the COMPASS deuteron data at 160 GeV in (x, $Q^2$) bins.
Values of $g_1^{NS}$ for the COMPASS data in $x$ bins averaged over $Q^2$.
We report the first measurement of the longitudinal double-spin asymmetry $A_{LL}$ for mid-rapidity di-jet production in polarized $pp$ collisions at a center-of-mass energy of $\sqrt{s} = 200$ GeV. The di-jet cross section was measured and is shown to be consistent with next-to-leading order (NLO) perturbative QCD predictions. $A_{LL}$ results are presented for two distinct topologies, defined by the jet pseudorapidities, and are compared to predictions from several recent NLO global analyses. The measured asymmetries, the first such correlation measurements, support those analyses that find positive gluon polarization at the level of roughly 0.2 over the region of Bjorken-$x > 0.05$.
Data simulation comparison (with arbitrary normalization). Di-jet invariant mass.
Data simulation comparison (with arbitrary normalization). Difference between jet pseudorapidities.
Data simulation comparison (with arbitrary normalization). Difference between jet azimuthal angles.
Production cross-sections of prompt charm mesons are measured using data from $pp$ collisions at the LHC at a centre-of-mass energy of $5\,$TeV. The data sample corresponds to an integrated luminosity of $8.60\pm0.33\,$pb$^{-1}$ collected by the LHCb experiment. The production cross-sections of $D^0$, $D^+$, $D_s^+$, and $D^{*+}$ mesons are measured in bins of charm meson transverse momentum, $p_{\text{T}}$, and rapidity, $y$. They cover the rapidity range $2.0<y<4.5$ and transverse momentum ranges $0 < p_{\text{T}} < 10\, \text{GeV}/c$ for $D^0$ and $D^+$ and $1 < p_{\text{T}} < 10\, \text{GeV}/c$ for $D_s^+$ and $D^{*+}$ mesons. The inclusive cross-sections for the four mesons, including charge-conjugate states, within the range of $1 < p_{\text{T}} < 8\, \text{GeV}/c$ are determined to be \sigma(pp\rightarrow D^0 X) = 1004 \pm 3 \pm 54\,\mu\text{b} \sigma(pp\rightarrow D^+ X) = 402 \pm 2 \pm 30\,\mu\text{b} \sigma(pp\rightarrow D_s^+ X) = 170 \pm 4 \pm 16\,\mu\text{b} \sigma(pp\rightarrow D^{*+} X)= 421 \pm 5 \pm 36\,\mu\text{b} where the uncertainties are statistical and systematic, respectively.
Differential production cross-sections for prompt $D^{0} + \bar{D}^{0}$ mesons in bins of $(p_{\mathrm{T}}, y)$. The first uncertainty is statistical, and the second is the total systematic.
Differential production cross-sections for prompt $D^{0} + \bar{D}^{0}$ mesons in bins of $(p_{\mathrm{T}}, y)$. The first uncertainty is statistical, and the second is the total systematic.
Differential production cross-sections for prompt $D^{+} + D^{-}$ mesons in bins of $(p_{\mathrm{T}}, y)$. The first uncertainty is statistical, and the second is the total systematic.
Measurements of the differential branching fraction and angular moments of the decay $B^0 \to K^+ \pi^- \mu^+ \mu^-$ in the $K^+\pi^-$ invariant mass range $1330<m(K^+ \pi^-)<1530~MeV/c^2$ are presented. Proton-proton collision data are used, corresponding to an integrated luminosity of 3 $fb^{-1}$ collected by the LHCb experiment. Differential branching fraction measurements are reported in five bins of the invariant mass squared of the dimuon system, $q^2$, between 0.1 and 8.0 $GeV^2/c^4$. For the first time, an angular analysis sensitive to the S-, P- and D-wave contributions of this rare decay is performed. The set of 40 normalised angular moments describing the decay is presented for the $q^2$ range 1.1--6.0 $GeV^2/c^4$.
: Differential branching fraction of $B^0 \to K^+ \pi^- \mu^+ \mu^-$ in bins of $q^2$ for the range $1330<m(K^+ \pi^-)<1530~MeV/c^2$. The first uncertainty is statistical, the second systematic and the third due to the uncertainty on the $B^0 \to J/\psi K^*(892)^0$ and $J/\psi \to \mu\mu$ branching fractions.
Measurement of the normalised moments, $\overline{\Gamma}_{i}$, of the decay $B^0 \to K^+ \pi^- \mu^+ \mu^-$ in the range $1.1< q^2<6.0 GeV^2/c^4$ and $1330<m(K^+ \pi^-)<1530~MeV/c^2$. The first uncertainty is statistical and the second systematic.
Full covariance matrix of the normalised moments. The statistical and systematic uncertainties are combined.
We present measurements of two-particle correlations with neutral pion trigger particles of transverse momenta $8 < p_{\mathrm{T}}^{\rm trig} < 16~\mathrm{GeV}/c$ and associated charged particles of $0.5 < p_{\mathrm{T}}^{\rm assoc} < 10~\mathrm{GeV}/c$ versus the azimuthal angle difference $\Delta\varphi$ at midrapidity in pp and central Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV with ALICE. The new measurements exploit associated charged hadrons down to $0.5~\mathrm{GeV}/c$, which significantly extends our previous measurement that only used charged hadrons above $3~\mathrm{GeV}/c$. After subtracting the contributions of the flow background, $v_2$ to $v_5$, the per-trigger yields are extracted for $|\Delta\varphi|<0.7$ on the near and for $|\Delta\varphi-\pi| < 1.1$ on the away side. The ratio of per-trigger yields in Pb--Pb to those in pp collisions, $I_{\mathrm{AA}}$, is measured on the near and away side for the $0$--$10$\% most central Pb--Pb collisions. On the away side, the per-trigger yields in Pb--Pb are strongly suppressed to the level of $I_{\mathrm{AA}} \approx 0.6$ for $p_{\mathrm{T}}^{\rm assoc} > 3~\mathrm{GeV}/c$, while with decreasing momenta an enhancement develops reaching about $5$ at low $p_{\mathrm{T}}^{\rm assoc}$. On the near side, an enhancement of $I_{\mathrm{AA}}$ between $1.2$ at the highest to $1.8$ at the lowest $p_{\mathrm{T}}^{\rm assoc}$ is observed. The data are compared to parton-energy-loss predictions of the JEWEL and AMPT event generators, as well as to a perturbative QCD calculation with medium-modified fragmentation functions. All calculations qualitatively describe the away-side suppression at high $p_{\mathrm{T}}^{\rm assoc}$. Only AMPT captures the enhancement at low $p_{\mathrm{T}}^{\rm assoc}$, both on the near and away side. However, it also underpredicts $I_{\mathrm{AA}}$ above $5$ GeV/$c$, in particular on the near-side.
Charged-particle associated yields relative to $\pi^{0}$ trigger particles versus $\Delta\varphi$ in pp collisions at $\sqrt{s_{NN}}$=2.76 TeV. The $\pi^{0}$ trigger momentum range is $8< p_{T}^{trig} < 16~GeV/c$, and associated charged particle ranges are $0.5 < p_{T}^{assoc} < 1$, $1 < p_{T}^{assoc} < 2$, $2 < p_{T}^{assoc} < 4$ and $4 < p_{T}^{assoc} < 6~GeV/c$.
Charged-particle associated yields relative to $\pi^{0}$ trigger particles versus $\Delta\varphi$ in Pb-Pb collisions at $\sqrt{s_{NN}}$=2.76 TeV. The $\pi^{0}$ trigger momentum range is $8< p_{T}^{trig} < 16~GeV/c$, and associated charged particle ranges are $0.5 < p_{T}^{assoc} < 1$, $1 < p_{T}^{assoc} < 2$, $2 < p_{T}^{assoc} < 4$ and $4 < p_{T}^{assoc} < 6~GeV/c$.
Per-trigger yield modification, $I_{\rm AA}$, on the near side with trigger $\pi^{0}$ particle at $8 < p_{T}^{trig} < 16~GeV/c$ for $0$-$10$$\%$ Pb-Pb collisions at $\sqrt{s_{NN}}$= 2.76 TeV.