The differential cross sections for the elastic scattering of π+, π−, K+, K−, p, and p¯ on protons have been measured in the t interval -0.04 to -0.75 GeV2 at five momenta: 50, 70, 100, 140, and 175 GeV/c. The t distributions have been parametrized by the quadratic exponential form dσdt=Aexp(B|t|+C|t|2) and the energy dependence has been described in terms of a single-pole Regge model. The pp and K+p diffraction peaks are found to shrink with α′∼0.20 and ∼0.15 GeV−2, respectively. The p¯p diffraction peak is antishrinking while π±p and K−p are relatively energy-independent. Total elastic cross sections are calculated by integrating the differential cross sections. The rapid decline in σel observed at low energies has stopped and all six reactions approach relatively constant values of σel. The ratio of σelσtot approaches a constant value for all six reactions by 100 GeV, consistent with the predictions of the geometric-scaling hypothesis. This ratio is ∼0.18 for pp and p¯p, and ∼0.12-0.14 for π±p and K±p. A crossover is observed between K+p and K−p scattering at |t|∼0.19 GeV2, and between pp and p¯p at |t|∼0.11 GeV2. Inversion of the cross sections into impact-parameter space shows that protons are quite transparent to mesons even in head-on collisions. The probability for a meson to pass through a proton head-on without interaction inelastically is ∼20% while it is only ∼6% for an incident proton or antiproton. Finally, the results are compared with various quark-model predictions.
No description provided.
No description provided.
No description provided.
The ratio of π+p to pp elastic scattering is found to be smoothly varying over the range −t=0.03 to 0.4 GeV2. It is well fitted by a single exponential, indicating the forward behavior must be quite similar for the two reactions.
ACTUALLY THE DATA ARE THE EXPONENTIAL SLOPE OF THE RATIO OF D(SIG)/DT FOR THE TWO REACTIONS.
We report a null search for neutral heavy leptons produced unaccompanied by muons in 400-GeV/c proton-nucleon collisions in a magnetized beam dump and decaying in vacuum downstream. The upper limit on σB for L0's with Feynman x≳0.2 and θlab≲10 mrad with branching ratio B into two charged particles is σB≲2.8×10−35 cm2/nucleon at the 90% confidence level for masses below 1.0 GeV/c2 and lifetimes between 10−10 and 10−8 sec.
No description provided.
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.
This paper presents a statistical combination of searches targeting final states with two top quarks and invisible particles, characterised by the presence of zero, one or two leptons, at least one jet originating from a $b$-quark and missing transverse momentum. The analyses are searches for phenomena beyond the Standard Model consistent with the direct production of dark matter in $pp$ collisions at the LHC, using 139 fb$^{-\text{1}}$ of data collected with the ATLAS detector at a centre-of-mass energy of 13 TeV. The results are interpreted in terms of simplified dark matter models with a spin-0 scalar or pseudoscalar mediator particle. In addition, the results are interpreted in terms of upper limits on the Higgs boson invisible branching ratio, where the Higgs boson is produced according to the Standard Model in association with a pair of top quarks. For scalar (pseudoscalar) dark matter models, with all couplings set to unity, the statistical combination extends the mass range excluded by the best of the individual channels by 50 (25) GeV, excluding mediator masses up to 370 GeV. In addition, the statistical combination improves the expected coupling exclusion reach by 14% (24%), assuming a scalar (pseudoscalar) mediator mass of 10 GeV. An upper limit on the Higgs boson invisible branching ratio of 0.38 (0.30$^{+\text{0.13}}_{-\text{0.09}}$) is observed (expected) at 95% confidence level.
Post-fit signal region yields for the tt0L-high and the tt0L-low analyses. The bottom panel shows the statistical significance of the difference between the SM prediction and the observed data in each region. '$t\bar{t}$ (other)' represents $t\bar{t}$ events without extra jets or events with extra light-flavour jets. 'Other' includes contributions from $t\bar{t}W$, $tZ$ and $tWZ$ processes. The total uncertainty in the SM expectation is represented with hatched bands and the expected distributions for selected signal models are shown as dashed lines.
Representative fit distribution in the signal region for the tt1L analysis: each bin of such distribution corresponds to a single SR included in the fit. 'Other' includes contributions from $t\bar{t}W$, $tZ$, $tWZ$ and $t\bar{t}$ (semileptonic) processes. The total uncertainty in the SM expectation is represented with hatched bands and the expected distributions for selected signal models are shown as dashed lines.
Representative fit distribution in the same flavour leptons signal region for the tt2L analysis: each bin of such distribution, starting from the red arrow, corresponds to a single SR included in the fit. 'FNP' includes the contribution from fake/non-prompt lepton background arising from jets (mainly $\pi/K$, heavy-flavour hadron decays and photon conversion) misidentified as leptons, estimated in a purely data-driven way. 'Other' includes contributions from $t\bar{t}W$, $tZ$ and $tWZ$ processes. The total uncertainty in the SM expectation is represented with hatched bands and the expected distributions for selected signal models are shown as dashed lines.
Cross-section measurements for a $Z$ boson produced in association with high-transverse-momentum jets ($p_{\mathrm{T}} \geq 100$ GeV) and decaying into a charged-lepton pair ($e^+e^-,\mu^+\mu^-$) are presented. The measurements are performed using proton-proton collisions at $\sqrt{s}=13$ TeV corresponding to an integrated luminosity of $139$ fb$^{-1}$ collected by the ATLAS experiment at the LHC. Measurements of angular correlations between the $Z$ boson and the closest jet are performed in events with at least one jet with $p_{\mathrm{T}} \geq 500$ GeV. Event topologies of particular interest are the collinear emission of a $Z$ boson in dijet events and a boosted $Z$ boson recoiling against a jet. Fiducial cross sections are compared with state-of-the-art theoretical predictions. The data are found to agree with next-to-next-to-leading-order predictions by NNLOjet and with the next-to-leading-order multi-leg generators MadGraph5_aMC@NLO and Sherpa.
Measured fiducial differential cross sections for the Z boson p$_{\mathrm{T}}$ in Z($\to \ell^{+} \ell^{-}$) + high p$_{\mathrm{T}}$ jets events. The statistical, systematic, and luminosity uncertainties are given.
Measured fiducial differential cross sections for the leading jet p$_{\mathrm{T}}$ in Z($\to \ell^{+} \ell^{-}$) + high p$_{\mathrm{T}}$ jets events. The statistical, systematic, and luminosity uncertainties are given.
Measured fiducial differential cross sections for the jet multiplicity in Z($\to \ell^{+} \ell^{-}$) + high p$_{\mathrm{T}}$ jets events. The statistical, systematic, and luminosity uncertainties are given.
The charmonium χ states are observed in both π− and p Be interactions near 200 GeV/c via their radiative decay into J/ψ. The χ(3510) and χ(3555) are produced with roughly equal cross sections in π− collisions while the χ(3555) dominates in p collisions. Simple gluon fusion can account for χ production with incident protons but additional mechanisms are needed for incident π−.
No description provided.
A comparison of K±p and p±p elastic scattering is made for incident energy 50 to 175 GeV. Average values of 0.19±0.04 and 0.11±0.02 GeV2 were found for the invariant-momentum-transfer values of the Kp and pp crossover points, respectively.
KP AND PP CROSSOVER POINTS AT -T = 0.19 +- 0.04 AND 0.11 +- 0.02 GEV**2 (AVERAGE VALUES) RESPECTIVELY.
The Split Field Magnet facility at the CERN ISR has been used to measure inclusive resonance production in inelastic p-p collisions at a c.m. energy of 53 GeV. The mass spectrum of pairs of oppositely charged hadrons shows a strong correlation, which can be explained as a consequence of dominant vector meson production, accounting for more than 60% of all pions and kaons produced.
No description provided.
No description provided.
No description provided.
The inclusive cross sections for η production by the interactions of 280 GeV/c momentum π−, π+, and proton beams in hydrogen have been measured. The kinematical range covered is −0.45<xF<0.45, and 4.0<PT<7.0 GeV/c for FeynmanxF and transverse momentum respectively. The η to π0 cross section ratios are given for the three reactions. The ratio of π−p to π+p cross sections for η production in the above kinematic ranges is 1.22±0.08±0.11.
No description provided.
No description provided.
No description provided.