The dynamics of isolated-photon plus two-jet production in $pp$ collisions at a centre-of-mass energy of 13 TeV are studied with the ATLAS detector at the LHC using a dataset corresponding to an integrated luminosity of 36.1 fb$^{-1}$. Cross sections are measured as functions of a variety of observables, including angular correlations and invariant masses of the objects in the final state, $\gamma+jet+jet$. Measurements are also performed in phase-space regions enriched in each of the two underlying physical mechanisms, namely direct and fragmentation processes. The measurements cover the range of photon (jet) transverse momenta from 150 GeV (100 GeV) to 2 TeV. The tree-level plus parton-shower predictions from SHERPA and PYTHIA as well as the next-to-leading-order QCD predictions from SHERPA are compared with the measurements. The next-to-leading-order QCD predictions describe the data adequately in shape and normalisation except for regions of phase space such as those with high values of the invariant mass or rapidity separation of the two jets, where the predictions overestimate the data.
Measured cross sections for isolated-photon plus two-jet production as functions of $E_{\mathrm{T}}^{\gamma}$ for the total phase-space. The predictions from Sherpa NLO are also included.
Measured cross sections for isolated-photon plus two-jet production as functions of $p_{\mathrm{T}}^{\textrm{jet}}$ for the total phase-space. The predictions from Sherpa NLO are also included.
Measured cross sections for isolated-photon plus two-jet production as functions of $|y^{\textrm{jet}}|$ for the total phase-space. The predictions from Sherpa NLO are also included.
Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, $H\rightarrow\gamma\gamma$, $H\rightarrow ZZ^{*}\rightarrow 4 \ell$ and $H\rightarrow W W \rightarrow \ell\nu\ell\nu$. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of 7 TeV and 8 TeV, corresponding to an integrated luminosity of about 25 fb$^{-1}$. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson.
-2 log Likelihood in the $(\mu^f_{{\mathrm{{ggF}}+ttH}}, \mu^f_{{\mathrm{{VBF}}+VH}})$ plane for the $f=H\to \gamma\gamma$ channel and a Higgs boson mass $m_H = 125.5$ GeV. The original plain-text and ROOT files from <a href="https://doi.org/10.7484/inspirehep.data.a78c.hk44">10.7484/inspirehep.data.a78c.hk44</a> are accessible by clicking "Resources".
-2 log Likelihood in the $(\mu^f_{{\mathrm{{ggF}}+ttH}}, \mu^f_{{\mathrm{{VBF}}+VH}})$ plane for the $f=H\to ZZ^*\to 4\ell$ channel and a Higgs boson mass $m_H = 125.5$ GeV. The sharp lower edge is due to the small number of events in this channel and the requirement of a positive pdf. The original plain-text and ROOT files from <a href="https://doi.org/10.7484/inspirehep.data.rf5p.6m3k">10.7484/inspirehep.data.rf5p.6m3k</a> are accessible by clicking "Resources".
-2 log Likelihood in the $(\mu^f_{{\mathrm{{ggF}}+ttH}}, \mu^f_{{\mathrm{{VBF}}+VH}})$ plane for the $f=H\to WW^*\to\ell\nu\ell\nu$ channel and a Higgs boson mass $m_H = 125.5$ GeV. The original plain-text and ROOT files from <a href="https://doi.org/10.7484/inspirehep.data.26b4.ty5f">10.7484/inspirehep.data.26b4.ty5f</a> are accessible by clicking "Resources".
A search for long-lived particles decaying into hadrons and at least one muon is presented. The analysis selects events that pass a muon or missing-transverse-momentum trigger and contain a displaced muon track and a displaced vertex. The analyzed dataset of proton-proton collisions at $\sqrt{s} = 13$ TeV was collected with the ATLAS detector and corresponds to 136 fb$^{-1}$. The search employs dedicated reconstruction techniques that significantly increase the sensitivity to long-lived particle decays that occur in the ATLAS inner detector. Background estimates for Standard Model processes and instrumental effects are extracted from data. The observed event yields are compatible with those expected from background processes. The results are presented as limits at 95% confidence level on model-independent cross sections for processes beyond the Standard Model, and interpreted as exclusion limits in scenarios with pair-production of long-lived top squarks that decay via a small $R$-parity-violating coupling into a quark and a muon. Top squarks with masses up to 1.7 TeV are excluded for a lifetime of 0.1 ns, and masses below 1.3 TeV are excluded for lifetimes between 0.01 ns and 30 ns.
Vertex selection acceptance for the $\tilde{t}$ $R$-hadron benchmark model as a function of the transverse decay distance $r_{DV}$.
Vertex selection acceptance for the $\tilde{t}$ $R$-hadron benchmark model as a function of the transverse decay distance $r_{DV}$.
Vertex selection efficiency for the $\tilde{t}$ $R$-hadron benchmark model as a function of the transverse decay distance $r_{DV}$.
Bose-Einstein correlations of charged hadrons are measured over a broad multiplicity range, from a few particles up to about 250 reconstructed charged hadrons in proton-proton collisions at $\sqrt{s} =$ 13 TeV. The results are based on data collected using the CMS detector at the LHC during runs with a special low-pileup configuration. Three analysis techniques with different degrees of dependence on simulations are used to remove the non-Bose-Einstein background from the correlation functions. All three methods give consistent results. The measured lengths of homogeneity are studied as functions of particle multiplicity as well as average pair transverse momentum and mass. The results are compared with data from both CMS and ATLAS at $\sqrt{s} =$ 7 TeV, as well as with theoretical predictions.
The Rinv fit parameters as a function of particle-level multiplicities using the HCS method in pp collisions at 13 TeV.
The Rinv fit parameters as a function of particle-level multiplicities (for p_T^trk>0.1GeV) using the HCS method in pp collisions at 13 TeV.
The Rinv fit parameters as a function of kT using the HCS method in pp collisions at 13 TeV.
A search for a heavy Higgs boson H decaying into the observed Higgs boson h with a mass of 125 GeV and another Higgs boson h$_\mathrm{S}$ is presented. The h and h$_\mathrm{S}$ bosons are required to decay into a pair of tau leptons and a pair of b quarks, respectively. The search uses a sample of proton-proton collisions collected with the CMS detector at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 137 fb$^{-1}$. Mass ranges of 240-3000 GeV for $m_\mathrm{H}$ and 60-2800 GeV for $m_\mathrm{h_S}$ are explored in the search. No signal has been observed. Model independent 95% confidence level upper limits on the product of the production cross section and the branching fractions of the signal process are set with a sensitivity ranging from 125 fb (for $m_\mathrm{H}$ $=$ 240 GeV) to 2.7 fb (for $m_\mathrm{H}$ $=$ 1000 GeV). These limits are compared to maximally allowed products of the production cross section and the branching fractions of the signal process in the next-to-minimal supersymmetric extension of the standard model.
Expected and observed exclusion limits for heavy higgs boson mass 240 GeV
Expected and observed exclusion limits for heavy higgs boson mass 280 GeV
Expected and observed exclusion limits for heavy higgs boson mass 320 GeV
Deuteron production in high-energy collisions is sensitive to the space-time evolution of the collision system, and is typically described by a coalescence mechanism. For the first time, we present results on jet-associated deuteron production in \pp collisions at $\sqrt{s}=13$ TeV, providing an opportunity to test the established picture for deuteron production in events with a hard scattering. Using a trigger particle with high transverse-momentum ($p_{\rm T}>5$ GeV/$c$) as a proxy for the presence of a jet at midrapidity, we observe a measurable population of deuterons being produced around the jet proxy. The associated deuteron yield measured in a narrow angular range around the trigger particle differs by 2.4-4.8 standard deviations from the uncorrelated background. The data are described by PYTHIA model calculations featuring baryon coalescence.
The per-trigger associated yield versus $\Delta\varphi$ for charged particles with $p_{\rm T}>5.0$ GeV/$c$ and associate deuterons and anti-deuterons for 1.0-1.35 GeV/$c$.
The per-trigger associated yield versus $\Delta\varphi$ for charged particles with $p_{\rm T}>5.0$ GeV/$c$ and associate deuterons and anti-deuterons for 1.35-1.8 GeV/$c$.
The per-trigger associated yield versus $\Delta\varphi$ for charged particles with $p_{\rm T}>5.0$ GeV/$c$ and associate deuterons and anti-deuterons for 1.8-2.4 GeV/$c$.
The first measurements of the production of muons and electrons from heavy-flavour hadron decays in Xe-Xe collisions at $\sqrt{s_{\rm NN}}$ = 5.44 TeV, using the ALICE detector at the LHC, are reported. The measurement of the nuclear modification factor $R_{\rm AA}$ is performed as a function of transverse momentum $p_{\rm T}$ in several centrality classes at forward rapidity ($2.5 < y <4$) and midrapidity ($\vert y \vert < 0.8$) for muons and electrons from heavy-flavour hadron decays, respectively. A suppression by a factor up to about 2.5 compared to the binary-scaled pp reference is observed in central collisions at both central and forward rapidities. The $R_{\rm AA}$ of muons from heavy-flavour hadron decays is compared to previous measurements in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV. When the nuclear modification factors are compared in the centrality classes 0-10% for Xe-Xe collisions and 10-20% for Pb-Pb collisions, which have similar charged-particle multiplicity density, a similar suppression, with $R_{\rm AA} \sim 0.4$ in the $p_{\rm T}$ interval $4 < p_{\rm T} < 8$ GeV/$c$, is observed. The comparison of the measured $R_{\rm AA}$ values in the two collision systems brings new insights on the properties of the quark-gluon plasma by investigating the system-size and path-length dependence of medium-induced parton energy loss. The results of muons and electrons from heavy-flavour hadron decays provide new constraints to model calculations.
Transverse momentum differential production of muons from heavy-flavour hadron decays at forward rapidity in Xe-Xe collisions at 5.44 TeV.
Transverse momentum differential production of muons from heavy-flavour hadron decays at forward rapidity in Xe-Xe collisions at 5.44 TeV.
Transverse momentum differential production of muons from heavy-flavour hadron decays at forward rapidity in Xe-Xe collisions at 5.44 TeV.
Two-particle angular correlations are measured in high-multiplicity proton-proton collisions at $\sqrt{s} =13$ TeV by the ALICE Collaboration. The yields of particle pairs at short-($\Delta\eta$$\sim$ 0) and long-range ($1.6 < |\Delta\eta| < 1.8$) in pseudorapidity are extracted on the near-side ($\Delta\varphi$$\sim$ 0). They are reported as a function of transverse momentum ($p_{\mathrm T}$) in the range $1 <p_{\mathrm T}< 4$ GeV/$c$. Furthermore, the event-scale dependence is studied for the first time by requiring the presence of high-$p_{\rm T}$ leading particles and jets for varying $p_{\rm T}$ thresholds. The results demonstrate that the long-range "ridge" yield, possibly related to the collective behavior of the system, is present in events with high-$p_{\mathrm T}$ processes. The magnitudes of the short- and long-range yields are found to grow with the event scale. The results are compared to EPOS LHC and PYTHIA 8 calculations, with and without string-shoving interactions. It is found that while both models describe the qualitative trends in the data, calculations from EPOS LHC show a better quantitative agreement, in particular for the $p_{\rm T}$ and event-scale dependencies.
Long-range $\Delta\varphi$ projections in minimum bias and high-multiplicity events for various $p_\mathrm{T,trig(assoc)}$ ranges.
Ridge yield as a function of $p_\mathrm{T,trig(assoc)}$ in high-multiplicity events.
Long-range $\Delta\varphi$ projections in high-multiplicity events with event-scale selections, requiring minimum $p_\mathrm{T,jet}$
This article presents measurements of the $t$-channel single top-quark ($t$) and top-antiquark ($\bar{t}$) total production cross sections $\sigma(tq)$ and $\sigma(\bar{t}q)$, their ratio $R_{t}=\sigma(tq)/\sigma(\bar{t}q)$, and a measurement of the inclusive production cross section $\sigma(tq + \bar{t}q)$ in proton--proton collisions at $\sqrt{s} = 7$ TeV at the LHC. Differential cross sections for the $tq$ and $\bar{t}q$ processes are measured as a function of the transverse momentum and the absolute value of the rapidity of $t$ and $\bar{t}$, respectively. The analyzed data set was recorded with the ATLAS detector and corresponds to an integrated luminosity of 4.59 fb$^{-1}$. Selected events contain one charged lepton, large missing transverse momentum, and two or three jets. The cross sections are measured by performing a binned maximum-likelihood fit to the output distributions of neural networks. The resulting measurements are $\sigma(tq)= 46\pm 6\; \mathrm{pb}$, $\sigma(\bar{t}q)= 23 \pm 4\; \mathrm{pb}$, $R_{t}=2.04\pm 0.18$, and $\sigma(tq + \bar{t}q)= 68 \pm 8\; \mathrm{pb}$, consistent with the Standard Model expectation. The uncertainty on the measured cross sections is dominated by systematic uncertainties, while the uncertainty on $R_{t}$ is mainly statistical. Using the ratio of $\sigma(tq + \bar{t}q)$ to its theoretical prediction, and assuming that the top-quark-related CKM matrix elements obey the relation $|V_{tb}|\gg |V_{ts}|, |V_{td}|$, we determine $|V_{tb}|=1.02 \pm 0.07$.
Differential t-channel top-quark production cross sections and normalized differential t-channel top-quark production cross sections as functions of PT(TOP).
Predicted and observed events yields for the 2-jet and 3-jet channels considered in this measurement. The multijet background is estimated using data-driven techniques (see Sec. VB); an uncertainty of $50\%$ is applied. All the other expectations are derived using theoretical cross sections and their uncertainties (see Secs. VA and VC in the paper).
Differential t-channel top-quark production cross sections and normalized differential t-channel top-quark production cross sections as functions of PT(TOPBAR).
The first measurements of the scattering parameters of $\Lambda$K pairs in all three charge combinations ($\Lambda$K$^{+}$, $\Lambda$K$^{-}$, and $\Lambda\mathrm{K^{0}_{S}}$) are presented. The results are achieved through a femtoscopic analysis of $\Lambda$K correlations in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV recorded by ALICE at the LHC. The femtoscopic correlations result from strong final-state interactions, and are fit with a parametrization allowing for both the characterization of the pair emission source and the measurement of the scattering parameters for the particle pairs. Extensive studies with the THERMINATOR 2 event generator provide a good description of the non-femtoscopic background, which results mainly from collective effects, with unprecedented precision. Furthermore, together with HIJING simulations, this model is used to account for contributions from residual correlations induced by feed-down from particle decays. The extracted scattering parameters indicate that the strong force is repulsive in the $\Lambda\rm{K}^{+}$ interaction and attractive in the $\Lambda\rm{K}^{-}$ interaction. The data hint that the and $\Lambda\rm{K}^{0}_{S}$ interaction is attractive, however the uncertainty of the result does not permit such a decisive conclusion. The results suggest an effect arising either from different quark-antiquark interactions between the pairs ($\rm s\overline{s}$ in $\Lambda$K$^{+}$ and $\rm u\overline{u}$ in $\Lambda$K$^{-}$) or from different net strangeness for each system (S = 0 for $\Lambda$K$^{+}$, and S = $-2$ for $\Lambda$K$^{-}$). Finally, the $\Lambda$K systems exhibit source radii larger than expected from extrapolation from identical particle femtoscopic studies. This effect is interpreted as resulting from the separation in space-time of the single-particle $\Lambda$ and K source distributions.
Invariant mass distributions in the 0--10\% centrality interval of (a) p$\uppi^{-}$ pairs showing the $\Lambda$ peak for V$^{0}$ candidates.
Invariant mass distributions in the 0--10\% centrality interval of $\uppi^{+}\uppi^{-}$ pairs showing the $\mathrm{K^{0}_{S}}$ peak for V$^{0}$ candidates.
Measured correlation function for the $\Lambda\mathrm{K^{+}}\oplus\overline{\Lambda}\mathrm{K^{-}}$ system in the 0--10\% centrality interval.
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