First Dark Matter Search Results from the LUX-ZEPLIN (LZ) Experiment

The LZ collaboration Aalbers, J. ; Akerib, D.S. ; Akerlof, C.W. ; et al.
Phys.Rev.Lett. 131 (2023) 041002, 2023.
Inspire Record 2107834 DOI 10.17182/hepdata.144760

The LUX-ZEPLIN experiment is a dark matter detector centered on a dual-phase xenon time projection chamber operating at the Sanford Underground Research Facility in Lead, South Dakota, USA. This Letter reports results from LUX-ZEPLIN's first search for weakly interacting massive particles (WIMPs) with an exposure of 60~live days using a fiducial mass of 5.5 t. A profile-likelihood ratio analysis shows the data to be consistent with a background-only hypothesis, setting new limits on spin-independent WIMP-nucleon, spin-dependent WIMP-neutron, and spin-dependent WIMP-proton cross sections for WIMP masses above 9 GeV/c$^2$. The most stringent limit is set for spin-independent scattering at 36 GeV/c$^2$, rejecting cross sections above 9.2$\times 10^{-48}$ cm$^2$ at the 90% confidence level.

5 data tables

90% CL WIMP SI cross sections, including sensitivities

90% CL WIMP SDn cross sections, including sensitivities and nuclear structure uncertainties

90% CL WIMP SDp cross sections, including sensitivities and nuclear structure uncertainties

More…

Observation of electroweak production of a same-sign $W$ boson pair in association with two jets in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Phys.Rev.Lett. 123 (2019) 161801, 2019.
Inspire Record 1738841 DOI 10.17182/hepdata.84643

This Letter presents the observation and measurement of electroweak production of a same-sign $W$ boson pair in association with two jets using 36.1 fb$^{-1}$ of proton-proton collision data recorded at a center-of-mass energy of $\sqrt{s}=13$ TeV by the ATLAS detector at the Large Hadron Collider. The analysis is performed in the detector fiducial phase-space region, defined by the presence of two same-sign leptons, electron or muon, and at least two jets with a large invariant mass and rapidity difference. A total of 122 candidate events are observed for a background expectation of $69 \pm 7$ events, corresponding to an observed signal significance of 6.5 standard deviations. The measured fiducial signal cross section is $\sigma^{\mathrm {fid.}}=2.89^{+0.51}_{-0.48} \mathrm{(stat.)} ^{+0.29}_{-0.28} \mathrm{(syst.)}$ fb.

6 data tables

Measured fiducial cross section.

The $m_{jj}$ distribution for events meeting all selection criteria for the signal region. Signal and individual background distributions are shown as predicted after the fit. The last bin includes the overflow. The highest value measured in a candidate event in data is $m_{jj}=3.8$ TeV.

The $m_{ll}$ distribution for events meeting all selection criteria for the signal region as predicted after the fit. The fitted signal strength and nuisance parameters have been propagated, with the exception of the uncertainties due to the interference and electroweak corrections for which a flat uncertainty is assigned. The last bin includes the overflow. The highest value measured in a candidate event in data is $m_{ll}=824$ GeV.

More…

Search for excited electrons singly produced in proton-proton collisions at $\sqrt{s} = 13$ TeV with the ATLAS experiment at the LHC

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Eur.Phys.J.C 79 (2019) 803, 2019.
Inspire Record 1738845 DOI 10.17182/hepdata.90452

A search for excited electrons produced in $pp$ collisions at $\sqrt{s} = 13$ TeV via a contact interaction $q\bar{q} \to ee^*$ is presented. The search uses 36.1 fb$^{-1}$ of data collected in 2015 and 2016 by the ATLAS experiment at the Large Hadron Collider. Decays of the excited electron via a contact interaction into an electron and a pair of quarks ($eq\bar{q}$) are targeted in final states with two electrons and two hadronic jets, and decays via a gauge interaction into a neutrino and a $W$ boson ($\nu W$) are probed in final states with an electron, missing transverse momentum, and a large-radius jet consistent with a hadronically decaying $W$ boson. No significant excess is observed over the expected backgrounds. Upper limits are calculated for the $pp \to ee^* \to eeq\bar{q}$ and $pp \to ee^* \to e\nu W$ production cross sections as a function of the excited electron mass $m_{e^*}$ at 95% confidence level. The limits are translated into lower bounds on the compositeness scale parameter $\Lambda$ of the model as a function of $m_{e^*}$. For $m_{e^*} < 0.5$ TeV, the lower bound for $\Lambda$ is 11 TeV. In the special case of $m_{e^*} = \Lambda$, the values of $m_{e^*} < 4.8$ TeV are excluded. The presented limits on $\Lambda$ are more stringent than those obtained in previous searches.

7 data tables

The distribution of $m_{lljj}$ used to discriminate the signal from background processes in the $eejj$ channel. The distribution is shown after applying the preselection criteria. The background contributions are constrained using the CRs. The signal models assume $\Lambda$ = 5 TeV. The uncertainties for the expected backgrounds represent all considered systematic and statistical sources.

The distribution of $m_{T}^{\nu W}$ used to discriminate the signal and background processes in the $e\nu J$ channel. The distribution is shown after applying the preselection criteria. The background contributions are constrained using the CRs. The signal models assume $\Lambda$ = 5 TeV. The last bin includes overflow events (the underflow is not shown). The uncertainties for the expected backgrounds represent all considered systematic and statistical sources.

Upper limits on $\sigma\times B$ as a function of $m_{e^*}$ in the $eejj$ channel. The $\pm 1(2)\sigma$ uncertainty bands around the expected limit represent all sources of systematic and statistical uncertainties.

More…

Measurement of fiducial and differential $W^+W^-$ production cross-sections at $\sqrt{s}=$13 TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Eur.Phys.J.C 79 (2019) 884, 2019.
Inspire Record 1734263 DOI 10.17182/hepdata.89225

A measurement of fiducial and differential cross-sections for $W^+W^-$ production in proton-proton collisions at $\sqrt{s}=$13 TeV with the ATLAS experiment at the Large Hadron Collider using data corresponding to an integrated luminosity of $36.1$ fb$^{-1}$ is presented. Events with one electron and one muon are selected, corresponding to the decay of the diboson system as $WW\rightarrow e^{\pm}\nu\mu^{\mp}\nu$. To suppress top-quark background, events containing jets with a transverse momentum exceeding 35 GeV are not included in the measurement phase space. The fiducial cross-section, six differential distributions and the cross-section as a function of the jet-veto transverse momentum threshold are measured and compared with several theoretical predictions. Constraints on anomalous electroweak gauge boson self-interactions are also presented in the framework of a dimension-six effective field theory.

43 data tables

Measured fiducial cross-section as a function of the jet-veto $p_{T}$ threshold. The value at the jet-veto $p_{T}$ threshold of 35GeV corresponds to the nominal fiducial cross section measured in this publication.

Statistical correlation between bins in data for the measured fiducial cross-section as a function of the jet-veto $p_{T}$ threshold. The value at the jet-veto $p_{T}$ threshold of 35GeV corresponds to the nominal fiducial cross section measured in this publication.

Total correlation between bins in data for the measured fiducial cross-section as a function of the jet-veto $p_{T}$ threshold. The value at the jet-veto $p_{T}$ threshold of 35GeV corresponds to the nominal fiducial cross section measured in this publication.

More…

Search for a right-handed gauge boson decaying into a high-momentum heavy neutrino and a charged lepton in $pp$ collisions with the ATLAS detector at $\sqrt{s}=13$ TeV

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Phys.Lett.B 798 (2019) 134942, 2019.
Inspire Record 1731814 DOI 10.17182/hepdata.89455

A search for a right-handed gauge boson $W_{\mathrm{R}}$, decaying into a boosted right-handed heavy neutrino $N_{\mathrm{R}}$, in the framework of Left-Right Symmetric Models is presented. It is based on data from proton-proton collisions with a centre-of-mass energy of 13 TeV collected by the ATLAS detector at the Large Hadron Collider during the years 2015, 2016 and 2017, corresponding to an integrated luminosity of 80 fb$^{-1}$. The search is performed separately for electrons and muons in the final state. A distinguishing feature of the search is the use of large-radius jets containing electrons. Selections based on the signal topology result in smaller background compared with to expected signal. No significant deviation from the Standard Model prediction is observed and lower limits are set in the $W_{\mathrm{R}}$ and $N_{\mathrm{R}}$ mass plane. Mass values of the $W_{\mathrm{R}}$ smaller than 3.8-5 TeV are excluded for $N_{\mathrm{R}}$ in the mass range 0.1-1.8 TeV.

4 data tables

Expected 95% CL exclusion contours in the $(m_{N_R}, m_{W_R})$ plane in the electron channel.

Observed 95% CL exclusion contours in the $(m_{N_R}, m_{W_R})$ plane in the electron channel.

Expected 95% CL exclusion contours in the $(m_{N_R}, m_{W_R})$ plane in the muon channel.

More…

Fluctuations of anisotropic flow in Pb+Pb collisions at $ \sqrt{{\mathrm{s}}_{\mathrm{NN}}} $ = 5.02 TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
JHEP 01 (2020) 051, 2020.
Inspire Record 1728935 DOI 10.17182/hepdata.89325

Multi-particle azimuthal cumulants are measured as a function of centrality and transverse momentum using 470 $\mu$b$^{-1}$ of Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV with the ATLAS detector at the LHC. These cumulants provide information on the event-by-event fluctuations of harmonic flow coefficients $v_n$ and correlated fluctuations between two harmonics $v_n$ and $v_m$. For the first time, a non-zero four-particle cumulant is observed for dipolar flow, $v_1$. The four-particle cumulants for elliptic flow, $v_2$, and triangular flow, $v_3$, exhibit a strong centrality dependence and change sign in ultra-central collisions. This sign change is consistent with significant non-Gaussian fluctuations in $v_2$ and $v_3$. The four-particle cumulant for quadrangular flow, $v_4$, is found to change sign in mid-central collisions. Correlations between two harmonics are studied with three- and four-particle mixed-harmonic cumulants, which indicate an anti-correlation between $v_2$ and $v_3$, and a positive correlation between $v_2$ and $v_4$. These correlations decrease in strength towards central collisions and either approach zero or change sign in ultra-central collisions. To investigate the possible flow fluctuations arising from intrinsic centrality or volume fluctuations, the results are compared between two different event classes used for centrality definitions. In peripheral and mid-central collisions where the cumulant signals are large, only small differences are observed. In ultra-central collisions, the differences are much larger and transverse momentum dependent. These results provide new information to disentangle flow fluctuations from the initial and final states, as well as new insights on the influence of centrality fluctuations.

291 data tables

NchRec v.s. Et

<NchRec> w.r.t. Et

<Et> w.r.t. NchRec

More…

Measurement of jet-substructure observables in top quark, $W$ boson and light jet production in proton-proton collisions at $\sqrt{s}=13$ TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
JHEP 08 (2019) 033, 2019.
Inspire Record 1724098 DOI 10.17182/hepdata.89324

A measurement of jet substructure variables is presented using data collected in 2016 by the ATLAS experiment at the LHC with proton-proton collisions at $\sqrt{s}=13$ TeV. Large-radius jets groomed with the trimming and soft-drop algorithms are studied. Dedicated event selections are used to study jets produced by light quarks or gluons, and hadronically decaying top quarks and $W$ bosons. The variables measured are sensitive to pronged substructure, and therefore are typically used for tagging jets from boosted massive particles. These include the energy correlation functions and the $N$-subjettiness variables. The number of subjets and the Les Houches angularity are also considered. The distributions of the substructure variables, corrected for detector effects, are compared to the predictions of various Monte Carlo event generators. They are also compared between the large-radius jets originating from light quarks or gluons, and hadronically decaying top quarks and $W$ bosons.

88 data tables

Figure 3a, Normalised differential Nsubjets distribution for soft-drop groomed jets, Dijet selection.

Figure 4a, Normalised differential LHA distribution for soft-drop groomed jets, Dijet selection

Figure 5a, Normalised differential C2 distribution for soft-drop groomed jets, Dijet selection

More…

Measurement of prompt photon production in $\sqrt{s_\mathrm{NN}} = 8.16$ TeV $p$+Pb collisions with ATLAS

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Phys.Lett.B 796 (2019) 230-252, 2019.
Inspire Record 1723858 DOI 10.17182/hepdata.87256

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.

7 data tables

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).

More…

Search for heavy particles decaying into a top-quark pair in the fully hadronic final state in $pp$ collisions at $\sqrt{s} =13$ TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Phys.Rev.D 99 (2019) 092004, 2019.
Inspire Record 1722036 DOI 10.17182/hepdata.89050

A search for new particles decaying into a pair of top quarks is performed using proton-proton collision data recorded with the ATLAS detector at the Large Hadron Collider at a center-of-mass energy of $\sqrt{s} = $13 TeV corresponding to an integrated luminosity of 36.1 fb$^{-1}$. Events consistent with top-quark pair production and the fully hadronic decay mode of the top quarks are selected by requiring multiple high transverse momentum jets including those containing $b$-hadrons. Two analysis techniques, exploiting dedicated top-quark pair reconstruction in different kinematic regimes, are used to optimize the search sensitivity to new hypothetical particles over a wide mass range. The invariant mass distribution of the two reconstructed top-quark candidates is examined for resonant production of new particles with various spins and decay widths. No significant deviation from the Standard Model prediction is observed and limits are set on the production cross-section times branching fraction for new hypothetical $Z'$ bosons, dark-matter mediators, Kaluza-Klein gravitons and Kaluza-Klein gluons. By comparing with the predicted production cross-sections, the $Z'$ boson in the topcolor-assisted-technicolor model is excluded for masses up to 3.1$-$3.6 TeV, the dark-matter mediators in a simplified framework are excluded in the mass ranges from 0.8 TeV to 0.9 TeV and from 2.0 TeV to 2.2 TeV, and the Kaluza-Klein gluon is excluded for masses up to 3.4 TeV, depending on the decay widths of the particles.

25 data tables

Acceptance times selection efficiency for topcolor-assisted-technicolor Z$^{\prime}_{TC2}$ as a function of top-quark pair mass for all regions A–D in the resolved analysis and the combination of all SRs in the boosted analysis.

Acceptance times selection efficiency for Kaluza-Klein graviton as a function of top-quark pair mass for all regions A–D in the resolved analysis and the combination of all SRs in the boosted analysis.

Acceptance times selection efficiency for Kaluza-Klein gluon Γ=30% as a function of top-quark pair mass for all regions A–D in the resolved analysis and the combination of all SRs in the boosted analysis.

More…

Measurement of $W^{\pm}Z$ production cross sections and gauge boson polarisation in $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Eur.Phys.J.C 79 (2019) 535, 2019.
Inspire Record 1720438 DOI 10.17182/hepdata.83701

This paper presents measurements of $W^{\pm}Z$ production cross sections in $pp$ collisions at a centre-of-mass energy of 13 TeV. The data were collected in 2015 and 2016 by the ATLAS experiment at the Large Hadron Collider, and correspond to an integrated luminosity of 36.1 fb$^{-1}$. The $W^{\pm}Z$ candidate events are reconstructed using leptonic decay modes of the gauge bosons into electrons and muons. The measured inclusive cross section in the detector fiducial region for a single leptonic decay mode is $\sigma_{W^\pm Z \rightarrow \ell^{'} \nu \ell \ell}^{\textrm{fid.}} = 63.7 \pm 1.0$ (stat.) $\pm 2.3$ (syst.) $\pm 1.4$ (lumi.) fb, reproduced by the next-to-next-to-leading-order Standard Model prediction of $61.5^{+1.4}_{-1.3}$ fb. Cross sections for $W^+Z$ and $W^-Z$ production and their ratio are presented as well as differential cross sections for several kinematic observables. An analysis of angular distributions of leptons from decays of $W$ and $Z$ bosons is performed for the first time in pair-produced events in hadronic collisions, and integrated helicity fractions in the detector fiducial region are measured for the $W$ and $Z$ bosons separately. Of particular interest, the longitudinal helicity fraction of pair-produced vector bosons is also measured.

24 data tables

The measured $W^{\pm}Z$ fiducial cross section in the four channels and their combination. The first systematic uncertainty is the combined systematic uncertainty excluding luminosity uncertainty, the second is the modelling uncertainty, the third is luminosity uncertainty.

The measured $W^{+}Z$ fiducial cross section in the four channels and their combination. The first systematic uncertainty is the combined systematic uncertainty excluding luminosity uncertainty, the second is the modelling uncertainty, the third is luminosity uncertainty.

The measured $W^{-}Z$ fiducial cross section in the four channels and their combination. The first systematic uncertainty is the combined systematic uncertainty excluding luminosity uncertainty, the second is the modelling uncertainty, the third is luminosity uncertainty.

More…

Measurement of the four-lepton invariant mass spectrum in 13 TeV proton-proton collisions with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
JHEP 04 (2019) 048, 2019.
Inspire Record 1720442 DOI 10.17182/hepdata.84818

A measurement of the four-lepton invariant mass spectrum is made with the ATLAS detector, using an integrated luminosity of 36.1 fb$^{-1}$ of proton-proton collisions at $\sqrt{s}$ = 13 TeV delivered by the Large Hadron Collider. The differential cross-section is measured for events containing two same-flavour opposite-sign lepton pairs. It exhibits a rich structure, with different mass regions dominated in the Standard Model by single $Z$ boson production, Higgs boson production, and $Z$ boson pair production, and non-negligible interference effects at high invariant masses. The measurement is compared with state-of-the-art Standard Model calculations, which are found to be consistent with the data. These calculations are used to interpret the data in terms of $gg\rightarrow ZZ \rightarrow 4\ell$ and $Z \rightarrow 4\ell$ subprocesses, and to place constraints on a possible contribution from physics beyond the Standard Model.

29 data tables

Measured and expected differential cross-section $\text{d}\sigma / \text{d} m_{4l}$ as a function of $m_{4l}$

Measured and expected differential cross-section $\text{d}\sigma / \text{d} m_{4l}$ as a function of $m_{4l}$ in bin of 0$< p_{T}^{4l} <$20 GeV

Measured and expected differential cross-section $\text{d}\sigma / \text{d} m_{4l}$ as a function of $m_{4l}$ in bin of 20$< p_{T}^{4l} <$50 GeV

More…

Search for long-lived neutral particles in $pp$ collisions at $\sqrt{s}$ = 13 TeV that decay into displaced hadronic jets in the ATLAS calorimeter

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Eur.Phys.J.C 79 (2019) 481, 2019.
Inspire Record 1719200 DOI 10.17182/hepdata.86552

This paper describes a search for pairs of neutral, long-lived particles decaying in the ATLAS calorimeter. Long-lived particles occur in many extensions to the Standard Model and may elude searches for new promptly decaying particles. The analysis considers neutral, long-lived scalars with masses between 5 GeV and 400 GeV, produced from decays of heavy bosons with masses between 125 GeV and 1000 GeV, where the long-lived scalars decay into Standard Model fermions. The analysis uses either 10.8 fb$^{-1}$ or 33.0 fb$^{-1}$ of data (depending on the trigger) recorded in 2016 at the LHC with the ATLAS detector in proton-proton collisions at a centre-of-mass energy of 13 TeV. No significant excess is observed, and limits are reported on the production cross section times branching ratio as a function of the proper decay length of the long-lived particles.

39 data tables

Trigger efficiency of simulated signal events as a function of the LLP $p_T$ for a selection of signal samples.

Trigger efficiency of simulated signal events as a function of the LLP decay position in the $x-y$ plane for LLPs decaying in the HCal barrel for three signal samples.

Trigger efficiency of simulated signal events as a function of the LLP decay position in the $z$ direction for LLPs decaying in the HCal endcaps for three signal samples.

More…

Version 2
Search for heavy charged long-lived particles in the ATLAS detector in 31.6 fb$^{-1}$ of proton-proton collision data at $\sqrt{s} = 13$ TeV

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Phys.Rev.D 99 (2019) 092007, 2019.
Inspire Record 1718558 DOI 10.17182/hepdata.86565

A search for heavy charged long-lived particles is performed using a data sample of 36.1 fb$^{-1}$ of proton-proton collisions at $\sqrt{s} = 13$ TeV collected by the ATLAS experiment at the Large Hadron Collider. The search is based on observables related to ionization energy loss and time of flight, which are sensitive to the velocity of heavy charged particles traveling significantly slower than the speed of light. Multiple search strategies for a wide range of lifetimes, corresponding to path lengths of a few meters, are defined as model-independently as possible, by referencing several representative physics cases that yield long-lived particles within supersymmetric models, such as gluinos/squarks ($R$-hadrons), charginos and staus. No significant deviations from the expected Standard Model background are observed. Upper limits at 95% confidence level are provided on the production cross sections of long-lived $R$-hadrons as well as directly pair-produced staus and charginos. These results translate into lower limits on the masses of long-lived gluino, sbottom and stop $R$-hadrons, as well as staus and charginos of 2000 GeV, 1250 GeV, 1340 GeV, 430 GeV and 1090 GeV, respectively.

60 data tables

- - - - - - - - Overview of HEPData Record - - - - - - - - <br/><br/> <b>Lower mass requirement for signal regions.</b> <ul> <li><a href="86565?version=1&table=Table1">Gluinos and squarks</a></li> <li><a href="86565?version=1&table=Table2">Staus and charginos</a></li> </ul> <b>Discovery regions:</b> <ul> <li><a href="86565?version=1&table=Table3">Yields</a></li> <li><a href="86565?version=1&table=Table6">p0-values and limits</a></li> </ul> <b>Signal yield tables:</b> <ul> <li><a href="86565?version=1&table=Table4">MS-agnostic R-hadron search</a></li> <li><a href="86565?version=1&table=Table5">Full-detector R-hadron search</a></li> <li><a href="86565?version=1&table=Table7">MS-agnostic search for metastable gluino R-hadrons</a></li> <li><a href="86565?version=1&table=Table8">Full-detector direct-stau search</a></li> <li><a href="86565?version=1&table=Table9">Full-detector chargino search</a></li> </ul> <b>Limits:</b> <ul> <li><a href="86565?version=1&table=Table10">Gluino R-hadron search</a></li> <li><a href="86565?version=1&table=Table11">Sbottom R-hadron search</a></li> <li><a href="86565?version=1&table=Table12">Stop R-hadron search</a></li> <li><a href="86565?version=1&table=Table13">Stau search</a></li> <li><a href="86565?version=1&table=Table14">Chargino search</a></li> <li><a href="86565?version=1&table=Table15">Meta-stable gluino R-hadron search</a></li> <li><a href="86565?version=1&table=Table17">Meta-stable gluino R-hadron search</a></li> </ul> <b>Acceptance and efficiency:</b> <ul> <li><a href="86565?version=1&table=Table16">MS-agnostic R-hadron search</a></li> </ul> <b>Truth quantities:</b> <ul> <li><a href="86565?version=1&table=Table18">Flavor composition of 800 GeV stop R-hadrons simulated using the generic model</a></li> <li><a href="86565?version=1&table=Table19">Flavor composition of 800 GeV anti-stop R-hadrons simulated using the generic model</a></li> <li><a href="86565?version=1&table=Table20">Flavor composition of 800 GeV stop R-hadrons simulated using the Regge model</a></li> <li><a href="86565?version=1&table=Table21">Flavor composition of 800 GeV anti-stop R-hadrons simulated using the Regge model</a></li> </ul> <b>Reinterpretation material:</b> <ul> <li><a href="86565?version=1&table=Table22">ETmiss trigger efficiency as function of true ETmiss</a></li> <li><a href="86565?version=1&table=Table23">Single-muon trigger efficiency as function of |eta| and beta</a></li> <li><a href="86565?version=1&table=Table24">Candidate reconstruction efficiency for ID+Calo selection</a></li> <li><a href="86565?version=1&table=Table25">Candidate reconstruction efficiency for loose selection</a></li> <li><a href="86565?version=1&table=Table26">Efficiency for a loose candidate to be promoted to a tight candidate</a></li> <li><a href="86565?version=1&table=Table27">Resolution and average of reconstructed dE/dx mass for a given simulated mass for ID+calo candidates</a></li> <li><a href="86565?version=1&table=Table28">Resolution and average of reconstructed ToF mass for a given simulated mass for ID+calo candidates</a></li> <li><a href="86565?version=1&table=Table29">Resolution and average of reconstructed ToF mass for a given simulated mass for FullDet candidates</a></li> </ul> <p><b>Pseudo-code snippets</b> and <b>example SLHA setups</b> are available in the "Resources" linked on the left, and more detailed reinterpretation material is available at <a href="http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/SUSY-2016-32/hepdata_info.pdf">http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/SUSY-2016-32/hepdata_info.pdf</a>.</p>

- - - - - - - - Overview of HEPData Record - - - - - - - - <br/><br/> <b>Lower mass requirement for signal regions.</b> <ul> <li><a href="86565?version=1&table=Table1">Gluinos and squarks</a></li> <li><a href="86565?version=1&table=Table2">Staus and charginos</a></li> </ul> <b>Discovery regions:</b> <ul> <li><a href="86565?version=1&table=Table3">Yields</a></li> <li><a href="86565?version=1&table=Table6">p0-values and limits</a></li> </ul> <b>Signal yield tables:</b> <ul> <li><a href="86565?version=1&table=Table4">MS-agnostic R-hadron search</a></li> <li><a href="86565?version=1&table=Table5">Full-detector R-hadron search</a></li> <li><a href="86565?version=1&table=Table7">MS-agnostic search for metastable gluino R-hadrons</a></li> <li><a href="86565?version=1&table=Table8">Full-detector direct-stau search</a></li> <li><a href="86565?version=1&table=Table9">Full-detector chargino search</a></li> </ul> <b>Limits:</b> <ul> <li><a href="86565?version=1&table=Table10">Gluino R-hadron search</a></li> <li><a href="86565?version=1&table=Table11">Sbottom R-hadron search</a></li> <li><a href="86565?version=1&table=Table12">Stop R-hadron search</a></li> <li><a href="86565?version=1&table=Table13">Stau search</a></li> <li><a href="86565?version=1&table=Table14">Chargino search</a></li> <li><a href="86565?version=1&table=Table15">Meta-stable gluino R-hadron search</a></li> <li><a href="86565?version=1&table=Table17">Meta-stable gluino R-hadron search</a></li> </ul> <b>Acceptance and efficiency:</b> <ul> <li><a href="86565?version=1&table=Table16">MS-agnostic R-hadron search</a></li> </ul> <b>Truth quantities:</b> <ul> <li><a href="86565?version=1&table=Table18">Flavor composition of 800 GeV stop R-hadrons simulated using the generic model</a></li> <li><a href="86565?version=1&table=Table19">Flavor composition of 800 GeV anti-stop R-hadrons simulated using the generic model</a></li> <li><a href="86565?version=1&table=Table20">Flavor composition of 800 GeV stop R-hadrons simulated using the Regge model</a></li> <li><a href="86565?version=1&table=Table21">Flavor composition of 800 GeV anti-stop R-hadrons simulated using the Regge model</a></li> </ul> <b>Reinterpretation material:</b> <ul> <li><a href="86565?version=1&table=Table22">ETmiss trigger efficiency as function of true ETmiss</a></li> <li><a href="86565?version=1&table=Table23">Single-muon trigger efficiency as function of |eta| and beta</a></li> <li><a href="86565?version=1&table=Table24">Candidate reconstruction efficiency for ID+Calo selection</a></li> <li><a href="86565?version=1&table=Table25">Candidate reconstruction efficiency for loose selection</a></li> <li><a href="86565?version=1&table=Table26">Efficiency for a loose candidate to be promoted to a tight candidate</a></li> <li><a href="86565?version=1&table=Table27">Resolution and average of reconstructed dE/dx mass for a given simulated mass for ID+calo candidates</a></li> <li><a href="86565?version=1&table=Table28">Resolution and average of reconstructed ToF mass for a given simulated mass for ID+calo candidates</a></li> <li><a href="86565?version=1&table=Table29">Resolution and average of reconstructed ToF mass for a given simulated mass for FullDet candidates</a></li> </ul> <p><b>Pseudo-code snippets</b> and <b>example SLHA setups</b> are available in the "Resources" linked on the left, and more detailed reinterpretation material is available at <a href="http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/SUSY-2016-32/hepdata_info.pdf">http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/SUSY-2016-32/hepdata_info.pdf</a>.</p>

Lower mass requirement for signal regions.

More…

Searches for scalar leptoquarks and differential cross-section measurements in dilepton-dijet events in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}$ = 13 TeV with the ATLAS experiment

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Eur.Phys.J.C 79 (2019) 733, 2019.
Inspire Record 1718132 DOI 10.17182/hepdata.83968

Searches for scalar leptoquarks pair-produced in proton-proton collisions at $\sqrt{s}=13$ TeV at the Large Hadron Collider are performed by the ATLAS experiment. A data set corresponding to an integrated luminosity of 36.1 fb$^{-1}$ is used. Final states containing two electrons or two muons and two or more jets are studied, as are states with one electron or muon, missing transverse momentum and two or more jets. No statistically significant excess above the Standard Model expectation is observed. The observed and expected lower limits on the leptoquark mass at 95% confidence level extend up to 1.29 TeV and 1.23 TeV for first- and second-generation leptoquarks, respectively, as postulated in the minimal Buchm\"uller-R\"uckl-Wyler model, assuming a branching ratio into a charged lepton and a quark of 50%. In addition, measurements of particle-level fiducial and differential cross sections are presented for the $Z\rightarrow ee$, $Z\rightarrow\mu\mu$ and $t\bar{t}$ processes in several regions related to the search control regions. Predictions from a range of generators are compared with the measurements, and good agreement is seen for many of the observables. However, the predictions for the $Z\rightarrow\ell\ell$ measurements in observables sensitive to jet energies disagree with the data.

72 data tables

Inclusive cross-section and uncertainty from each source, for the dominant process in the each measurement region.

Differential cross-section and uncertainty from each source, as a function of leading $p_{T}^j$ for the dominant process in the $eejj$ measurement region.

Differential cross-section and uncertainty from each source, as a function of leading $p_{T}^j$ for the dominant process in the $\mu\mu jj$ measurement region.

More…

Search for low-mass resonances decaying into two jets and produced in association with a photon using $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Phys.Lett.B 795 (2019) 56-75, 2019.
Inspire Record 1717700 DOI 10.17182/hepdata.85763

A search is performed for localised excesses in dijet mass distributions of low-dijet-mass events produced in association with a high transverse energy photon. The search uses up to 79.8 fb$^{-1}$ of LHC proton-proton collisions collected by the ATLAS experiment at a centre-of-mass energy of 13 TeV during 2015-2017. Two variants are presented: one which makes no jet flavour requirements and one which requires both jets to be tagged as $b$-jets. The observed mass distributions are consistent with multi-jet processes in the Standard Model. The data are used to set upper limits on the production cross-section for a benchmark $Z^\prime$ model and, separately, on generic Gaussian-shape contributions to the mass distributions, extending the current ATLAS constraints on dijet resonances to the mass range between 225 and 1100 GeV.

16 data tables

Dijet mass distribution for the flavour inclusive category. Data, estimated background and uncertainties are shown. Events are collected using the single-photon trigger and contain a $E_T^{\gamma} > 150$ GeV photon and two $p_T^{jet} > 25$ GeV jets.

Dijet mass distribution for the flavour inclusive category. Data, estimated background and uncertainties are shown. Events are collected using the combined trigger and contain a $E_T^{\gamma} > 95$ GeV photon and two $p_T^{jet} > 65$ GeV jets.

Dijet mass distribution for the b-tagged category. Data, estimated background and uncertainties are shown. Events are collected using the single-photon trigger and contain a $E_T^{\gamma} > 150$ GeV photon and two $p_T^{jet} > 25$ GeV jets.

More…

Dijet azimuthal correlations and conditional yields in $pp$ and $p$+Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Phys.Rev.C 100 (2019) 034903, 2019.
Inspire Record 1717481 DOI 10.17182/hepdata.93905

This paper presents a measurement of forward-forward and forward-central dijet azimuthal angular correlations and conditional yields in proton-proton ($pp$) and proton-lead ($p$+Pb) collisions as a probe of the nuclear gluon density in regions where the fraction of the average momentum per nucleon carried by the parton entering the hard scattering is low. In these regions, gluon saturation can modify the rapidly increasing parton distribution function of the gluon. The analysis utilizes 25 pb$^{-1}$ of $pp$ data and 360 $\mu \mathrm{b}^{-1}$ of $p$+Pb data, both at $\sqrt{s_{\rm NN}}$ = 5.02 TeV, collected in 2015 and 2016, respectively, with the ATLAS detector at the LHC. The measurement is performed in the center-of-mass frame of the nucleon-nucleon system in the rapidity range between $-$4.0 and 4.0 using the two highest transverse momentum jets in each event, with the highest transverse momentum jet restricted to the forward rapidity range. No significant broadening of azimuthal angular correlations is observed for forward-forward or forward-central dijets in $p$+Pb compared to $pp$ collisions. For forward-forward jet pairs in the proton-going direction, the ratio of conditional yields in $p$+Pb collisions to those in $pp$ collisions is suppressed by approximately 20%, with no significant dependence on the transverse momentum of the dijet system. No modification of conditional yields is observed for forward-central dijets.

11 data tables

Unfolded azimuthal angular correlation distributions. Black markers represent p+Pb, red markers p+p

Unfolded width of azimuthal angular correlation distributions. Full markers represent p+Pb, open markers p+p

Unfolded Dijet conditional yields. Full markers represent p+Pb, open markers p+p

More…

Measurement of the ratio of cross sections for inclusive isolated-photon production in $pp$ collisions at $\sqrt s = 13$ and $8$ TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
JHEP 04 (2019) 093, 2019.
Inspire Record 1717495 DOI 10.17182/hepdata.89370

The ratio of the cross sections for inclusive isolated-photon production in $pp$ collisions at centre-of-mass energies of 13 and 8 TeV is measured using the ATLAS detector at the LHC. The integrated luminosities of the 13 TeV and 8 TeV datasets are 3.2 fb$^{-1}$ and 20.2 fb$^{-1}$, respectively. The ratio is measured as a function of the photon transverse energy in different regions of the photon pseudorapidity. The predictions from next-to-leading-order perturbative QCD calculations are compared with the measured ratio. The experimental systematic uncertainties as well as the uncertainties affecting the predictions are evaluated taking into account the correlations between the two centre-of-mass energies, resulting in a reduction of up to a factor of $2.5$ ($5$) in the experimental (theoretical) systematic uncertainties. The predictions based on several parameterisations of the proton parton distribution functions agree with the data within the reduced experimental and theoretical uncertainties. In addition, this ratio to that of the fiducial cross sections for $Z$ boson production at 13 and 8 TeV using the decay channels $Z \rightarrow e^+e^-$ and $Z \rightarrow \mu^+\mu^-$ is made and compared with the theoretical predictions. In this double ratio, a further reduction of the experimental uncertainty is obtained because the uncertainties arising from the luminosity measurement cancel out. The predictions describe the measurements of the double ratio within the theoretical and experimental uncertainties.

16 data tables

Measured ratio of cross sections for inclusive isolated-photon production as a function of $E_{\rm T}^{\gamma}$ for $|\eta^{\gamma}|<0.6$.

Predicted ratio of cross sections for inclusive isolated-photon production as a function of $E_{\rm T}^{\gamma}$ for $|\eta^{\gamma}|<0.6$.

Measured ratio of cross sections for inclusive isolated-photon production as a function of $E_{\rm T}^{\gamma}$ for $0.6<|\eta^{\gamma}|<1.37$.

More…

Search for scalar resonances decaying into $\mu^{+}\mu^{-}$ in events with and without $b$-tagged jets produced in proton-proton collisions at $\sqrt{s}=13$ TeV with the ATLAS detector

The ATLAS collaboration Aaboud, M. ; Aad, Georges ; Abbott, Brad ; et al.
JHEP 07 (2019) 117, 2019.
Inspire Record 1716572 DOI 10.17182/hepdata.84708

A search for a narrow scalar resonance decaying into an opposite-sign muon pair produced in events with and without $b$-tagged jets is presented in this paper. The search uses 36.1 fb$^{-1}$ of $\sqrt{s}= 13$ TeV proton-proton collision data recorded by the ATLAS experiment at the LHC. No significant excess of events above the expected Standard Model background is observed in the investigated mass range of 0.2 to 1.0 TeV. The observed upper limits at 95$\%$ confidence level on the cross section times branching ratio for $b$-quark associated production and gluon-gluon fusion are between 1.9 and 41 fb and 1.6 and 44 fb respectively, which is consistent with expectations.

6 data tables

The distribution of di-muon invariant mass in the b-tag signal region (SRbTag).

The distribution of di-muon invariant mass in the b-veto signal region (SRbVeto).

The 95% CL upper limits of the cross section times branching fraction of $\Phi \to \mu^+\mu^-$ for gluon-gluon fusion production

More…

Measurement of the $t\bar{t}Z$ and $t\bar{t}W$ cross sections in proton-proton collisions at $\sqrt{s}=13$ TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Phys.Rev.D 99 (2019) 072009, 2019.
Inspire Record 1713423 DOI 10.17182/hepdata.88175

A measurement of the associated production of a top-quark pair ($t\bar{t}$) with a vector boson ($W$, $Z$) in proton-proton collisions at a center-of-mass energy of 13 TeV is presented, using $36.1$ fb$^{-1}$ of integrated luminosity collected by the ATLAS detector at the Large Hadron Collider. Events are selected in channels with two same- or opposite-sign leptons (electrons or muons), three leptons or four leptons, and each channel is further divided into multiple regions to maximize the sensitivity of the measurement. The $t\bar{t}Z$ and $t\bar{t}W$ production cross sections are simultaneously measured using a combined fit to all regions. The best-fit values of the production cross sections are $\sigma_{t\bar{t}Z} = 0.95 \pm 0.08_{\mathrm{stat.}} \pm 0.10_{\mathrm{syst.}}$ pb and $\sigma_{t\bar{t}W} = 0.87 \pm 0.13_{\mathrm{stat.}} \pm 0.14_{\mathrm{syst.}}$ pb in agreement with the Standard Model predictions. The measurement of the $t\bar{t}Z$ cross section is used to set constraints on effective field theory operators which modify the $t\bar{t}Z$ vertex.

5 data tables

The result of the simultaneous fit to the $t\bar{t}Z$ and $t\bar{t}W$ cross sections.

68% confidence level (CL) contours of the measured $t\bar{t}Z$ and $t\bar{t}W$ cross sections.

95% confidence level (CL) contours of the measured $t\bar{t}Z$ and $t\bar{t}W$ cross sections.

More…

Observation of electroweak $W^{\pm}Z$ boson pair production in association with two jets in $pp$ collisions at $\sqrt{s} =$ 13 TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Phys.Lett.B 793 (2019) 469-492, 2019.
Inspire Record 1711223 DOI 10.17182/hepdata.83785

An observation of electroweak $W^{\pm}Z$ production in association with two jets in proton-proton collisions is presented. The data collected by the ATLAS detector at the Large Hadron Collider in 2015 and 2016 at a centre-of-mass energy of $\sqrt{s} =$ 13 TeV are used, corresponding to an integrated luminosity of 36.1 fb$^{-1}$. Events containing three identified leptons, either electrons or muons, and two jets are selected. The electroweak production of $W^{\pm}Z$ bosons in association with two jets is measured with an observed significance of 5.3 standard deviations. A fiducial cross-section for electroweak production including interference effects is measured to be $\sigma_{WZjj\mathrm{-EW}} = 0.57 \; ^{+ 0.14} _{- 0.13} \,(\mathrm{stat.}) \; ^{+ 0.07} _{- 0.06} \,(\mathrm{syst.}) \; \mathrm{fb}$. Total and differential fiducial cross-sections of the sum of $W^\pm Z jj$ electroweak and strong productions for several kinematic observables are also measured.

21 data tables

Fiducial cross section of the electroweak $W^{\pm}Z$ boson pair production in association with two jets. The first systematic uncertainty is experimental, the second is the theory modelling and interference systematics and the third one is the luminosity uncertainty.

Fiducial cross section of the $W^{\pm}Z$ boson pair production in association with two jets. The first systematic uncertainty is experimental, the second is the theory modelling and interference systematics and the third one is the luminosity uncertainty.

Numbers of observed and expected events in the $W^{\pm}Zjj$ signal region and in the three control regions, before the fit. The expected number of $WZjj-EW$ events from $SHERPA$ and the estimated number of background events from the other processes are shown. The sum of the background containing misidentified leptons is labelled "Misid. leptons". The total uncertainties are quoted.

More…

Properties of $g\rightarrow b\bar{b}$ at small opening angles in $pp$ collisions with the ATLAS detector at $\sqrt{s}=13$ TeV

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Phys.Rev.D 99 (2019) 052004, 2019.
Inspire Record 1711114 DOI 10.17182/hepdata.85697

The fragmentation of high-energy gluons at small opening angles is largely unconstrained by present measurements. Gluon splitting to $b$-quark pairs is a unique probe into the properties of gluon fragmentation because identified $b$-tagged jets provide a proxy for the quark daughters of the initial gluon. In this study, key differential distributions related to the $g\rightarrow b\bar{b}$ process are measured using 33 fb$^{-1}$ of $\sqrt{s}=13$ TeV $pp$ collision data recorded by the ATLAS experiment at the LHC in 2016. Jets constructed from charged-particle tracks, clustered with the anti-$k_t$ jet algorithm with radius parameter $R = 0.2$, are used to probe angular scales below the $R=0.4$ jet radius. The observables are unfolded to particle level in order to facilitate direct comparisons with predictions from present and future simulations. Multiple significant differences are observed between the data and parton shower Monte Carlo predictions, providing input to improve these predictions of the main source of background events in analyses involving boosted Higgs bosons decaying into $b$-quarks.

4 data tables

Normalisaed differential cross section, $(1/\sigma_\text{fid})d\sigma_\text{fid}/d\Delta R(b,b)$, as a function of $\Delta R(b,b)$ - the angle in $\eta$ and $\phi$ between the two b-tagged jets.

Normalisaed differential cross section, $(1/\sigma_\text{fid})d\sigma_\text{fid}/d\Delta\theta_\text{gpp,gbb}/\pi$, the angle between production (gpp) and decay (gbb) planes ($\Delta\theta_\text{gpp,gbb}$).

Normalisaed differential cross section, $(1/\sigma_\text{fid})d\sigma_\text{fid}/dz(p_\text{T})$, as a function of $z(p_\text{T})=p_\text{T,2}/(p_\text{T,1}+p_\text{T,2})$.

More…

Search for chargino and neutralino production in final states with a Higgs boson and missing transverse momentum at $\sqrt{s} = 13$ TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Phys.Rev.D 100 (2019) 012006, 2019.
Inspire Record 1711261 DOI 10.17182/hepdata.85726

A search is conducted for the electroweak pair production of a chargino and a neutralino $pp \rightarrow \tilde\chi^\pm_1 \tilde\chi^0_2$, where the chargino decays into the lightest neutralino and a $W$ boson, $\tilde\chi^\pm_1 \rightarrow \tilde\chi^0_1 W^{\pm}$, while the neutralino decays into the lightest neutralino and a Standard Model-like 125 GeV Higgs boson, $\tilde\chi^0_2 \rightarrow \tilde\chi^0_1 h$. Fully hadronic, semileptonic, diphoton, and multilepton (electrons, muons) final states with missing transverse momentum are considered in this search. Higgs bosons in the final state are identified by either two jets originating from bottom quarks ($h \rightarrow b\bar{b}$), two photons ($h \rightarrow \gamma\gamma$), or leptons from the decay modes $h \rightarrow WW$, $h \rightarrow ZZ$ or $h \rightarrow \tau \tau$. The analysis is based on 36.1 fb$^{-1}$ of $\sqrt{s} = 13$ TeV proton-proton collision data recorded by the ATLAS detector at the Large Hadron Collider. Observations are consistent with the Standard Model expectations, and 95% confidence-level limits of up to 680 GeV in $\tilde\chi^\pm_1/\tilde\chi^0_2$ mass are set in the context of a simplified supersymmetric model.

74 data tables

Data and SM predictions in SRs for the $0lb\bar{b}$ analysis for $E_{\mathrm{T}}^{\mathrm{miss}}$ in SRHad-High. All SRs selections but the one on the quantity shown are applied. All uncertainties are included in the uncertainty band. Two example SUSY models are superimposed for illustrative purposes.

Data and SM predictions in SRs for the $0lb\bar{b}$ analysis for $m_{b\bar{b}}$ in SRHad-Low. All SRs selections but the one on the quantity shown are applied. All uncertainties are included in the uncertainty band. Two example SUSY models are superimposed for illustrative purposes.

Data and SM predictions in SRs for the $1lb\bar{b}$ analysis for $m_{CT}$ in SR1Lbb-High. All SRs selections but the one on the quantity shown are applied. All uncertainties are included in the uncertainty band. Example SUSY models are superimposed for illustrative purposes.

More…

Search for heavy long-lived multi-charged particles in proton-proton collisions at $\sqrt{s}$ = 13 TeV using the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Phys.Rev.D 99 (2019) 052003, 2019.
Inspire Record 1707957 DOI 10.17182/hepdata.85615

A search for heavy long-lived multi-charged particles is performed using the ATLAS detector at the LHC. Data with an integrated luminosity of 36.1 fb$^{-1}$ collected in 2015 and 2016 from proton-proton collisions at $\sqrt{s}$ = 13 TeV are examined. Particles producing anomalously high ionization, consistent with long-lived massive particles with electric charges from |q|=2e to |q|=7e, are searched for. No events are observed, and 95% confidence level cross-section upper limits are interpreted as lower mass limits for a Drell-Yan production model. Multi-charged particles with masses between 50 GeV and 980-1220 GeV (depending on their electric charge) are excluded.

3 data tables

The signal efficiency values versus mass values for different charges.

Expected cross-section upper limits on the production cross-section of MCPs as a function of simulated particle mass for different charges.

Observed cross-section upper limits on the production cross-section of MCPs as a function of simulated particle mass for different charges.


Measurements of inclusive and differential fiducial cross-sections of $t\bar{t}\gamma$ production in leptonic final states at $\sqrt{s}$ = 13 TeV in ATLAS

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Eur.Phys.J.C 79 (2019) 382, 2019.
Inspire Record 1707015 DOI 10.17182/hepdata.88061

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.

20 data tables

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.

More…

Measurements of fiducial and differential cross-sections of $t\bar{t}$ production with additional heavy-flavour jets in proton-proton collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
JHEP 04 (2019) 046, 2019.
Inspire Record 1705857 DOI 10.17182/hepdata.87098

This paper presents measurements of $t\bar{t}$ production in association with additional $b$-jets in $pp$ collisions at the LHC at a centre-of-mass energy of 13 TeV. The data were recorded with the ATLAS detector and correspond to an integrated luminosity of 36.1 fb$^{-1}$. Fiducial cross-section measurements are performed in the dilepton and lepton-plus-jets $t\bar{t}$ decay channels. Results are presented at particle level in the form of inclusive cross-sections of $t\bar{t}$ final states with three and four $b$-jets as well as differential cross-sections as a function of global event properties and properties of $b$-jet pairs. The measured inclusive fiducial cross-sections generally exceed the $t\bar{t}b\bar{b}$ predictions from various next-to-leading-order matrix element calculations matched to a parton shower but are compatible within the total uncertainties. The experimental uncertainties are smaller than the uncertainties in the predictions. Comparisons of state-of-the-art theoretical predictions with the differential measurements are shown and good agreement with data is found for most of them.

50 data tables

The measured fiducial cross sections

The measured fiducial cross sections

Relative differential cross section as a function of the b-jet multiplicity in emu channel

More…