Date

Collaboration

Search for New Phenomena in Dijet Angular Distributions in Proton-Proton Collisions at $\sqrt{s} = 8$ TeV Measured with the ATLAS Detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abdallah, Jalal ; et al.
Phys.Rev.Lett. 114 (2015) 221802, 2015.
Inspire Record 1357594 DOI 10.17182/hepdata.68404

A search for new phenomena in LHC proton-proton collisions at a center-of-mass energy of $\sqrt{s}=8$ TeV was performed with the ATLAS detector using an integrated luminosity of 17.3 fb$^{-1}$. The angular distributions are studied in events with at least two jets; the highest dijet mass observed is 5.5 TeV. All angular distributions are consistent with the predictions of the Standard Model. In a benchmark model of quark contact interactions, a compositeness scale below 8.1 TeV in a destructive interference scenario and 12.0 TeV in a constructive interference scenario is excluded at 95 % CL; median expected limits are 8.9 TeV for the destructive interference scenario and 14.1 TeV for the constructive interference scenario.

7 data tables match query

mjj region 600 - 800 GeV. The observed systematic is the experimental uncertainty, while the SM prediction systematic is the theoretical uncertainty.

mjj region 800 - 1200 GeV. The observed systematic is the experimental uncertainty, while the SM prediction systematic is the theoretical uncertainty.

mjj region 1200 - 1600 GeV. The observed systematic is the experimental uncertainty, while the SM prediction systematic is the theoretical uncertainty.

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Measurement of the flavour composition of dijet events in pp collisions at sqrt{s}=7 TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abajyan, Tatevik ; Abbott, Brad ; et al.
Eur.Phys.J.C 73 (2013) 2301, 2013.
Inspire Record 1188891 DOI 10.17182/hepdata.68119

This paper describes a measurement of the flavour composition of dijet events produced in pp collisions at sqrt{s}=7 TeV using the ATLAS detector. The measurement uses the full 2010 data sample, corresponding to an integrated luminosity of 39 pb^-1. Six possible combinations of light, charm and bottom jets are identified in the dijet events, where the jet flavour is defined by the presence of bottom, charm or solely light flavour hadrons in the jet. Kinematic variables, based on the properties of displaced decay vertices and optimised for jet flavour identification, are used in a multidimensional template fit to measure the fractions of these dijet flavour states as functions of the leading jet transverse momentum in the range 40 GeV to 500 GeV and jet rapidity |y| < 2.1. The fit results agree with the predictions of leading- and next-to-leading-order calculations, with the exception of the dijet fraction composed of bottom and light flavour jets, which is underestimated by all models at large transverse jet momenta. The ability to identify jets containing two b-hadrons, originating from e.g. gluon splitting, is demonstrated. The difference between bottom jet production rates in leading and subleading jets is consistent with the next-to-leading-order predictions.

6 data tables match query

No description provided.

No description provided.

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Measurements of jet vetoes and azimuthal decorrelations in dijet events produced in $pp$ collisions at $\sqrt{s}$ = 7 TeV using the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abdallah, Jalal ; et al.
Eur.Phys.J.C 74 (2014) 3117, 2014.
Inspire Record 1307243 DOI 10.17182/hepdata.66091

Additional jet activity in dijet events is measured using $pp$ collisions at ATLAS at a centre-of-mass energy of 7 TeV, for jets reconstructed using the anti-kt algorithm with radius parameter R=0.6. This is done using variables such as the fraction of dijet events without an additional jet in the rapidity interval bounded by the dijet subsystem and correlations between the azimuthal angles of the dijets. They are presented, both with and without a veto on additional jet activity in the rapidity interval, as a function of the mean transverse momentum of the dijets and of the rapidity interval size. The double differential dijet cross section is also measured as a function of the interval size and the azimuthal angle between the dijets. These variables probe differences in the approach to resummation of large logarithms when performing QCD calculations. The data are compared to POWHEG, interfaced to the PYTHIA 8 and HERWIG parton shower generators, as well as to HEJ with and without interfacing it to the ARIADNE parton shower generator. None of the theoretical predictions agree with the data across the full phase-space considered; however, POWHEG+PYTHIA 8 and HEJ+ARIADNE are found to provide the best agreement with the data.These measurements use the full data sample collected with the ATLAS detector in 7 TeV $pp$ collisions at the LHC and correspond to integrated luminosities of 36.1 pb$^-1$ and 4.5 fb$^-1$ for data collected during 2010 and 2011 respectively.

40 data tables match query

Gap fraction as a function of leading dijet rapidity separation.

Gap fraction as a function of leading dijet scalar mean pT in GeV.

Mean number of jets in rapidity interval as a function of leading dijet rapidity separation.

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Measurement of the underlying event in jet events from 7 TeV proton-proton collisions with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abajyan, Tatevik ; Abbott, Brad ; et al.
Eur.Phys.J.C 74 (2014) 2965, 2014.
Inspire Record 1298811 DOI 10.17182/hepdata.65229

Distributions sensitive to the underlying event in QCD jet events have been measured with the ATLAS detector at the LHC, based on 37/pb of proton-proton collision data collected at a centre-of-mass energy of 7 TeV. Charged-particle mean $p_T$ and densities of all-particle $E_T$ and charged-particle multiplicity and $p_T$ have been measured in regions azimuthally transverse to the hardest jet in each event. These are presented both as one-dimensional distributions and with their mean values as functions of the leading-jet transverse momentum from 20 GeV to 800 GeV. The correlation of charged-particle mean $p_T$ with charged-particle multiplicity is also studied, and the $E_T$ densities include the forward rapidity region; these features provide extra data constraints for Monte Carlo modelling of colour reconnection and beam-remnant effects respectively. For the first time, underlying event observables have been computed separately for inclusive jet and exclusive dijet event selections, allowing more detailed study of the interplay of multiple partonic scattering and QCD radiation contributions to the underlying event. Comparisons to the predictions of different Monte Carlo models show a need for further model tuning, but the standard approach is found to generally reproduce the features of the underlying event in both types of event selection.

36 data tables match query

Transverse $\langle \sum p_T^\text{ch} / \delta\eta\,\delta\phi \rangle$ vs. $p_T^\text{lead}$ in $|\eta| < 2.5$ in incl jet / excl dijet events.

Trans-max $\langle \sum p_T^\text{ch} / \delta\eta\,\delta\phi \rangle$ vs. $p_T^\text{lead}$ in $|\eta| < 2.5$ in incl jet / excl dijet events.

Trans-min $\langle \sum p_T^\text{ch} / \delta\eta\,\delta\phi \rangle$ vs. $p_T^\text{lead}$ in $|\eta| < 2.5$ in incl jet / excl dijet events.

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Measurement of inclusive jet and dijet cross sections in proton-proton collisions at 7 TeV centre-of-mass energy with the ATLAS detector

The ATLAS collaboration Aad, G. ; Abbott, B. ; Abdallah, J. ; et al.
Eur.Phys.J.C 71 (2011) 1512, 2011.
Inspire Record 871366 DOI 10.17182/hepdata.56004

Jet cross sections have been measured for the first time in proton-proton collisions at a centre-of-mass energy of 7 TeV using the ATLAS detector. The measurement uses an integrated luminosity of 17 nb-1 recorded at the Large Hadron Collider. The anti-kt algorithm is used to identify jets, with two jet resolution parameters, R = 0.4 and 0.6. The dominant uncertainty comes from the jet energy scale, which is determined to within 7% for central jets above 60 GeV transverse momentum. Inclusive single-jet differential cross sections are presented as functions of jet transverse momentum and rapidity. Dijet cross sections are presented as functions of dijet mass and the angular variable $\chi$. The results are compared to expectations based on next-to-leading-order QCD, which agree with the data, providing a validation of the theory in a new kinematic regime.

26 data tables match query

Inclusive jet double-differential cross sections in the |rapidity| range 0 to 0.3, using a jet resolution R value of 0.4. The three (sys) errors are respectively, the Absolute JES, the Unfolding and the Luminosity uncertainties.

Inclusive jet double-differential cross sections in the |rapidity| range 0.3 to 0.8, using a jet resolution R value of 0.4. The three (sys) errors are respectively, the Absolute JES, the Unfolding and the Luminosity uncertainties.

Inclusive jet double-differential cross sections in the |rapidity| range 0.8 to 1.2, using a jet resolution R value of 0.4. The three (sys) errors are respectively, the Absolute JES, the Unfolding and the Luminosity uncertainties.

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Search for Quark Contact Interactions in Dijet Angular Distributions in pp Collisions at sqrt(s) = 7 TeV Measured with the ATLAS Detector

The ATLAS collaboration Aad, G. ; Abbott, B. ; Abdallah, J. ; et al.
Phys.Lett.B 694 (2011) 327-345, 2011.
Inspire Record 871487 DOI 10.17182/hepdata.57022

Dijet angular distributions from the first LHC pp collisions at center-of-mass energy sqrt(s) = 7 TeV have been measured with the ATLAS detector. The dataset used for this analysis represents an integrated luminosity of 3.1 pb-1. Dijet $\chi$ distributions and centrality ratios have been measured up to dijet masses of 2.8 TeV, and found to be in good agreement with Standard Model predictions. Analysis of the $\chi$ distributions excludes quark contact interactions with a compositeness scale $\Lambda$ below 3.4 TeV, at 95% confidence level, significantly exceeding previous limits.

5 data tables match query

CHI distribution for mass bin 340 to 520 GeV.

CHI distribution for mass bin 520 to 800 GeV.

CHI distribution for mass bin 800 to 1200 GeV.

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Search for New Particles in Two-Jet Final States in 7 TeV Proton-Proton Collisions with the ATLAS Detector at the LHC

The ATLAS collaboration Aad, G. ; Abbott, B. ; Abdallah, J. ; et al.
Phys.Rev.Lett. 105 (2010) 161801, 2010.
Inspire Record 865423 DOI 10.17182/hepdata.57036

A search for new heavy particles manifested as resonances in two-jet final states is presented. The data were produced in 7 TeV proton-proton collisions by the Large Hadron Collider (LHC) and correspond to an integrated luminosity of 315 nb^-1 collected by the ATLAS detector. No resonances were observed. Upper limits were set on the product of cross section and signal acceptance for excited-quark (q*) production as a function of q* mass. These exclude at the 95% CL the q* mass interval 0.30 < mq* < 1.26 TeV, extending the reach of previous experiments.

2 data tables match query

The dijet mass distribution (NUMBER OF EVENTS).

95 PCT CL upper limit of the cross section x acceptance.


Measurement of ttbar production with a veto on additional central jet activity in pp collisions at sqrt(s) = 7 TeV using the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abdallah, Jalal ; et al.
Eur.Phys.J.C 72 (2012) 2043, 2012.
Inspire Record 1094568 DOI 10.17182/hepdata.58936

A measurement of the jet activity in ttbar events produced in proton-proton collisions at a centre-of-mass energy of 7 TeV is presented, using 2.05 fb^-1 of integrated luminosity collected by the ATLAS detector at the Large Hadron Collider. The ttbar events are selected in the dilepton decay channel with two identified b-jets from the top quark decays. Events are vetoed if they contain an additional jet with transverse momentum above a threshold in a central rapidity interval. The fraction of events surviving the jet veto is presented as a function of this threshold for four different central rapidity interval definitions. An alternate measurement is also performed, in which events are vetoed if the scalar transverse momentum sum of the additional jets in each rapidity interval is above a threshold. In both measurements, the data are corrected for detector effects and compared to the theoretical models implemented in MC@NLO, POWHEG, ALPGEN and SHERPA. The experimental uncertainties are often smaller than the spread of theoretical predictions, allowing deviations between data and theory to be observed in some regions of phase space.

16 data tables match query

The measured fraction of events, the gap fraction, surviving the veto cut of having no additional jets in the |rapidity| interval < 0.8 having a transverse momentum greater than Q, as a function of Q.

The measured fraction of events, the gap fraction, surviving the veto cut of having no additional jets in the |rapidity| interval 0.8-1.5 having a transverse momentum greater than Q, as a function of Q.

The measured fraction of events, the gap fraction, surviving the veto cut of having no additional jets in the |rapidity| interval 1.5-2.1 having a transverse momentum greater than Q, as a function of Q.

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Measurement of Dijet Azimuthal Decorrelations in pp Collisions at sqrt(s)=7 TeV

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abdallah, Jalal ; et al.
Phys.Rev.Lett. 106 (2011) 172002, 2011.
Inspire Record 889546 DOI 10.17182/hepdata.58478

Azimuthal decorrelations between the two central jets with the largest transverse momenta are sensitive to the dynamics of events with multiple jets. We present a measurement of the normalized differential cross section based on the full dataset (L=36/pb) acquired by the ATLAS detector during the 2010 sqrt(s)=7 TeV proton-proton run of the LHC. The measured distributions include jets with transverse momenta up to 1.3 TeV, probing perturbative QCD in a high energy regime.

9 data tables match query

Distribution for the maxPT jet (P=3) from 110 to 160 GeV.

Distribution for the maxPT jet (P=3) from 160 to 210 GeV.

Distribution for the maxPT jet (P=3) from 210 to 260 GeV.

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Measurement of inclusive jet and dijet production in $pp$ collisions at $\sqrt{s}=7$ TeV using the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abdallah, Jalal ; et al.
Phys.Rev.D 86 (2012) 014022, 2012.
Inspire Record 1082936 DOI 10.17182/hepdata.58163

Inclusive jet and dijet cross sections have been measured in proton-proton collisions at a centre-of-mass energy of 7 TeV using the ATLAS detector at the Large Hadron Collider. The cross sections were measured using jets clustered with the anti-kT algorithm with parameters R=0.4 and R=0.6. These measurements are based on the 2010 data sample, consisting of a total integrated luminosity of 37 inverse picobarns. Inclusive jet double-differential cross sections are presented as a function of jet transverse momentum, in bins of jet rapidity. Dijet double-differential cross sections are studied as a function of the dijet invariant mass, in bins of half the rapidity separation of the two leading jets. The measurements are performed in the jet rapidity range |y|<4.4, covering jet transverse momenta from 20 GeV to 1.5 TeV and dijet invariant masses from 70 GeV to 5 TeV. The data are compared to expectations based on next-to-leading order QCD calculations corrected for non-perturbative effects, as well as to next-to-leading order Monte Carlo predictions. In addition to a test of the theory in a new kinematic regime, the data also provide sensitivity to parton distribution functions in a region where they are currently not well-constrained.

32 data tables match query

Inclusive jet PT distribution for the |y| range 0.0-0.3 and R=0.4.

Inclusive jet PT distribution for the |y| range 0.3-0.8 and R=0.4.

Inclusive jet PT distribution for the |y| range 0.8-1.2 and R=0.4.

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