Observation of very large transverse momentum jets at the CERN p collider

Banner, M.; Bloch, P.; Bonaudi, Franco; Borer, K.; Borghini, M.; Chollet, J.C.; Clark, A.; Conta, C.; Darriulat, P.; Lella, L. Di; Dines-Hansen, J.; Dorsaz, P.A.; Fayard, L.; Fraternali, M.; Froidevaux, D.; Gaillard, J. M.; Gildemeister, O.; Goggi, V. G.; Grote, H.; Hahn, B.; Hänni, H.; Hansen, J. R.; Hansen, P. H.; Himel, T.; Hungerbühler, V.; Jenni, P.; Kofoed‐Hansen, O.; Livan, M.; Loucatos, S.; Madsen, B.; Mansoulié, B.; Mantovani, G.; Mapelli, L.; Merkel, B.; Mermikides, M.; Möllerud, R.; Nilsson, B.S.; Onions, C.; Parrour, G.; Pastore, F.; Plothow‐Besch, H.; Repellin, J. P.; Ringel, Jeanne S.; Rothenberg, A.; Roussarie, A.; Sauvage, G.; Schacher, J.; Siegrist, J.; Stocker, F.; Tieger, J.; Vercesi, V.; Williams, H. H.; Zaccone, H.; Zeller, W.

doi:10.1016/0370-2693(82)90629-3

Cited by 162 publications

(21 citation statements)

References 17 publications

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“…The measurement of the inclusive jet cross section is a benchmark of the standard model (SM) at hadron colliders [1,2]. At the Large Hadron Collider (LHC), jets produced in the high center-of-mass energy collisions test the SM at the smallest distance scales presently possible can constrain parton momentum distributions in the proton and are sensitive to the strong coupling constant.…”

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confidence: 99%

“…The measured cross section extends to the highest values of jet p T ever observed and, within the experimental and theoretical uncertainties, is generally in agreement with next-to-leadingorder perturbative QCD predictions. DOI: 10.1103/PhysRevLett.107.132001 PACS numbers: 13.85.Àt, 12.38.Bx The measurement of the inclusive jet cross section is a benchmark of the standard model (SM) at hadron colliders [1,2]. At the Large Hadron Collider (LHC), jets produced in the high center-of-mass energy collisions test the SM at the smallest distance scales presently possible can constrain parton momentum distributions in the proton and are sensitive to the strong coupling constant.…”

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confidence: 99%

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Measurement of the Inclusive Jet Cross Section inppCollisions ats=7 TeV

Chatrchyan¹,

Khachatryan²,

Sirunyan³

et al. 2011

Phys. Rev. Lett.

128

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The inclusive jet cross section is measured in pp collisions with a center-of-mass energy of 7 TeV at the Large Hadron Collider using the CMS experiment. The data sample corresponds to an integrated luminosity of 34 pb À1 . The measurement is made for jet transverse momenta in the range 18-1100 GeVand for absolute values of rapidity less than 3. The measured cross section extends to the highest values of jet p T ever observed and, within the experimental and theoretical uncertainties, is generally in agreement with next-to-leadingorder perturbative QCD predictions. DOI: 10.1103/PhysRevLett.107.132001 PACS numbers: 13.85.Àt, 12.38.Bx The measurement of the inclusive jet cross section is a benchmark of the standard model (SM) at hadron colliders [1,2]. At the Large Hadron Collider (LHC), jets produced in the high center-of-mass energy collisions test the SM at the smallest distance scales presently possible can constrain parton momentum distributions in the proton and are sensitive to the strong coupling constant. Significant deviations from predictions of the inclusive jet cross section at high transverse momentum p T could also be an indication of new phenomena beyond the SM. Results from the Tevatron p " p collider demonstrate agreement with nextto-leading-order (NLO) theoretical predictions from perturbative quantum chromodynamics (pQCD) for jets in the approximate p T range of 50-700 GeV, using about 1 fb Early results from the ATLAS Collaboration for jets in the p T range 60-600 GeV, based on a 17 pb À1 data sample of pp collisions at ffiffi ffi s p ¼ 7 TeV at the LHC [6], also indicate agreement with theoretical predictions. Using a data sample corresponding to 34 pb À1 of integrated luminosity from pp collisions recorded by the CMS detector at the LHC with ffiffi ffi s p ¼ 7 TeV, we significantly extend the p T range from previous measurements of the inclusive jet p T spectrum to 18-1100 GeV and for rapidities jyj < 3:0. The rapidity y is defined as y ¼ 1 2 ln½ðE þ p z Þ=ðE À p z Þ, where E is the jet energy and p z is the component of the jet momentum along the beam axis. The inclusive jet cross section is defined as d 2 jet =ðdp T dyÞ ¼ N jet = ðÁp T ÁyÞ½1=ðLÞ, where N jet is the number of jets per bin, Áp T and Áy are the bin widths in p T and y, L is the total integrated luminosity, and is the product of event and jet selection efficiencies. All jets with p T > 18 GeV in a proton-proton collision event are used in the measurement. In this Letter, the inclusive jet cross section is compared with theoretical predictions at NLO in pQCD.The CMS detector has silicon pixel and microstrip trackers covering pseudorapidities up to jj ¼ 2:5, where ¼ À ln½tanð=2Þ and is the polar angle relative to the counterclockwise proton beam direction. Together with a 3.8 T solenoid, the trackers enable track reconstruction down to transverse momenta of about 100 MeV and a resolution of about 1% at 100 GeV. A high-granularity electromagnetic crystal calorimeter (ECAL) extends up to jj ¼ 3:0 and has an energy resolution o...

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confidence: 99%

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confidence: 99%

Measurement of the Inclusive Jet Cross Section inppCollisions ats=7 TeV

Chatrchyan¹,

Khachatryan²,

Sirunyan³

et al. 2011

Phys. Rev. Lett.

128

View full text Add to dashboard Cite

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“…Evidence for similar processes at a hadron collider required another 7 years for a suitable experimental apparatus to develop [26,64]. The evidence came in the form of 2 → 2 processes, or so-called "di-jet" events such as the one shown in Figure 2.4 from the UA2 experiment at the CERN SppS collider.…”

Section: Jet Physics and Phenomenologymentioning

confidence: 99%

“…meson (Fermilab) ! lepton (SLAC) J/" meson (SLAC and BNL) Quarks (SLAC) !, " (BNL) K (Manchester) through the extensive experience at past colliders such as SPEAR at SLAC [20,21], the PETRA storage ring at DESY [22,23], the Stanford Linear Collider (SLC) at SLAC [24,25], the SppS [26,27], PEP-II at SLAC [28,29], the Large ElectronPositron (LEP) collider at CERN [30,31,32,33], and the Tevatron collider at Fermilab [34,35,36]. For a comparison of these machines and their design parameters see [37].…”

Section: Introductionmentioning

confidence: 99%

Measurement of Hadronic Event Shapes and Jet Substructure in Proton-Proton Collisions at 7.0 TeV Center-of-Mass Energy with the ATLAS Detector at the Large Hadron Collider

Miller¹

2012

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This thesis presents the first measurement of 6 hadronic event shapes in proton-proton collisions at a center-of-mass energy of √ s = 7 TeV using the ATLAS detector at the Large Hadron Collider. Results are presented at the particle-level, permitting comparisons to multiple Monte Carlo event generator tools. Numerous tools and techniques that enable detailed analysis of the hadronic final state at high luminosity are described. The approaches presented utilize the dual strengths of the ATLAS calorimeter and tracking systems to provide high resolution and robust measurements of the hadronic jets that constitute both a background and a signal throughout AT-LAS physics analyses. The study of the hadronic final state is then extended to jet substructure, where the energy flow and topology within individual jets is studied at the detector level and techniques for estimating systematic uncertainties for such measurements are commissioned in the first data. These first substructure measurements in ATLAS include the jet mass and sub-jet multiplicity as well as those concerned with multi-body hadronic decays and color flow within jets. Finally, the first boosted hadronic object observed at the LHC -the decay of the top quark to a single jet -is presented. PrefaceThe Large Hadron Collider (LHC) is the largest machine ever built by humankind and is designed to accelerate protons to the highest energies ever produced on Earth.This fact alone merits respect and awe of the infinite creativity and willingness of humans to believe that they can achieve the impossible in order to understand the unknowable. The possibility to study the properties of the interactions that such a machine produces is truly a once in a lifetime opportunity.The work constituted by this thesis represents an endeavor to understand the way that quarks and gluons -the partons that were at one time only a theoretical "convenience" for Richard Feynman, Murray Gell-Mann and George Zweig -evolve to form experimental signatures in our detectors, the jets of the so-called hadronic final state. But the LHC is a unique machine, producing a complex environment in which these signatures are manifested. As a result, techniques must be developed to tease out the interesting physics buried within a complex milieu created by the enormous energy and intensity of the LHC. This thesis is at least in part devoted to describing those tools, some of which have since come to be used in analyses measuring the top quark, the W boson, and searches for new physics throughout ATLAS.An attempt is made to draw a connection among the many studies performed throughout the initial phases of the ATLAS experiment. Critical efforts during the commissioning of the detector, the first acquisition of √ s = 900 GeV and then √ s = 7 TeV data, and the full-fledged analysis of the full 2010 dataset, are all tied together by a common thread: the ability to utilize the largest and most advance instruments ever built in a coherent manner to understand the highest energy collisions of the sm...

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“…As the center-ofmass energy increases, the number of produced particles increases and events get more complex. Although the discovery of high transverse energy, E T , jets in hadron collisions at the CERN ISR [1] and Sp " pS Collider [2] supported the theory of strongly interacting quarks and gluons (QCD), low-p T hadron production is still not well understood despite additional data from p " p and pp colliders including RHIC [3] because the strong coupling is large, and perturbative QCD calculations do not apply. Phenomenological models, such as PYTHIA [4], have been developed and tuned to data.…”

Section: Introductionmentioning

confidence: 99%