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

TY - JOUR

T1 - Measurement of the flavour composition of dijet events in pp collisions at root s=7 TeV with the ATLAS detector

AU - Aad, G.

AU - Abajyan, T.

AU - Abbott, B.

AU - Abdallah, J.

AU - Khalek, S.A.

AU - Dam, Mogens

AU - Hansen, Jørgen Beck

AU - Hansen, Peter Henrik

AU - Hansen, John Renner

AU - Hansen, Jørn Dines

AU - Heisterkamp, Simon Johann Franz

AU - Jørgensen, Morten Dam

AU - Boelaert, Nele Maria Philomena

AU - Klinkby, Esben Bryndt

AU - Løvschall-Jensen, Ask Emil

AU - Mehlhase, Sascha

AU - Nilsson, Björn Stefan

AU - Petersen, Troels Christian

AU - Xella, Stefania

PY - 2013/2/12

Y1 - 2013/2/12

N2 - This paper describes a measurement of the flavour composition of dijet events produced in pp collisions at √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.

AB - This paper describes a measurement of the flavour composition of dijet events produced in pp collisions at √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.

U2 - 10.1140/epjc/s10052-013-2301-5

DO - 10.1140/epjc/s10052-013-2301-5

M3 - Journal article

SN - 1434-6044

VL - 73

JO - European Physical Journal C

JF - European Physical Journal C

IS - 2

M1 - 2301

ER -