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