Abstract
Abstract A search for quark compositeness using dijet angular distributions from pp collisions at $ \sqrt {s} = 7 $ TeV is presented. The search has been carried out using a data sample corresponding to an integrated luminosity of 2.2 fb−1, recorded by the CMS experiment at the LHC. Normalized dijet angular distributions have been measured for dijet invariant masses from 0.4 TeV to above 3 TeV and compared with a variety of contact interaction models, including those which take into account the effects of next-to-leading-order QCD corrections. The data are found to be in agreement with the predictions of perturbative QCD, and lower limits are obtained on the contact interaction scale, ranging from 7.5 up to 14.5 TeV at 95 % confidence level.
Highlights
Collisions at s = 7 TeV is presented
Models of quark compositeness may explain the number of quark generations, quark charges, and quark masses, which are not predicted in the standard model
A common signature of quark compositeness models is the appearance of new interactions between quark constituents at a characteristic scale Λ that is much larger than the quark masses
Summary
The use of the variable χdijet is motivated by the fact that dσdijet/dχdijet is approximately uniform for QCD dijet processes, while CI models predict angular distributions that are strongly peaked at low values of χdijet. The lower limits of the Mjj ranges for the dijet angular distributions were chosen such that the trigger efficiencies exceed 99%, and are given by the values 0.4, 0.6, 0.8, 1.0, 1.2, 1.5, 1.9, 2.4, and 3.0 TeV.
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