Measuring b-b correlations in ATLAS

The measurement of the relative production angle of b-b quark pairs serves as an excellent probe of QCD, particularly with regard to those contributions from higher order matrix elements. The very high rates of b production that will be achieved at the LHC will enable ATLAS to collect high statistics of b hadron decays, which offer the potential for high quality measurements of b-b correlations. Here, a novel technique is presented where one b quark direction is measured through the reconstruction of a J/y meson, and the other via its semi-leptonic decay to a muon. This technique potentially represents a considerable improvement on previous measurements that have used dimuon samples, where backgrounds are much higher and the presence of resonant decays to two muons demand the application of cuts on the mu-mu opening angle or invariant mass. The studies presented use a full simulation of the relevant components of the ATLAS detector to demonstrate the suitability of both the technique and the ATLAS instrumentation for making such a measurement. These results represent the beginning of an effort within the ATLAS collaboration to make a full study of the potential for measurements of b-b correlations at the LHC.