Measurement on B-hadron angular correlations with CMS

A measurement of the angular correlations between beauty and anti-beauty hadrons produced in LHC pp collisions at sqrt{s}=7 TeV is presented, probing for the first time the small angular separation region. The B hadrons are identified by the presence of secondary vertices from their decays and their kinematics reconstructed combining the decay vertex with the primary interaction vertex. The results are compared with predictions based on perturbative QCD calculations at leading and next-to-leading order.