Journal of High Energy Physics
A measurement of the angular correlations between beauty and anti-beauty hadrons (BB¯) produced in pp collisions at a centre-of-mass energy of 7 TeV at the CERN LHC is presented, probing for the first time the region of small angular separation. The B hadrons are identified by the presence of displaced secondary vertices from their decays. The B hadron angular separation is reconstructed from the decay vertices and the primary-interaction vertex. The differential BB¯ production cross section, measured from a data sample collected by CMS and corresponding to an integrated luminosity of 3.1 pb−1, shows that a sizable fraction of the BB¯ pairs are produced with small opening angles. These studies provide a test of QCD and further insight into the dynamics of bb¯ production.
Khachatryan, Vardan; Baarmand, Marc M.; Dorney, B.; Guragain, Samir; Hohlmann, Marcus; Kalakhety, Himali; Ralich, Robert M.; Vodopiyanov, Igor; and The CMS Collaboration, "Measurement Of BB̄ Angular Correlations Based On Secondary Vertex Reconstruction At √s = 7 TeV" (2011). Aerospace, Physics, and Space Science Faculty Publications. 576.