  A measurement of the angular correlations between beauty and anti-beauty
hadrons (B B-bar) 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 B B-bar production cross section, measured from a data sample
collected by CMS and corresponding to an integrated luminosity of 3.1 inverse
picobarns, shows that a sizable fraction of the B B-bar pairs are produced with
small opening angles. These studies provide a test of QCD and further insight
into the dynamics of b b-bar production.
