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Paper   IPM / Particles / 11766
School of Particles and Accelerator
Title:   Measurement of B anti-B Angular Correlations based on Secondary Vertex Reconstruction at sqrt(s)=7 TeV
Author(s):
 1 Hessamaddin Arfaei 2 Hamed Bakhshiansohi 3 Seyed Mohsen Etesami 4 Ali Fahim 5 Majid Hashemi 6 Abideh Jafari 7 Mohsen Khakzad 8 A Mohammadi 9 Mojtaba Mohammadi Najafabadi 10 Saeid Paktinat Mehdiabadi 11 Batool Safarzadeh 12 Maryam Zeinali
Status:   Published
Journal: JHEP
No.:  136
Vol.:  1103
Year:  2011
Supported by:  IPM
Abstract:
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.