Measurement of the relative B^±_c/B^± production cross section with the ATLAS detector at √s = 8 TeV

The total cross section and differential cross sections for the production of B^±_c mesons, times their branching fraction to J/ψπ^±, are measured relative to those for the production of B^± mesons, times their branching fraction to J/ψK^±. The data used for this study correspond to an integrated luminosity of 20.3fb⁻¹ of pp collisions recorded by the ATLAS detector at the Large Hadron Collider in 2012 at a center-of-mass energy of √s = 8 TeV. The measurement is performed differentially in bins of transverse momentum p_T for 13 GeV < p_T(B^±_c) < 22 GeV and p_T(B^±_c) > 22 GeV and in bins of rapidity y for |y| < 0.75 and 0.75 < |y| <2.3. The relative cross section times branching fraction for the full range p_T > 13 GeV and |y| < 2.3 is (0.34 ± 0.04_stat^+0.06_{−0.02 sys} ± 0.01_lifetime)%. The differential measurements suggest that the production cross section of the B^±_c decreases faster with p_T than the production cross section of the B^±, while no significant dependence on rapidity is observed.