Measurement of the ratio of the production cross sections times branching fractions of B < inf > c < /inf > < sup > ± < /sup > → J/ψπ < sup > ± < /sup > and B < sup > ± < /sup > → J/ψK < sup > ± < /sup > and (Formula presented.) in pp collisions at (Formula presented.) TeV

Abstract

The ratio of the production cross sections times branching fractions (Formula presented.)(Formula presented.) is studied in proton-proton collisions at a center-of-mass energy of 7 TeV with the CMS detector at the LHC. The kinematic region investigated requires Bc± and B± mesons with transverse momentum pT > 15 GeV and rapidity |y| < 1.6. The data sample corresponds to an integrated luminosity of 5.1 fb−1. The ratio is determined to be (Formula presented.)(Formula presented.). The Bc± → J/ψπ±π±π∓ decay is also observed in the same data sample. Using a model-independent method developed to measure the efficiency given the presence of resonant behaviour in the three-pion system, the ratio of the branching fractions (Formula presented.)(Formula presented.) is measured to be (Formula presented.)(Formula presented.), consistent with the previous LHCb result.[Figure not available: see fulltext.].