$B$ flavour tagging using charm decays at the LHCb experiment

Abstract

An algorithm is described for tagging the flavour content at production of neutral $B$ mesons in the LHCb experiment. The algorithm exploits the correlation of the flavour of a $B$ meson with the charge of a reconstructed secondary charm hadron from the decay of the other $b$ hadron produced in the proton-proton collision. Charm hadron candidates are identified in a number of fully or partially reconstructed Cabibbo-favoured decay modes. The algorithm is calibrated on the self-tagged decay modes $B^{+}\to J/\ddot{I}ˆK^{+}$ and $B^0\to J/\ddot{I}ˆK^{\ast 0}$ using $3.0{\mathrm{fb}}^{-1}$ of data collected by the LHCb experiment at $pp$ centre-of-mass energies of $7\mathrm{TeV}$ and $8\mathrm{TeV}$. Its tagging power on these samples of $B\to J/\ddot{I}ˆX$ decays is $(0.30\pm 0.01\pm 0.01)\%$.

All figures and tables, along with any supplementary material and additional information, are available at http://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-027.html