Measurement of the $B^{\pm }$ production cross-section in pp collisions at $\sqrt{s}=$ 7 and 13 TeV

Abstract

The production of $B^{\pm }$ mesons is studied in $pp$ collisions at centre-of-mass energies of 7 and 13 TeV, using $B^{\pm }\to J/\ddot{I}ˆK^{\pm }$ decays and data samples corresponding to 1.0 fb${}^{-1}$ and 0.3 fb${}^{-1}$, respectively. The production cross-sections summed over both charges and integrated over the transverse momentum range $0<p_{\text{T}}<40$ GeV/$c$ and the rapidity range $2.0<y<4.5$ are measured to be $\ddot{I}ƒ(pp\to B^{\pm }X,\sqrt{s}=\text{7 TeV})=43.0\pm 0.2\pm 2.5\pm 1.7\hat{I}¼b,$ $\ddot{I}ƒ(pp\to B^{\pm }X,\sqrt{s}=\text{13 TeV})=86.6\pm 0.5\pm 5.4\pm 3.4\hat{I}¼b,$ where the first uncertainties are statistical, the second are systematic, and the third are due to the limited knowledge of the $B^{\pm }\to J/\ddot{I}ˆK^{\pm }$ branching fraction. The ratio of the cross-section at 13 TeV to that at 7 TeV is determined to be $2.02\pm 0.02\text{(stat)}\pm 0.12\text{(syst)}$. Differential cross-sections are also reported as functions of $p_{\text{T}}$ and $y$. All results are in agreement with theoretical calculations based on the state-of-art fixed next-to-leading order quantum chromodynamics.

All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2017-037.html