Measurement of the $B^{\pm}$ production asymmetry and the CP asymmetry in $B^{\pm} \to J/\psi K^{\pm}$ decays

Abstract

The $B^{\pm}$ meson production asymmetry in pp collisions is measured using $B^+ \to \overline{D}^0\pi^+$ decays. The data were recorded by the LHCb experiment during Run 1 of the LHC at center-of-mass energies of $\sqrt{s}$ = 7 and 8 TeV. The production asymmetries, integrated over transverse momenta in the range $2 < p_T < 30  GeV/c$, and rapidities in the range $2.1 < y < 4.5$ are measured to be
$\mathcal{A}_{prod}(B^+, \sqrt{s} = 7 TeV) = (−0.41 \pm 0.49 \pm 0.10) \times 10^{−2}$,
$\mathcal{A}_{prod}(B^+, \sqrt{s} = 8 TeV) = (−0.53 \pm 0.31 \pm 0.10) \times 10^{−2}$, where the first uncertainties are statistical and the second are systematic. These production asymmetries are used to correct the raw asymmetries of $B^+ \to J/\psi K^{\pm}$ decays, thus allowing a measurement of the CP asymmetry, $\mathcal{A}_{CP}(B^+ \to J/\psi K^{\pm}) = (0.09 \pm 0.27 \pm 0.07) \times 10^{−2}$.