Measurement of the $C¶$ asymmetry in $B^+ \rightarrow K^+ μ^+ μ^-$ decays

Abstract

A measurement of the $C¶$ asymmetry in $B^+ \rightarrow K^+ μ^+ μ^-$ decays is presented using $pp$ collision data, corresponding to an integrated luminosity of 1.0${\,fb}^{-1}$, recorded by the LHCb experiment during 2011 at a centre-of-mass energy of 7 TeV. The measurement is performed in seven bins of $μ^+ μ^-$ invariant mass squared in the range ${0.05<q^{2}<22.00{\mathrm{GeV^2/}c^4}}$, excluding the ${J/ψ}$ and $ψ{(2S)}$ resonance regions. Production and detection asymmetries are corrected for using the $B^+ \rightarrow J/ψK^+$ decay as a control mode. Averaged over all the bins, the $C¶$ asymmetry is found to be ${{\cal A}_{C¶} = 0.000\pm 0.033{(stat.)} \pm0.005 {(syst.)} \pm 0.007{}(J/ψK^+)}$, where the third uncertainty is due to the $C¶$ asymmetry of the control mode. This is consistent with the Standard Model prediction.

16 pages including author list, 2 figures