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

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