Measurement of $D_s^{pm}$ production asymmetry in $pp$ collisions at $sqrt{s} =7$ and 8 TeV

The inclusive $D_s^{pm}$ production asymmetry is measured in $pp$ collisions collected by the LHCb experiment at centre-of-mass energies of $sqrt{s} =7$ and 8 TeV. Promptly produced $D_s^{pm}$ mesons are used, which decay as $D_s^{pm}tophipi^{pm}$, with $phito K^+K^-$. The measurement is performed in bins of transverse momentum, $p_{rm T}$, and rapidity, $y$, covering the range $2.5<p_{rm T}<25.0$ GeV$/c$ and $2.0<y<4.5$. No kinematic dependence is observed. Evidence of nonzero $D_s^{pm}$ production asymmetry is found with a significance of 3.3 standard deviations.