Measurement of the semileptonic charge asymmetry using Bs^0 -> D_s mu X decays

TL;DR

This paper reports a precise measurement of the flavor-specific semileptonic charge asymmetry in Bs meson decays, using proton-antiproton collision data, which aligns with the Standard Model predictions.

Contribution

The study provides the most precise measurement of the Bs meson charge asymmetry using 10.4 fb^-1 of data from the D0 detector, improving previous experimental constraints.

Findings

Measured asymmetry a^s_ls = [-1.12 ± 0.74 (stat) ± 0.17 (syst)]%

Result is consistent with Standard Model predictions

Achieved highest precision in this measurement to date

Abstract

We present a measurement of the time-integrated flavor-specific semileptonic charge asymmetry in the decays of Bs mesons that have undergone flavor mixing, a^s_ls, using B_s^0 (barB_s^0) -> D_s^-/+ mu^+/- X decays, with D_s^-/+ -> phi pi^-/+ and phi K^+ K^-, using 10.4 fb^-1 of proton-antiproton collisions collected by the D0 detector during Run II at the Fermilab Tevatron Collider. A fit to the difference between the time-integrated D_s^-$ and D_s^+ mass distributions of the B_s^0 and barB^0_s candidates yields the flavor-specific asymmetry a^s_ls = [-1.12 pm 0.74 (stat) +/-0.17 (syst)]% which is the most precise measurement and in agreement with the standard model prediction.