Search for CP violation in semileptonic Bs decays

TL;DR

This study searches for CP violation in Bs meson decays using proton-antiproton collision data, finding no evidence of new physics-induced CP violation within the experimental sensitivity.

Contribution

First search for CP violation in Bs -> Ds mu X decays at the Fermilab Tevatron, providing constraints on new physics contributions to Bs mixing.

Findings

Measured flavor-specific asymmetry a_fs^s consistent with zero

Excluded significant CP violation from new physics within sensitivity

Analyzed 5 fb^-1 of collision data

Abstract

We have performed a search for CP violation in a sample of Bs -> Ds mu X decays corresponding to $5$~fb$^{-1}$ of proton-antiproton collisions collected by the D0 detector in Run~II at the Fermilab Tevatron Collider. New physics in $B_s^0$ mixing could contribute a significant CP violating weak phase, which would be observed as a difference in the decay-time distribution for $B_s^0\to \bar{B}_s^0$ oscillated states versus that for $\bar{B}_s^0\to {B}_s^0$. A fit to the decay-time distributions of the $B_s^0/\bar{B}_s^0$ candidates yields the flavor-specific asymmetry $a_{fs}^{s}=[-1.7\pm 9.1\mathrm{(stat)}^{+1.4}_{-1.5}\mathrm{(syst)}] \times 10^{-3}$, which excludes CP violation due to new physics within the experimental sensitivity.