Time Dependent $B_s^0 - \bar{B_s^0}$ Oscillations Using Exclusively Reconstructed $D_s^+$ Decays at SLD

TL;DR

This paper reports a preliminary exclusion of certain oscillation frequencies of $B_s^0$ mesons using reconstructed decays from the SLD experiment, providing constraints on $B_s^0 - ar{B_s^0}$ mixing.

Contribution

It introduces a novel method of partially reconstructing $B_s^0$ mesons via $D_s$ decays and uses polarized $Z^0$ decays to determine flavor at production.

Findings

Excluded $ riangle m_s$ ranges at 95% CL

Reconstructed 361 candidate events

Set limits on $B_s^0$ oscillation frequency

Abstract

We set a preliminary 95% C.L. exclusion on the oscillation frequency of $B_s^0 - \bar{B_s^0}$ mixing using a sample of 400,000 hadronic $Z^0$ decays collected by the SLD experiment at the SLC during the 1996-98 run. In this analysis, $B_s^0$ mesons are partially reconstructed by combining a fully reconstructed $D_s$ with other $B_s^0$ decay tracks. The $D_s$ decays are reconstructed via the $\phi \pi$ and $K^* K$ channels. The $b$-hadron flavor at production is determined by exploiting the large forward-backward asymmetry of polarized $Z^0 \to b \bar{b}$ decays as well as information from the hemisphere opposite to the reconstructed B decay. The flavor of the $B_s^0$ at the decay vertex is determined by the charge of the $D_s$. A total of 361 candidates passed the final event selection cuts. This analysis excludes the following values of the $B_s^0 - \bar{B_s^0}$ mixing oscillation frequency: $\Delta m_s < 1.5$ ps$^{-1}$, $2.6 < \Delta m_s < 4.9$ ps$^{-1}$, and $10.8 < \Delta m_s < 13.5$ ps$^{-1}$ at the 95% confidence level.