Precision measurement of the $B^{0}_{s}$-$\bar{B}^{0}_{s}$ oscillation frequency with the decay $B^{0}_{s}\rightarrowD^{-}_{s}\pi^{+}$

TL;DR

This paper reports the most precise measurement to date of the $B^{0}_{s}$-$ar{B}^{0}_{s}$ oscillation frequency, using a large dataset from the LHCb experiment, crucial for testing the Standard Model and exploring new physics.

Contribution

The paper provides the first measurement of $ riangle m_s$ with unprecedented precision using 1.0 fb$^{-1}$ of data from LHCb, significantly improving previous results.

Findings

Measured $ riangle m_s$ as 17.768 $ ext{ps}^{-1}$ with high precision.

Reconstructed about 34,000 $B^{0}_{s} ightarrow D_{s}^{-}\pi^{+}$ decays.

Achieved an average decay time resolution of 44 fs.

Abstract

A key ingredient to searches for physics beyond the Standard Model in $B^{0}_{s}$ mixing phenomena is the measurement of the $B^{0}_{s}$-$\bar{B}^{0}_{s}$ oscillation frequency, which is equivalent to the mass difference $\Delta m_{s}$ of the $B^{0}_{s}$ mass eigenstates. Using the world's largest $B^{0}_{s}$ meson sample accumulated in a dataset, corresponding to an integrated luminosity of 1.0 fb$^{-1}$, collected by the LHCb experiment at the CERN LHC in 2011, a measurement of $\Delta m_{s}$ is presented. A total of about 34,000 $B^{0}_{s}\rightarrowD^{-}_{s}\pi^{+}$ signal decays are reconstructed, with an average decay time resolution of 44 fs. The oscillation frequency is measured to be \mbox{$\Delta m_{s}$ = 17.768 $\pm$ 0.023 (stat) $\pm$ 0.006 (syst) ps$^{-1}$}, which is the most precise measurement to date.