Precision Measurement of the $B_s-\kern0.18em\overline{\kern -0.18em B}{}^0_s$ Oscillation Frequency $\Delta m_s$ with $B_s\to D_s^-\pi^+$ Decays at LHCb

TL;DR

This paper reports a highly precise measurement of the $B_s$ meson oscillation frequency $m_s$ using $B_s o D_s^- \u03c0^+$ decays at LHCb, refining our understanding of quark mixing and CP violation.

Contribution

It presents a new, more precise measurement of $m_s$ using 6 fb$^{-1}$ of data at 13 TeV, improving the accuracy of CKM matrix constraints.

Findings

Measured $m_s = 17.7683 b1 0.0051( ext{stat.}) b1 0.0032( ext{syst.})$ ps$^{-1}$

Combined with previous data, $m_s^ ext{LHCb} = 17.7656 b1 0.0057$ ps$^{-1}$

Enhanced precision in quark mixing parameters

Abstract

Decays of $B^0_s \to D_s^- \pi^+$ allow to determine the oscillation frequency $\Delta m_s$ between the $B^0_s$ particle and $\kern0.18em\overline{\kern -0.18em B}{}^0_s$ antiparticle states with high precision. It is a crucial input to constrain the CKM matrix and a manifestation of the quantum nature of physics. A new measurement of this frequency is presented, using a dataset corresponding to $6\,\mathrm{fb}^{-1}$ of $pp$ collisions, recorded by LHCb at a centre-of-mass energy of $13\,\mathrm{TeV}$. The oscillation frequency is determined to be $\Delta m_s = 17.7683\pm0.0051(\mathrm{stat.})\pm0.0032(\mathrm{syst.})\,\mathrm{ps}^{-1}$ and a combination with previous LHCb measurements yields $\Delta m_s^\mathrm{LHCb} = 17.7656\pm0.0057\,\mathrm{ps}^{-1}$.