CERN Accelerating science

LHCb Note
Report number	LHCb-CONF-2023-004 ; CERN-LHCb-CONF-2023-004
Title	Measurement of $CP$ asymmetry in $B^0_s \rightarrow D^{\mp}_s K^{\pm}$ decays
Corporate author(s)	The LHCb Collaboration
Collaboration	LHCb Collaboration
Submitted to	12th International Workshop on the CKM Unitarity Triangle (CKM 2023), Santiago De Compostela, Spain, 18 - 22 Sep 2023
Submitted by	lhcb.secretariat@cern.ch on 04 Oct 2023
Subject category	Particle Physics - Experiment
Accelerator/Facility, Experiment	CERN LHC ; LHCb
Free keywords	Flavour physics ; B physics ; CP violation ; CKM angle gamma
Abstract	A measurement of the $CP$-violating parameters in $B^0_s \rightarrow > D^{\mp}_s K^{\pm}$ decays obtained from $pp$ collisions is reported, using a data set corresponding to an integrated luminosity of $6\,\textrm{fb}^{-1}$ at a centre-of-mass energy of ${\sqrt{s}=13 \,\textrm{TeV}}$ recorded with the LHCb detector between 2015 and 2018. The measured values are: > \begin{align*} C_f &= \phantom{+}0.791 \pm 0.061 \pm 0.022 \, , \\ A_f^{\Delta \Gamma} &= -0.051 \pm 0.134 \pm 0.037\, , \\ A_{\bar{f}}^{\Delta \Gamma} &= -0.303 \pm 0.125 \pm 0.036\, , \\ S_f &= -0.571 \pm 0.084 \pm 0.023\, , \\ S_{\bar{f}} &= -0.503 \pm 0.084 \pm 0.025 \, , \end{align*} where the uncertainties are statistical and systematic, respectively. Together with the value of the $B_s^0$ mixing phase $-2 \beta{_s}$, these parameters are used to obtain a measurement of the CKM angle $\gamma$ from $B^0_s \rightarrow D^{\mp}_s K^{\pm}$ decays of $\gamma = ( 74\pm11)^{\circ}$ modulo $180^{\circ}$, where the uncertainty contains both statistical and systematic contributions.

Corresponding record in: Inspire
Email contact(s) : lhcb.secretariat@cern.ch ; jordy.butter@cern.ch