Abstract

The decay-time-dependent $CP$ asymmetry in $B^0_s\to J/\psi(\to \mu^{+}\mu^{-}) K^{+}K^{-}$ decays is measured using proton-proton collision data, corresponding to an integrated luminosity of 6 $fb^{-1}$, collected with the LHCb detector at a center-of-mass energy of 13 TeV. Using a sample of approximately 349 000 $B^{0}_{s}$ signal decays with an invariant $K^{+}K^{-}$ mass in the vicinity of the $\phi(1020)$ resonance, the $CP$-violating phase $\phi_s$ is measured, along with the difference in decay widths of the light and heavy mass eigenstates of the $B^0_s$-$\bar{B}^0_s$ system, $\Delta\Gamma_s$, and the difference of the average $B^0_s$ and $B^0$ meson decay widths, $\Gamma_s-\Gamma_d$. The values obtained are $\phi_s = \ -0.039 \pm 0.022 \pm 0.006$ rad, $\Delta\Gamma_s = 0.0845 \pm 0.0044 \pm 0.0024 $ ps$^{-1}$ and $\Gamma_s-\Gamma_d = -0.0056 ^{+ 0.0013}_{-0.0015} \pm 0.0014$ ps$^{-1}$, where the first uncertainty is statistical and the second systematic. These are the most precise single measurements to date and are consistent with expectations based on the Standard Model and with the previous LHCb analyses of this decay. These results are combined with previous independent LHCb measurements. The phase $\phi_s$ is also measured independently for each polarization state of the $K^{+}K^{-}$ system and shows no evidence for polarization dependence.

Figures and captions

Distribution of $m( { J \mskip -3mu/\mskip -2mu\psi } K ^+ K ^- )$ for the full data sample and projection of the maximum likelihood fit.	Fig1.pdf [23 KiB] HiDef png [257 KiB] Thumbnail [221 KiB] *.C file
Decay-time and decay-angle distributions for background-subtracted $B_s^0\rightarrow { J \mskip -3mu/\mskip -2mu\psi } K ^+ K ^- $ decays with the one-dimensional projections of the PDF at the maximum-likelihood point. The data and fit projections for the different samples considered [data-taking year, trigger and tagging categories, $m( K ^+ K ^- )$ bins] are combined.	Fig2a.pdf [19 KiB] HiDef png [256 KiB] Thumbnail [207 KiB] *.C file
	Fig2b.pdf [20 KiB] HiDef png [223 KiB] Thumbnail [170 KiB] *.C file
	Fig2c.pdf [20 KiB] HiDef png [237 KiB] Thumbnail [188 KiB] *.C file
	Fig2d.pdf [22 KiB] HiDef png [227 KiB] Thumbnail [179 KiB] *.C file
Animated gif made out of all figures.	PAPER-2023-016.gif Thumbnail

Tables and captions

Main physics parameters of interest, where the first uncertainty is statistical and the second systematic.	Table_1.pdf [67 KiB] HiDef png [117 KiB] Thumbnail [54 KiB] tex code
Measured observables in the polarization-dependent fit. The uncertainties are statistical only.	Table_2.pdf [68 KiB] HiDef png [160 KiB] Thumbnail [67 KiB] tex code

Supplementary Material [file]

Supplementary material full pdf	supple[..].pdf [424 KiB]
This ZIP file contains supplemetary material for the publication LHCb-PAPER-2023-016. The files are: Supplementary.pdf : An overview of the extra figures and tables *.pdf, *.png, *.eps : The figures in variuous formats	Fig1_S.pdf [16 KiB] HiDef png [190 KiB] Thumbnail [169 KiB] *C file
	Fig2_S.pdf [14 KiB] HiDef png [121 KiB] Thumbnail [97 KiB] *C file
	Fig3_S.pdf [15 KiB] HiDef png [118 KiB] Thumbnail [101 KiB] *C file
	Fig4_S.pdf [58 KiB] HiDef png [308 KiB] Thumbnail [159 KiB] *C file

Created on 27 April 2024.