Abstract

A flavor-tagged time-dependent angular analysis of the decay $B_s^{0}\rightarrow\phi\phi$ is performed using $pp$ collision data collected by the LHCb experiment at $\sqrt{s}=13$ TeV, the center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6 fb^{-1}. The $\it{CP}$-violating phase and direct $\it{CP}$-violation parameter are measured to be $\phi_{s\bar{s}s} = -0.042 \pm 0.075 \pm 0.009 $ rad and $|\lambda|=1.004\pm 0.030 \pm 0.009 $, respectively, assuming the same values for all polarization states of the $\phi\phi$ system. In these results, the first uncertainties are statistical and the second systematic. These parameters are also determined separately for each polarization state, showing no evidence for polarization dependence. The results are combined with previous LHCb measurements using $pp$ collisions at center-of-mass energies of 7 and 8 TeV, yielding $\phi_{s\bar{s}s} = -0.074 \pm 0.069 $ rad and $|\lambda|=1.009 \pm 0.030$. This is the most precise study of time-dependent $\it{CP} $ violation in a penguin-dominated $B$ meson decay. The results are consistent with $\it{CP} $ symmetry and with the Standard Model predictions.

Figures and captions

\textcolor{black}{(a) Mass distribution of the $ B ^0_ s \rightarrow \phi\phi$ candidates, superimposed by the fit projections.} (b-d) Background-subtracted distributions of angular variables ($\cos\theta_{1}$ and $\chi$) and decay time, superimposed by the fit projections.	Fig1a.pdf [27 KiB] HiDef png [251 KiB] Thumbnail [208 KiB] *.C file
	Fig1b.pdf [16 KiB] HiDef png [128 KiB] Thumbnail [118 KiB] *.C file
	Fig1c.pdf [15 KiB] HiDef png [128 KiB] Thumbnail [117 KiB] *.C file
	Fig1d.pdf [22 KiB] HiDef png [167 KiB] Thumbnail [155 KiB] *.C file
Comparison of $\phi_{ s }^{ s \overline s s }$ measurements from this and previous analyses [16,17,18] by the LHCb collaboration. The vertical band indicates the SM prediction [6,7,9].	Fig2.pdf [13 KiB] HiDef png [78 KiB] Thumbnail [69 KiB] *.C file
Animated gif made out of all figures.	PAPER-2023-001.gif Thumbnail

Tables and captions

Measured observables in the polarization-independent fit. The first uncertainties are statistical and the second systematic.	Table_1.pdf [67 KiB] HiDef png [94 KiB] Thumbnail [44 KiB] tex code
Systematic uncertainties for physics parameters in the polarization-independent fit, the values are given in units of $10^{-3}$ ($10^{-3}$ rad for angles).	Table_2.pdf [71 KiB] HiDef png [75 KiB] Thumbnail [34 KiB] tex code

Created on 27 April 2024.