# Measurement of CP violation in $B_s^0 \to \phi \phi$ decays

Abstract : A measurement of the decay time dependent $CP$-violating asymmetry in $B_s^0 \to \phi\phi$ decays is presented, along with measurements of the $T$-odd triple-product asymmetries. In this decay channel, the $CP$-violating weak phase arises from the interference between $B_s^0$-$\overline{B}_s^0$ mixing and the loop-induced decay amplitude. Using a sample of proton-proton collision data corresponding to an integrated luminosity of $3.0\, fb^{-1}$ collected with the LHCb detector, a signal yield of approximately 4000 $B_s^0 \to \phi\phi$ decays is obtained. The $CP$-violating phase is measured to be ${\phi_s =-0.17\pm0.15\mathrm{\,(stat)}\pm0.03\mathrm{\,(syst)}}$ rad. The triple-product asymmetries are measured to be ${A_U=-0.003\pm0.017\mathrm{\,(stat)}\pm0.006\mathrm{\,(syst)}}$ and ${A_V=-0.017\pm0.017\mathrm{\,(stat)}\pm0.006\mathrm{\,(syst)}}$. Results are consistent with the hypothesis of $CP$ conservation.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-01022651
Contributor : Sabine Starita <>
Submitted on : Thursday, July 10, 2014 - 3:52:02 PM
Last modification on : Wednesday, September 16, 2020 - 4:26:59 PM

### Citation

R. Aaij, Y. Amhis, S. Barsuk, M. Borsato, O. Callot, et al.. Measurement of CP violation in $B_s^0 \to \phi \phi$ decays. Physical Review D, American Physical Society, 2014, 90, pp.052011. ⟨10.1103/PhysRevD.90.052011⟩. ⟨in2p3-01022651⟩

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