First measurement of the CP-violating phase in $B_s^0 \to φφ$ decays

The LHCb Collaboration, Matthew Needham, Franz Muheim, Peter Clarke, Yuehong Xie, Stephan Eisenhardt

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

A first flavour-tagged measurement of the time-dependent CP-violating asymmetry in $B_s^0 \to \phi\phi$ decays is presented. In this decay channel, the CP-violating weak phase arises due to CP violation in the interference between $B_s^0$-$\bar{B}_s^0$ mixing and the $b \to s \bar{s} s $ gluonic penguin decay amplitude. Using a sample of $pp$ collision data corresponding to an integrated luminosity of $1.0\; fb^{-1}$ and collected at a centre-of-mass energy of $7 \rm TeV$ with the LHCb detector, $880\ \B_s^0 \to \phi\phi$ signal decays are obtained. The CP-violating phase is measured to be in the interval [-2.46, -0.76] \rm rad$ at 68% confidence level. The p-value of the Standard Model prediction is 16%.
Original languageEnglish
JournalPhysical Review Letters
Early online date28 Mar 2013
Publication statusPublished - 2013


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