CMS-PAS-BPH-13-012

CMS-PAS-BPH-13-012
Measurement of the CP-violating weak phase $\phi_\mathrm{s}$ and the decay width difference $\Delta\Gamma_\mathrm{s}$ using the $\mathrm{B_s} \to \mathrm{J}/\psi \phi(1020)$ decay channel
CMS Collaboration
2014

Abstract: The CP-violating weak phase $\phi_\mathrm{s}$ and the decay width difference $\Delta\Gamma_\mathrm{s}$ of $\mathrm{B_s}$ mesons are measured by the CMS experiment at the LHC using a data sample of ${\mathrm{B_s} \to \mathrm{J}/\psi(\mu^+ \mu^-)\phi(\mathrm{K^+K^-})}$ decays. The analysed dataset corresponds to an integrated luminosity of about 20 fb $^{-1}$ collected in pp collisions at a centre-of-mass energy $\sqrt{s}=$ 88 TeV. A total of 49,000 reconstructed $\mathrm{B_s}$ decays are used to extract the values $\phi_\mathrm{s}$ and $\Delta\Gamma_\mathrm{s}$ by performing a time-dependent and flavour-tagged angular analysis of the $\mu^+ \mu^- \mathrm{K^+K^-}$ final state. The weak phase is measured to be $\phi_\mathrm{s} =$ -0.03 $\pm$ 0.11 (stat.) $\pm$ 0.03 (syst.) rad, and the decay width difference between the $\mathrm{B_s}$ mass eigenstates is $\Delta\Gamma_\mathrm{s} =$ 0.096 $\pm$ 0.014 (stat.) $\pm$ 0.007 (syst.) ps $^{-1}$ .
Links: CDS record (PDF) ; inSPIRE record ; Public twiki page ; CADI line (restricted) ; These preliminary results are superseded in this paper, PLB 757 (2016) 97. The superseded preliminary plots can be found here.

CMS Publications