Abstract
A measurement of the $B^0_s$ decay parameters in the $B^0_s \to J/\psi\phi$ channel using an integrated luminosity of 14.3 $\mathrm{fb}^{-1}$ collected by the ATLAS detector from 8 TeV $pp$ collisions at the LHC is presented. The measured parameters include the $CP$-violating phase $\phi_s$, the decay width $\Gamma_s$ and the width difference between the mass eigenstates $\Delta\Gamma_s$. The values measured for the physical parameters are statistically combined with those from 4.9 $\mathrm{fb}^{-1}$ of 7 TeV data, leading to the following: \begin{eqnarray*} \phi_s & = & -0.090 \pm 0.078\;\mathrm{(stat.)} \pm 0.041\;\mathrm{(syst.)\;rad} \\ \Delta\Gamma_s & = & 0.085 \pm 0.011\;\mathrm{(stat.)} \pm 0.007\;\mathrm{(syst.)\;ps}^{-1} \\ \Gamma_s & = & 0.675 \pm 0.003\;\mathrm{(stat.)} \pm 0.003\;\mathrm{(syst.)\;ps}^{-1}. \end{eqnarray*} In the analysis the parameter $\Delta\Gamma_s$ is constrained to be positive. Results for $\phi_s$ and $\Delta\Gamma_s$ are also presented as 68% and 95% likelihood contours in the $\phi_s-\Delta\Gamma_s$ plane. Also measured in this decay channel are the transversity amplitudes and corresponding strong phases. All measurements are in agreement with the Standard Model predictions.
Original language | English |
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Journal | Journal of High Energy Physics |
Volume | 147 |
Early online date | 24 Aug 2016 |
DOIs | |
Publication status | E-pub ahead of print - 24 Aug 2016 |
Bibliographical note
27 pages plus author list (44 pages total), 10 figures, 8 tables, published version, all figures and tables are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/BPHY-2014-03/Keywords
- hep-ex
- B physics
- Hadron-Hadron scattering (experiments)
- CP violation
- Flavor physics