Time-dependent angular analysis of the decay B<sup>0</sup><sub>s</sub> → J/ψφ and extraction of ΔΓ<sub>s</sub> and the CP-violating weak phase φ<sub>s</sub> by ATLAS
A measurement of B<sup>0</sup><sub>s</sub> → J/ψϕ decay parameters, including the CP-violating weak phase ϕ<sub>s</sub> and the decay width difference ΔΓ<sub>s</sub> is reported, using 4.9 fb<sub>−1</sub> of integrated luminosity collected...
Guardado en:
| Autores principales: | , , , , , |
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| Formato: | Articulo |
| Lenguaje: | Español |
| Publicado: |
2012
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| Materias: | |
| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/81238 |
| Aporte de: |
| Sumario: | A measurement of B<sup>0</sup><sub>s</sub> → J/ψϕ decay parameters, including the CP-violating weak phase ϕ<sub>s</sub> and the decay width difference ΔΓ<sub>s</sub> is reported, using 4.9 fb<sub>−1</sub> of integrated luminosity collected in 2011 by the ATLAS detector from LHC pp collisions at a centre-of-mass energy √s = 7 TeV. The mean decay width Γ<sub>s</sub> and the transversity amplitudes |A<sub>0</sub>(0)|<sup>2</sup> and |A<sub>∥</sub>(0)|<sup>2</sup> are also measured. The values reported for these parameters are:
ϕ<sub>s</sub> = 0.22 ± 0.41 (stat.) ± 0.10 (syst.) rad
ΔΓ<sub>s</sub> = 0.053 ± 0.021 (stat.) ± 0.010 (syst.) ps<sup>−1</sup>
Γ<sub>s</sub> = 0.677 ± 0.007 (stat.) ± 0.004 (syst.) ps<sup>−1</sup>
|A<sub>0</sub>(0)|<sup>2</sup> = 0.528 ± 0.006 (stat.) ± 0.009 (syst.)
|A<sub>∥</sub>(0)|<sup>2</sup> = 0.220 ± 0.008 (stat.) ± 0.007 (syst.)
where the values quoted for ϕ<sub>s</sub> and ΔΓ<sub>s</sub> correspond to the solution compatible with the external measurements to which the strong phase δ⊥ is constrained and where ΔΓ<sub>s</sub> is constrained to be positive. The fraction of S-wave KK or f<sub>0</sub> contamination through the decays Bsup>0</sup><sub>s</sub> → J/ψK+K− (f<sub>0</sub>) is measured as well and is found to be consistent with zero. Results for ϕ<sub>s</sub> and ΔΓ<sub>s</sub> are also presented as 68%, 90% and 95% likelihood contours, which show agreement with Standard Model expectations. |
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