2015/11/30 by Artuso, Marina, Borissov, Guennadi, Lenz, Alexander
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Phenomenology (hep-ph)
paper · doi:10.48550/arxiv.1511.09466
We review experimental and theoretical aspects of CP violation in the Bs0-system. In that respect we present updates for the mixing parameters of the Bs0 mesons expected in the Standard Model (SM): the mass difference ΔMs\rm SM = (18.3 ± 2.7) ps-1, the decay rate difference ΔΓs\rm SM = (0.085 ± 0.015) ps-1, the flavour specific CP asymmetry a\rm fss, \rm SM = (2.22 ± 0.27) ⋅ 10-5 and the equivalent quantities in the B0-sector. The experimental measurements of ΔMs and ΔΓs are more precise and agree very well with theoretica predictions, which can also be viewed as a proof of theoretical tools, like the Heavy Quark Expansion (HQE). CP violating studies in the Bs0 system provide essential information to test the SM expectations. Mixing quantities can be used to study model independent bounds on new physics (NP) effects, yielding the familiar picture: the standard model (SM) gives the dominant contribution, while there is still some sizable space for NP effects. In the case of ΔMs effects of the order of 15% are not excluded. In the CP phase ϕs due to CP violation in the interference of decays and mixing \cal O (100 %) effects are still possible. The semi-leptonic CP asymmetry a\rm sls, which is due to CP violation in mixing, could still be a factor of 250 larger than its robust SM expectation and thus provides a very clean observable for NP searches. We comment in detail on theoretical improvements that are necessary to make full use of the experimental precision.