Effective lifetimes of B s decays and their constraints on the Bs0-bar{B}s0 mixing parameters

European Physical Journal C (Impact Factor: 5.44). 09/2011; 71. DOI: 10.1140/epjc/s10052-011-1789-9

ABSTRACT Measurements of the effective lifetimes of B s -meson decays, which only require untagged rate analyses, allow us to probe the width difference Delta Gamma s and the CP-violating phase varphi s of B0s-bar{B}0s mixing. We point out that the dependence of the effective lifetime on non-linear terms in Delta Gamma s allows for a determination of varphi s and Delta Gamma s given a pair of B s decays into CP-even and CP-odd final states. Using recent lifetime measurements of B0sto K+K- and B0sto J/psi f0(980) decays, we illustrate this method and show how it complements the constraints in the varphi s -Delta Gamma s plane from other observables.

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    ABSTRACT: Neutral mesons exhibit a phenomenon called flavour mixing. As a consequence of a second order weak process the flavour eigenstates corresponding to the meson and its anti-meson are superpositions of two mass eigenstates. A meson produced in a flavour state changes into an anti-meson and back again as a function of time. Such flavour oscillations are considered sensitive probes of physics beyond the Standard Model. In this brief review I summarize the status of experimental constraints on mixing parameters in the meson system.
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    ABSTRACT: The three-body charmless hadronic decay $B^0_s \rightarrow K^{0}_{\rm S} \pi^{+}\pi^{-}$ provides a number of novel possibilities to search for CP violation effects and test the Standard Model of particle physics. These include fits to the Dalitz-plot distributions of the decay-time-integrated final state, decay-time-dependent (but without initial state flavour tagging) fits to the Dalitz-plot distribution, as well as full decay-time-dependent and flavour tagged fits. The relative sensitivities of these different approaches are investigated.
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    ABSTRACT: Measurements of the Bs0-B¯s0 mixing phase ϕs appear to be converging towards the SM prediction, suggesting that contributions from New Physics (NP), if present, are small. This poses the question of whether smallish NP in ϕs can be distinguished from the hadronic uncertainties present in the interfering Bs decay mode. In this paper we discuss the potential of extracting ϕs from the decay modes Bs→J/ψη and Bs→J/ψf0(980) and how their respective hadronic uncertainties can be controlled. In addition, we demonstrate how the branching ratios of the former decays can be used to estimate the η--η' mixing angles. Finally, we point out that effective lifetime measurements of decay modes such as the Bs→J/ψf0(980) can be used to constrain both ϕs and the Bs decay width difference ΔΓs, complementary to the usual time-dependent tagged analysis.
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