Effective Lifetimes of $B_s$ Decays and their Constraints on the $B_s^0$-$\bar B_s^0$ Mixing Parameters

09/2011; DOI: 10.1140/epjc/s10052-011-1832-x
Source: arXiv

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 $\phi_s$ of $B^0_s$-$\bar B^0_s$
mixing. We point out that the dependence of the effective lifetime on
non-linear terms in $\Delta\Gamma_s$ allows for a determination of $\phi_s$ and
$\Delta\Gamma_s$ given a pair of $B_s$ decays into CP-even and CP-odd final
states. Using recent lifetime measurements of $B^0_s\to K^+K^-$ and $B^0_s\to
J/\psi f_0(980)$ decays, we illustrate this method and show how it complements
the constraints in the $\phi_s$-$\Delta\Gamma_s$ plane from other observables.

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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.
    Nuclear Physics B - Proceedings Supplements 08/2013; · 0.88 Impact Factor


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