CP violation and limits on New Physics including recent $B_s$ measurements

Abstract

We analyse present constraints on the SM parameter space and derive, in a model independent way, various bounds on New Physics contributions to $B_d^0$--$\bar B_d^0$ and $B_s^0$--$\bar B_s^0$ mixings. Our analyses include information on a large set of asymmetries, leading to the measurement of the CKM phases $γ$ and $\barβ$, as well as recent data from D0 and CDF related to the $B_s^0$--$\bar B_s^0$ system such as the measurement of $ΔM_{B_s}$, $A_{SL}$ and $ΔΓ_{s}^{CP}$. We examine in detail several observables such as the asymmetries $A_{sl}^d$, $A_{SL}$, the width differences $ΔΓ_{d}$ and $ΔΓ_{s}^{CP}$ and discuss the rôle they play in establishing the limits on New Physics. The present data clearly favour the SM, with the New Physics favoured region placed around the SM solution. A New Physics solution significantly different from the SM is still allowed, albeit quite disfavoured (2.6% probability). We analyse the presently available indirect knowledge on the phase $\barχ$ entering in $B_s^0$--$\bar B_s^0$ mixing and study the impact of a future measurement of $\barχ$ to be achieved at LHC, through the measurement of the time-dependent CP asymmetry in $B_s\to J/ΨΦ$ decays.

29 pages, 31 figures; updated analyses and references