What if the Mass Difference $\Delta M_s$ is around 18 Inverse Picoseconds?

Abstract

Present experiments in pursuit of the mass difference in the Bs-Bs(bar) system have put a lower bound on this quantity of $\Delta M_s>14.9p{s}^{-1}$ (at 95% C.L.). The same experiments also yield a local minimum in the log-likelihood function around $\Delta M_s=17.7p{s}^{-1}$, which is $2.5\sigma$ away from being zero. Motivated by these observations, we investigate the consequences of a possible measurement of $\Delta M_s=17.7\pm 1.4p{s}^{-1}$, in the context of both the standard model and supersymmetric models with minimal flavor violation. We perform a fit of the quark mixing parameters in these theories and estimate the expected ranges of the CP asymmetries in B decays, characterized by $\alpha$, $\beta$ and $\gamma$, the interior angles of the CKM-unitarity triangle. Based on this study, we argue that, if indeed $\Delta M_s$ turns out to be in its currently-favored range, this would disfavor a large class of supersymmetric models. Indeed, of all the models examined here, the best fit to the data occurs for the standard model.

Comments: 14 pages, LaTeX, 8 figures, corrected some typos. Accepted for publication in Eur. Phys. J. C