Eur. Phys. J. C 18, 665-672
DOI: 10.1007/s100520100582

What if the mass difference is around 18 inverse picoseconds?

A. Ali¹ and D. London<sup>2

1</sup>  Deutsches Elektronen Synchrotron DESY, 22603 Hamburg, Germany
²  Laboratoire René J.-A. Lévesque, Université de Montréal, C.P. 6128, succ. centre-ville, Montréal, QC, H3C 3J7 Canada

(Received: 14 December 2000 / Published online: 23 January 2001 -© Springer-Verlag 2001)

Abstract
Present experiments in pursuit of the mass difference in the B_s⁰- system have put a lower bound on this quantity of (at 95% C.L.). The same experiments also yield a local minimum in the log-likelihood function around , which is away from being zero. Motivated by these observations, we investigate the consequences of a possible measurement of , 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 , and , the interior angles of the CKM-unitarity triangle. Based on this study, we argue that, if indeed 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.

© Società Italiana di Fisica, Springer-Verlag 2001