Stringent tests of constrained Minimal Flavor Violation through Delta F=2 transitions

作者：Buras Andrzej J^*; Girrbach Jennifer

来源：European Physical Journal C, 2013, 73(9): 2560.

DOI：10.1140/epjc/s10052-013-2560-1

New Physics contributions to Delta F = 2 transitions in the simplest extensions of the Standard Model (SM), the models with constrained Minimal Flavor Violation (CMFV), are parametrized by a single variable S(v), the value of the real box diagram function that in CMFV is bounded from below by its SM value S-0(x(t)). With already very precise experimental values of epsilon(K), Delta M-d, Delta M-s and precise values of the CP-asymmetry S-psi KS and of (B) over cap (K) entering the evaluation of epsilon(K), the future of CMFV in the Delta F = 2 sector depends crucially on the values of vertical bar V-cb vertical bar, vertical bar V-ub vertical bar, F-Bs root(B) over cap (Bs) and F-Bd root(B) over cap (Bd). The ratio xi of the latter two non-perturbative parameters, already rather precisely determined from lattice calculations, allows then together with Delta M-s/Delta M-d and S psi(KS) to determine the range of the angle gamma in the unitarity triangle independently of the value of S(v). Imposing in addition the constraints from vertical bar epsilon(K)vertical bar and Delta M-d allows to determine the favorite CMFV values of vertical bar V-cb vertical bar, vertical bar V-ub vertical bar, F-Bs root(B) over cap (Bs) and F-Bd root(B) over cap (Bd) as functions of S(v) and gamma. The vertical bar V-cb vertical bar(4) dependence of epsilon(K) allows to determine vertical bar V-cb vertical bar for a given S(v) and gamma with a higher precision than it is presently possible using tree- level decays. The same applies to vertical bar V-ub vertical bar, vertical bar V-td vertical bar and vertical bar V-ts vertical bar that are automatically determined as functions of S(v) and gamma. We derive correlations between F-Bs root(B) over cap (Bs) and F-Bd root(B) over cap (Bd), vertical bar V-cb vertical bar, vertical bar V-ub vertical bar and gamma that should be tested in the coming years. Typically F-Bs root(B) over cap (Bs) and F-Bd root(B) over cap (Bd) have to be lower than their present lattice values, while vertical bar V-cb vertical bar has to be higher than its tree-level determination, with a significance depending on the evolution of their errors. Within the SM this would imply values for B(K+ -> pi(+) nu(nu) over bar) and B(KL -> pi(0)nu(nu) over bar) that are typically larger by (15-20) % than those presently quoted in the literature. The region in the space of these three parameters allowed by CMFV indicates tensions in this class of models and hints for the presence of new sources of flavor violation and/or new local operators in Delta F = 2 data that are strongly suppressed in these models. As a byproduct we propose to reduce the present uncertainty in the charm contribution to epsilon(K) by using the experimental value of Delta M-K.

• 出版日期2013-9-6