The recent measurements of the B-s(0) meson mixing amplitude by CDF and of the leptonic branching fraction BR(B ->tau nu(tau)) by Belle call for an upgraded analysis of the Unitarity Triangle in the Standard Model. Besides improving the previous constraints on the parameters of the CKM matrix, these new measurements, combined with the recent determinations of the angles alpha, beta and gamma from non-leptonic decays, allow, in the Standard Model, a quite accurate extraction of the values of the hadronic matrix elements relevant for K-0-(K) over bar (0) and B-s,d(0)-(B) over bar (0)(s,d) mixing and of the leptonic decay constant f(B). In this paper we upgrade the UT fit, we determine from the data the kaon B-parameter (B) over cap (K), the B-0 mixing amplitude parameters f(Bs)(B) over cap (1/2)(Bs) and xi, the decay constant f(B), and make a comparison of the obtained values with lattice predictions. We also discuss the different determinations of V-ub and show that current data do not favour the value measured in inclusive decays.
Bona, M., Ciuchini, M., Franco, E., Lubicz, V., Martinelli, G., Parodi, F., et al. (2006). The unitarity triangle fit in the Standard Model and hadronic parameters from lattice QCD: a reappraisal after the measurements of Delta_ms and BR(B -> tau nu_tau). JOURNAL OF HIGH ENERGY PHYSICS, 10, 081.
The unitarity triangle fit in the Standard Model and hadronic parameters from lattice QCD: a reappraisal after the measurements of Delta_ms and BR(B -> tau nu_tau)
LUBICZ, Vittorio;
2006-01-01
Abstract
The recent measurements of the B-s(0) meson mixing amplitude by CDF and of the leptonic branching fraction BR(B ->tau nu(tau)) by Belle call for an upgraded analysis of the Unitarity Triangle in the Standard Model. Besides improving the previous constraints on the parameters of the CKM matrix, these new measurements, combined with the recent determinations of the angles alpha, beta and gamma from non-leptonic decays, allow, in the Standard Model, a quite accurate extraction of the values of the hadronic matrix elements relevant for K-0-(K) over bar (0) and B-s,d(0)-(B) over bar (0)(s,d) mixing and of the leptonic decay constant f(B). In this paper we upgrade the UT fit, we determine from the data the kaon B-parameter (B) over cap (K), the B-0 mixing amplitude parameters f(Bs)(B) over cap (1/2)(Bs) and xi, the decay constant f(B), and make a comparison of the obtained values with lattice predictions. We also discuss the different determinations of V-ub and show that current data do not favour the value measured in inclusive decays.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.