Accurate decay-constant ratios fBfB and fBsfBs from Borel QCD sum rules

作者：Lucha Wolfgang^*; Melikhov Dmitri; Simula Silvano

来源：PHYSICAL REVIEW D, 2015, 91(11): 116009.

DOI：10.1103/PhysRevD.91.116009

We present our analysis of the decay constants of the beauty vector mesons B* and B-s* within the framework of dispersive sum rules for the two-point correlator of vector currents in QCD. While the decay constants of the vector mesons f(B*) and f(Bs*)-similar to the decay constants of the pseudoscalar mesons f(B) and f(Bs)-individually have large uncertainties induced by theory parameters not known with a satisfactory precision, these uncertainties almost entirely cancel out in the ratios of vector over pseudoscalar decay constants. These ratios, thus, may be predicted with very high accuracy due to the good control over the systematic uncertainties of the decay constants gained upon application of our hadron- parameter extraction algorithm. Our final results read f(B*)/f(B) = 0.944 +/- 0.011(OPE) +/- 0.018(syst) and f(Bs*)/f(Bs) = 0.947 +/- 0.023(OPE) +/- 0.020(syst). Thus, both f(B*)/f(B) and f(Bs*)/f(Bs) are less than unity at 2.5 sigma and 2 sigma level, respectively.

• 出版日期2015-6-23