B→Stransition form factors in the perturbative QCD approach

Abstract

Under two different scenarios for the light scalar mesons, we investigate the transition form factors of B(B s ) mesons decay into a scalar meson in the perturbative QCD approach. In the large recoiling region, the form factors are dominated by the short-distance dynamics and can be calculated using perturbation theory. We adopt the dipole parametrization to recast the q 2 dependence of the form factors. Since the decay constants defined by the scalar current are large, our predictions on the B → S form factors are much larger than the B → P transitions, especially in the second scenario. Contributions from various light-cone distribution amplitudes (LCDAs) are elaborated and we find that the twist-3 LCDAs provide more than a half contributions to the form factors. The two terms of the twist-2 LCDAs give destructive contributions in the first scenario while they give constructive contributions in the second scenario. With the form factors, we also predict the decay width and branching ratios of the semileptonic B → Slν and B → Sl + l − decays. The branching ratios of B → Slν channels are found to have the order of 10 −4 while those of B → Sl + l − have the order of 10 −7 . These predictions can be tested by the future experiments.

Charmless weakBsdecays in the relativistic quark model

“…In Tables V-VII we compare our results for form factors of the weak B s decays to scalar K * 0 , axial vector K 1 and tensor K * 2 mesons at maximum recoil point q 2 = 0 with previous theoretical calculations [17,[22][23][24][25][26][27][28][29]. Predictions are mostly available for the weak B s decays to scalar K * 0 mesons.…”

“…In Table III we compare our predictions for the form factors of weak B s decays at maximum recoil q 2 = 0 with results of other calculations [13,[15][16][17][18][19][20][21]. Light-cone sum rules, including one-loop radiative corrections to twist-2 and twist-3 contributions, and leading order twist-4 corrections are used in Ref.…”

“…Perturbative QCD approach is applied in Refs. [16,17]. Calculations based on quark model and relativistic dispersion approach are given in Ref.…”

“…The matrix elements of the weak current for B s decays to the axial vector K 1 (1400) meson are obtained from Eqs. (24), (25) by the replacement of the set of form factors…”

$$B-S$$ B - S transition form-factors with the light-cone QCD sum rules

“…The B − S transition form-factors have been calculated with the LCSR [9][10][11][12], the three-point QCD sum rules [13][14][15], the perturbative QCD [16], the light front quark model [17], etc. In Refs.…”