The semileptonic decays of B/B s meson in the perturbative QCD approach: a short review

Abstract

In this short review, we present the current status about the theoretical and experimental studies for some important semileptonic decays of B/B s mesons. We firstly gave a brief introduction for the experimental measurements for B/B s → P (l + l − , l −ν l , νν) decays, the BaBar's R(D) and R(D * ) anomaly, the P ′ 5 deviation for B 0 → K * 0 µ + µ − decay. We then made a careful discussion about the evaluations for the relevant form factors in the light-cone QCD sum rule (LCSRs), the heavy quark effective theory, and the perturbative QCD factorization approach. By using the form factors calculated in the perturbative (pQCD) approach, we then calculate and show the pQCD predictions for the decay rates of many semileptonic decays of B/B s mesons. We also made careful phenomenological analysis for these pQCD predictions and found, in general, the following points: (a) For all the considered B/B s semileptonic decays, the next-to-leading order (NLO) pQCD predictions for their decay rates agree well with the data and those from other different theoretical methods; (b) For R(D) and R(D * ), the pQCD predictions agree very well with the data, the BaBar's anomaly of R(D ( * ) ) are therefore explained successfully in the standard model by employing the pQCD approach; and (c) We defined several new ratios R l,τ D and R l,τ Ds , they may be more sensitive to the QCD dynamics which controls the B/B s → (D ( * ) , D ( * ) s ) transitions than the old ratios, we therefore strongly suggest LHCb and the forthcoming Super-B experiments to measure these new ratios.

The B → D(*)lv decays in the pQCD approach with the Lattice QCD input

“…which has invoked intensive studies in the framework of the SM and/or various NP models, for example, in Refs. [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. As is well-known, the theoretical predictions for the ratios R(D) and R(D * ) have a direct strong dependence on the values and the shapes of the B → D ( * ) transition form factors F (+,0) (q 2 ), V (q 2 ) and A 0,1,2 (q 2 ).…”

Form factor ratios for Bs→Kℓν and BsMonahan1, Bouchard2, Lepage3 et al. 2018Phys. Rev. D251240View full textAdd to dashboardCite

“…Both jV ub j and jV cb j have been determined through measurements of multiple exclusive mesonic decay channels [1,2], primarily B → πlν l [3][4][5][6][7][8][9][10][11] and B → D ðÃÞ lν l respectively [12][13][14][15][16][17][18][19][20], although other channels are also used [21][22][23][24][25]. The B s → K decay has generally received less theoretical attention than the corresponding B decay, largely due to the absence of experimental data, although this channel has been studied on the lattice in [26,27], and using other theoretical approaches [28], including light cone sum rules [29,30], perturbative QCD [31,32] and QCD-inspired models [33][34][35][36][37]. Form factors for both B → πlν l and B → D ðÃÞ lν l decays have been calculated by several lattice groups [27,[38][39][40][41][42][43][44] and using light cone sum rules…”

B¯s0→(π0η(′),

“…As is well-known, the studies for the mixing and decays of B s meson play an important role in testing the standard model (SM) and in searching for the new physics beyond the SM [1,2]. Some B s meson decays, such as the leptonic decay B 0 s → µ + µ − and the hadronic decays B 0 s → (J/Ψφ, φφ, Kπ, KK, etc), have been measured recently by the LHCb, ATLAS and CMS collaborations [3][4][5].…”