The semileptonic decays of B/BsB/B_s meson in the perturbative QCD approach: A short review

Jan 2, 2014
12 pages
Published in:
  • Chin.Sci.Bull. 59 (2014) 3787-3800
e-Print:

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Abstract: (arXiv)
In this short review, we present the current status about the theoretical and experimental studies for some important semileptonic decays of B/BsB/B_s mesons. We firstly gave a brief introduction for the experimental measurements for B/BsP(l+l,lνˉl,ννˉ)B/B_s \to P (l^+l^-, l^-\bar{\nu}_l, \nu \bar{\nu}) decays, the BaBar's R(D)R(D) and R(D)R(D^*) anomaly, the P5P_5^\prime deviation for B0K0μ+μB^0 \to K^{*0} \mu^+ \mu^- 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/BsB/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/BsB/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)R(D) and R(D)R(D^*), the pQCD predictions agree very well with the data, the BaBar's anomaly of R(D())R(D^{(*)}) are therefore explained successfully in the standard model by employing the pQCD approach; and (c) We defined several new ratios RDl,τR_D^{l,\tau} and RDsl,τR_{D_s}^{l,\tau}, they may be more sensitive to the QCD dynamics which controls the B/Bs(D(),Ds())B/B_s \to (D^{(*)},D_s^{(*)}) transitions than the old ratios, we therefore strongly suggest LHCb and the forthcoming Super-B experiments to measure these new ratios.
Note:
  • 23 pages, 3 figures and 7 tables. Some references are updated. Final version being published in Chinese Science Bulletin
  • quantum chromodynamics: perturbation theory
  • quantum chromodynamics: sum rule
  • quantum chromodynamics: light cone
  • B: semileptonic decay
  • B/s: semileptonic decay
  • B: branching ratio
  • B/s: branching ratio
  • branching ratio: ratio
  • decay: form factor
  • form factor: calculated