Semileptonic Decays
The following is an overview of the measurements of the CKM matrix elements |V{sub cb}| and |V{sub ub}| that are based on detailed studies of semileptonic B decays by the BABAR and Belle Collaborations and major advances in QCD calculations. In addition, a new and improved measurement of the ratios R(D{sup (*)}) = {Beta}({bar B} {yields} D{sup (*)}{tau}{sup -}{bar {nu}}{sub {tau}})/{Beta}({bar B} {yields} D{sup (*)}{ell}{sup -}{bar {nu}}{sub {ell}}) is presented. Here D{sup (*)} refers to a D or a D* meson and {ell} is either e or {mu}. The results, R(D) = 0.440 {+-} 0.058 {+-} 0.042 and R(D*) = 0.332 {+-} 0.024 {+-} 0.018, exceed the Standard Model expectations by 2.0{sigma} and 2.7{sigma}, respectively. Taken together, they disagree with these expectations at the 3.4{sigma} level. The excess of events cannot be explained by a charged Higgs boson in the type II two-Higgs-doublet model.
- Research Organization:
- SLAC National Accelerator Laboratory (SLAC)
- Sponsoring Organization:
- US DOE Office of Science (DOE SC); High Energy Physics (HEP)
- DOE Contract Number:
- AC02-76SF00515
- OSTI ID:
- 1050851
- Report Number(s):
- SLAC-PUB-15245; arXiv:1209.4674
- Journal Information:
- arXiv:1209.4674v2, Journal Name: arXiv:1209.4674v2
- Country of Publication:
- United States
- Language:
- English
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