PT Journal
AU Kim, CS
   Lopez-Castro, G
   Tostado, SL
   Vicente, A
TI Remarks on the Standard Model predictions for R(D) and R(D*)
SO Physical Review D
JI Phys. Rev. D
PY 2017
BP 013003
EP 7pp
VL 95
IS 1
DI 10.1103/PhysRevD.95.013003
LA English
AB Semileptonic b -> c transitions, and in particular the ratios R(D-(*())) = Gamma(B -> D-(*())tau nu)/Gamma(B -> D-(*())l nu), can be used to test the universality of the weak interactions. In light of the recent discrepancies between the experimental measurements of these observables by the BABAR, Belle, and LHCb collaborations and the Standard Model predicted values, we study the robustness of the latter. Our analysis reveals that R(D) might be enhanced by lepton mass effects associated to the mostly unknown scalar form factor. In contrast, the Standard Model prediction for R(D*) is found to be more robust, because possible pollutions from B* contributions turn out to be negligibly small; this indicates that R(D) is a promising observable for searches of new physics.
ER