Abstract
In this article, we predict the standard model (SM) values of the asymmetric and angular observables in Brightarrow D^{(*)}tau nu _{tau } decays, using the results of the new up-to-date analysis in Brightarrow D^{(*)}ell nu _{ell }. We also revisit the SM prediction of the inclusive ratio {mathcal {R}}_{X_c}, and we give its values in different schemes of the charm quark mass. This is the first analysis which includes all the known corrections in the SM. In addition, we analyze the brightarrow ctau nu _tau decay modes in a model-independent framework of effective field theory beyond the standard model. Considering all the possible combinations of the effective operators in b rightarrow c tau nu _{tau } decays and using the Akaike information criterion, we find the scenarios which can best explain the available data on these channels. In the selected scenarios, best-fit values and correlations of the new parameters are extracted. Using these results, predictions are made on various observables in the exclusive and inclusive semitaunic b rightarrow c decays. The graphical correlations between these observables are shown, which are found to be useful in discriminating various new physics scenarios.
Highlights
The semileptonic B → D(∗) ν ( = μ or e) decays play an important role in the extraction of |Vcb| as well as in the extraction of the form factors associated with the b → c decays
The current lattice results suggest that the heavy quark effective theory (HQET) values of form factors at zero recoil are not in complete agreement with those from lattice [1,3]
Page 7 of 30 268 consider the new physics (NP) Wilson coefficients occurring in Eq (4) to be complex, all possible combinations of the real and imaginary parts of the coefficients (10 parameters in total) should constitute such a predefined set, from which we can choose different scenarios
Summary
The semileptonic B → D(∗) ν ( = μ or e) decays play an important role in the extraction of |Vcb| as well as in the extraction of the form factors associated with the b → c decays These form factors are the major input used in the predictions of RD(∗) = B(B → D(∗)τ ντ )/B(B → D(∗) ν ), where = μ or e; for recent updates see [1,2,3,4,5,6,7]. The current lattice results suggest that the HQET values of form factors at zero recoil are not in complete agreement with those from lattice [1,3]. With all this input and using the Caprini–Lellouch–Neubert (CLN) [11]
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