Anomalous enhancement observed inB→D(*)τν¯τdecays

Abstract

The BaBar measurements of the ratios R(D ( * ) ) = B(B→D ( * ) τντ ) B(B→D ( * ) µνµ) deviate from the standard model expectation, while new results on the purely leptonic B → τντ mode show a better consistency with the standard model, within the uncertainties. In a new physics scenario, one possibility to accomodate these two experimental facts consists in considering an additional tensor operator in the effective weak hamiltonian. We study the effects of such an operator in a set of observables, in semileptonic B → D ( * ) modes as well as in semileptonic B and Bs decays to excited positive parity charmed mesons.

Status of B to D(*) τ ν decays in two-Higgs-doublet models

“…[4,10,[15][16][17][18]. These observables can be useful to disentangle different kinds of new physics in b → cτν transitions and more importantly to our discussion, they can be used to test for charged scalar contributions independently of the flavour structure of its fermionic couplings.…”

Supersymmetric SU(5) grand unification for a post Higgs boson era

“…The latest Belle and BaBar results for the purely leptonic B → τ ν τ decay [43], measured the branching ratio Br (B → τ ν τ ) = (1.12 ± 0.22) × 10 −4 , which can be compared with the SM prediction of (0.79 ± 0.23) × 10 −4 [44]. MicrOMEGAS outputs the ratio of the predicted branching ratio with that of the SM, R τ ντ .…”

New physics in the kinematic distributions of B¯→D(*)τ−(→

“…Scenarios of this type could explain the R D ( * ) anomalies with NP at a scale of Λ ∼ 1 TeV, as discussed in refs. [11,19,20,22,[24][25][26][27].…”

“…The discrepancy between experiment and the SM is at the level of 4σ, and it can be explained with new physics (NP) [11,[15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]. These analyses of the data are most fruitful when casted model-independently in an effective field theoretical framework.…”