Charged current b→cτν¯τ anomalies in a general W′ boson scenario

Abstract

The very recent experimental information obtained from Belle experiment, along with the one accumulated by the BABAR and LHCb experiments have shown the existence of anomalies in the ratios R(D) and R(D * ) associated with the charged current transition b → cτντ . Although the Belle measurements are in agreement with the SM predictions, the new experimental world averages still exhibit a tension. In addition, the D * longitudinal polarization FL(D * ) related with the channel B → D * τντ observed by the Belle and the ratio R(J/ψ) measured by the LHCb also show discrepancies with their corresponding SM estimations. In this work, we present a modelindependent study based on the most general effective Lagrangian that yields to a tree-level effective contribution to the transition b → cτντ induced by a general W gauge boson. Instead of considering any specific new physics (NP) realization, we performed an analysis by considering all the different chiral charges to the charm-bottom and τ -ντ interaction terms with a charged W boson that explain the anomalies. We present a phenomenological study of parameter space allowed by the new experimental b → cτντ data and with the mono-tau signature pp → τ h X + MET at the LHC. For comparison, we include some of the W boson NP realizations that have already been studied in the literature.

Investigation of effects of new physics in Λb→ΛcτνMu1, Li2, Zou3 et al. 2019Phys. Rev. D380130View full textAdd to dashboardCite

“…Very recently, in Ref. [119], the authors performed a χ 2 analysis within the latest experimental data and got the best fitted values ϵ L cb ϵ L τν τ ¼ 0.11 with M W 0 ¼ 1 TeV, which also agrees with previous studies. So, based on the above discussions and results in Table I, in order to maximize the effects of NP, we adopt the range as…”

“…One simple way to obtain a new physics contribution to b → cτν τ is to use W 0 gauge boson which couples to the second-and third-generation fermions [118]. Without the right-handed neutrinos, the general Lagrangian that describes the couplings of an extra W 0 boson to quarks and leptons can be written as [119]…”

“…(59), many works have been preformed by analyzing the RðD ðÃÞ Þ anomalies, such as in Refs. [119,[121][122][123]. In Ref.…”

Clustering of $$ \overline{B}\to {D}^{\left(\ast \right)}{\tau}^{-}{\overline{\nu}}_{\tau } $$ kinematic distributions with ClusterKinG

“…In this article, we use this package to cluster kinematic distributions ofB → D ( * ) τ −ν τ decays. These decays are of particular interest in view of the current B anomalies [31][32][33][34][35][36][37][38][39].…”

D * Polarization as an Additional Constraint on New Physics in the b → cτ ν ¯ τ Transition

“…However, at the same time, they suffer from stringent experimental constraints coming from various processes, also including direct searches at the Large Hadron Collider (LHC). Details on these models can be found in the recent papers [20][21][22][23][24][25][26] and references therein. In the second approach, one starts with a general effective Hamiltonian for the weak b → c ν transition that includes both the SM and beyond-SM contributions in the form of dimension-six four-fermion operators.…”