Analysis of $b\to c\tau {\bar{\nu }}_{\tau }$ anomalies using weak effective Hamiltonian with complex couplings

Abstract

Recently, the experimental measurements of the branching ratios and different polarization asymmetries for the processes occurring through flavor-changing-charged current $b\to c\tau {\overline{\nu }}_{\tau }$ transitions by BABAR, Belle, and LHCb show some sparkling differences with the corresponding SM predictions. Assuming the left handed neutrinos, we add the dimension-six vector, (pseudo-)scalar, and tensor operators with complex WCs to the SM WEH. Together with 60%, 30% and 10% constraints coming from the branching ratio of $B_c\to \tau {\bar{\nu }}_{\tau }$, we analyze the parametric space of these new physics WCs accommodating the current anomalies in the purview of the most recent HFLAV data of $R_{\tau /\mu ,e}\left(D\right)$, $R_{\tau /\mu ,e}\left(D^{\ast }\right)$ and Belle data of $F_L\left(D^{\ast }\right)$ and $P_{\tau }\left(D^{\ast }\right)$. Furthermore, we derive the sum rules which correlate these observables with $R_{\tau /\mu ,e}\left(D\right)$ and $R_{\tau /\mu ,e}\left(D^{\ast }\right)$. Using the best-fit points of the new complex WCs along with the latest measurements of $R_{\tau /\mu ,e}\left(D^{(\ast )}\right)$, we predict the numerical values of the observable $R_{\tau /\ell }\left({\Lambda }_c\right)$, $R_{\tau /\mu }\left(J/\psi \right)$ and $R_{\tau /\ell }\left(X_c\right)$ from the sum rules. Apart from finding the correlation matrix among the observables under consideration, we plot them graphically which is useful to discriminate different NP scenarios. Finally, we study the impact of these NP couplings on various angular and the CP triple product asymmetries, that could be measured in some ongoing and future experiments. The precise measurements of these observables are important to check the SM and extract the possible NP.

21 pages, 6 figures, The numerical analysis is modified, and the Table III is added to elaborate and to perform the quantitative analysis of the observables

References in corpus (21)

• B-physics anomalies: a guide to combined explanations
• On the B to D* tau nu Sensitivity to New Physics
• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of 2021
• The lifetime of the $B_c^{-}$ meson and the anomalies in $B\to D^{(\ast )}\tau \nu$
• $R(D^{\ast })$, $|V_{cb}|$, and the Heavy Quark Symmetry relations between form factors
• Measurement of the $\tau$ lepton polarization and $R(D^{\ast })$ in the decay $\bar{B}\to D^{\ast }{\tau }^{-}{\bar{\nu }}_{\tau }$ with one-prong hadronic $\tau$ decays at Belle
• Renormalization-group evolution of new physics contributions to (semi)leptonic meson decays
• Extraction of $|V_{cb}|$ from $B\to D^{(\ast )}\ell {\nu }_{\ell }$ and the Standard Model predictions of $R(D^{(\ast )})$
• The $V_{cb}$ puzzle: an update
• New Physics effect on $B_c\to J/\psi \tau \bar{\nu }$ in relation to the $R_{D^{(\ast )}}$ anomaly
• Constraint on the branching ratio of B_c \to tau nu from LEP1 and consequences for R(D(*)) anomaly
• Constraints on Lepton Universality Violation from Rare $B$ Decays
• New Physics in the Visible Final States of $B\to D^{(\ast )}\tau \nu$
• The Azimuthal $B\to D^{\ast }{\tau }^{-}\overline{{\nu }_{\tau }}$ Angular Distribution with Tensor Operators
• Measurement of the ratios of branching fractions $\mathcal{R}(D^{\ast })$ and $\mathcal{R}(D^0)$
• Test of lepton flavour universality using $B^0\to D^{\ast -}{\tau }^{+}{\nu }_{\tau }$ decays with hadronic $\tau$ channels
• B-meson charged current anomalies: the post-Moriond status
• Observation of the ${\Lambda }_b^0\to J/\psi p{\pi }^{-}$ decay
• Investigation of Effects of New Physics in ${\Lambda }_b\to {\Lambda }_c\tau {\bar{\nu }}_{\tau }$ Decay
• Impact of ${\Lambda }_b\to {\Lambda }_c\tau \nu$ measurement on New Physics in $b\to cl\nu$ transitions
• A Measurable Angular Distribution for $\bar{B}\to D^{\ast }{\tau }^{-}{\bar{\nu }}_{\tau }$ Decays

Cited by in corpus (3)

• Addressing the $R_{\tau /\mu ,e}\left(D^{(\ast )}\right)$ puzzle through New Physics four-fermion operators and their impact on ${\Lambda }_b\to {\Lambda }_c\tau {\bar{\nu }}_{\tau }$ decay
• The Angular Observables of ${\Lambda }_b\to {\Lambda }_c(\to {\Lambda }^0{\pi }^{+}){\tau }^{-}(\to {\pi }^{-}{\nu }_{\tau }){\bar{\nu }}_{\tau }$ within the Paradigm of FCCC Anomalies
• ${\eta }_c$ leading-twist distribution amplitude and the $B_c\to {\eta }_c\ell {\bar{\nu }}_{\ell }$ semileptonic decays using QCD Sum Rules