Analysis of b → cτ ¯ ν τ anomalies using weak effective Hamiltonian with complex couplings and their impact on various physical observables

Abstract

Abstract B Meson anomalies triggered an interest as experimental measurements of the branching ratios and different polarization asymmetries by BABAR, Belle and LHCb have shown differences in the Standard Model (SM) predictions. In this work we address the complex WCs coupling by adding the dimension-six vector, (pseudo-)scalar, and tensor operators using model-independent weak effective Hamiltonian (WEH) with the assumption of left-handed neutrinos and with constraints coming from the leptonic branching ratio of charmed-meson. We analyze the parameter space of the new physics (NP) WCs that can explain the anomalies for the most recent data from HFLAV summer 2023. We find that the allowed parametric region of left-handed scalar couplings heavily depends on the constraints of the Bc branching ratio, and the maximum pull from the SM predictions comes for its 60 percent limit. And parametric region changes if we add LHCb data and extend our analysis. Furthermore, we derive the sum rules that correlate these observables with the LFU ratio of D and D* mesons and due the large errors in the experimental measurements of considered experimental observables, we predict these observables in terms of the LFU ratio of D and D* mesons. We find that the most significant impact of NP arises from the WC CSL= 4CT. Finally, we investigate the impact of these NP couplings on various angular and CP-triple product asymmetries. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.