New Observables in Lepton-Flavor Universality Violation Identified in B Decays

Recent research has identified genuine lepton-flavor universality violating (LFUV) observables in the ( \tau-\mu ) sector of ( B \to (K, K^) \ell \ell ) decays. The study, conducted by Ashutosh Kumar Alok and colleagues, highlights that the ratios ( R_K^{\tau \mu} ) and ( R_{K^}^{\tau \mu} ) can deviate from Standard Model predictions, even with universal new physics couplings. This finding emphasizes the importance of establishing genuine LFUV observables in this sector.

The authors conducted a comprehensive analysis of angular distributions in ( B \to K \ell \ell ) and ( B \to K^ \ell \ell ) decays. They determined that while certain ratios like ( R_{K^}^{\tau \mu} ) do not qualify as genuine LFUV observables, others, particularly those optimized in the ( B \to K^* \ell \ell ) decays, do. Notably, the ratio ( \Gamma_\tau(1-F_{H}^{\tau})/\Gamma_\mu(1-F_{H}^{\mu}) ) was identified as the sole genuine LFUV observable in ( B \to K \ell \ell ) decays.

The implications of these findings are significant for future research in particle physics, particularly in understanding the behavior of lepton flavors and potential new physics beyond the Standard Model. The study is available for further reading at arXiv:2405.18488.