2025/02/27 by Md Isha Ali, Ali, Md Isha, Utpal Chattopadhyay +5
Physics and Astronomy · Computer Science · #Particle physics theoretical and experimental studies #Computational Physics and Python Applications #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.2502.20145
The flavor-changing neutral current semileptonic decays of B mesons provide an excellent platform for indirectly probing New Physics (NP) beyond the Standard Model (SM). Recent measurements of lepton flavor universality (LFU) ratios such as RK, RK^*, and Rϕ are consistent with SM predictions, thereby reducing earlier hints of LFU violation. Nevertheless, notable tensions persist in individual branching fractions -- for instance B(B+ → K+ μ+ μ-) and B(B+ → K+ e+ e-), which deviate at the 4σ--5σ level in the low-q2 region ([1.1,6] GeV2). Similarly, the angular observable P'5 in B → K* μ+ μ- shows a 3.3σ deviation, while B(Bs → ϕμ+ μ-) departs from the SM by 3.6σ. Although such discrepancies could in principle originate from underestimated hadronic effects, they may also indicate possible NP contributions. In this work, we perform a global fit to the latest b → s ℓ+ ℓ- data within the framework of dimension-6 SMEFT operators. Our analysis systematically incorporates hadronic uncertainties from form factors, non-factorizable corrections, and input parameters, thereby providing a balanced assessment of the NP interpretation. We allow for NP contributions not only in b → s μ+ μ- transitions but also in b → s e+ e- channels, thus testing both lepton flavor universal (LFU) and lepton flavor universality violating (LFUV) NP scenarios. The interplay between these possibilities yields distinctive signatures in branching fractions, angular observables, and Δ-observables, offering a comprehensive view of the current flavor anomalies.