Revisiting B_s → PP and PV Decays with Contributions from Φ_b2 with the Perturbative QCD Approach

The B_s → PP and PV decay modes are revisited at leading order within the perturbative QCD (pQCD) approach, incorporating the B_s mesonic wave function (WF) ϕ_B2 . Here, P represents the pseudoscalar mesons π and K, while V denotes the ground-state vector mesons. The investigation incorporates two key refinements: the contribution of the subleading-twist WF ϕ _B2 of the B_s meson and the effects of higher-order terms in the distribution amplitudes (DAs) of the final-state mesons. We emphasize that ϕ _B2 is not merely a numerical correction, but a necessary ingredient to preserve gauge invariance. Employing the minimum χ ^2 method, we optimize the shape parameter ω _B_s of the B_s meson WF and systematically calculate the branching ratios and CP violation parameters for these decay modes. Our results demonstrate that the inclusion of ϕ _B2 significantly impacts both the branching ratios and CP asymmetries, resulting in better agreement with existing experimental data for specific channels. This underscores the need to account for ϕ _B2 in theoretical studies of B_s weak decays. While the higher-order corrections in the final-state meson DAs yield comparatively smaller effects, they still enhance the theoretical predictions. These findings highlight the importance of refining both WF modeling and higher-order contributions in pQCD calculations. Future high-precision experimental measurements will further test these predictions, while continued theoretical efforts are essential for exploring additional interaction mechanisms and systematic uncertainties. The interplay between experimental advancements and theoretical improvements remains critical for a deeper understanding of B_s meson decay dynamics.