Explaining the B → K μ + μ − anomaly in the left-right inverse seesaw model

We investigate the long-standing anomaly in the rare decay B → K μ + μ − within the left-right inverse seesaw (LRIS) model. Global analyses of the b → s μ + μ − data consistently indicate a significant negative shift in the vector Wilson coefficient, Δ C 9 μ ≈ − 1 , while the axial coefficient Δ C 10 μ remains consistent with zero. We show that a charged-scalar/heavy-neutrino box diagram in the LRIS model naturally generates these values for the Wilson coefficients through a mechanism: the right-handed coupling Y μ N R ∝ M N i / v R produces a contribution to Δ C 9 μ that is unsuppressed in the heavy-neutrino limit, while the simultaneous presence of a comparable left-handed Dirac Yukawa coupling Y μ N L ensures the automatic cancellation Δ C 10 μ ≈ 0 . The potentially dangerous contribution to B s − B ¯ s mixing is controlled by the usual Glashow–Iliopoulos–Maiani suppression associated with the top-quark loop, keeping it safely below current experimental bounds throughout the viable parameter space. In addition, a specific right-handed phase texture in the right-handed quark mixing matrix, whose origin can be traced to a discrete Z 2 symmetry in the right-handed quark sector, provides a technically natural and radiatively stable structural feature of the model. A numerical scan over the model parameter space identifies a viable region with y ≡ | Y t s , t b H | ≈ 0.39 and M H ± ≳ 600 GeV , consistent with current flavor and collider experimental constraints.