From B-meson anomalies to Kaon physics with scalar leptoquarks

Abstract

In this work we study possible connections between B-meson anomalies and Kaon physics observables in the context of combined solutions with the singlet and triplet scalar leptoquarks S_1 and S_3. By assuming a flavor structure for the leptoquark couplings dictated by a minimally broken U(2)^5 flavor symmetry we can make a sharp connection between these two classes of observables. We find that the bound on {mathcal {B}}(K^+ rightarrow pi ^+ nu nu ) from NA62 puts already some tension in the model, while the present limits on {mathcal {B}}(K_L rightarrow mu ^+ mu ^-) and mu rightarrow e conversion in nuclei can be saturated. Relaxing instead the flavor assumption we study what values for {mathcal {B}}(K^+ rightarrow pi ^+ nu nu ), as well as for {mathcal {B}}(K_L rightarrow pi ^0 nu nu ) and {mathcal {B}}(K_{L,S} rightarrow mu ^+ mu ^-), are viable compatibly with all other phenomenological constraints.