Model independent constraints on leptoquarks from b -> s l+ l- processes

TL;DR

This paper systematically analyzes scalar and vector leptoquarks affecting b -> s l+ l- decays, establishing model-independent constraints on their contributions using experimental data.

Contribution

It identifies all relevant leptoquark states and derives bounds on their Wilson coefficients based on experimental decay measurements.

Findings

Only two baryon number-violating vector leptoquarks induce scalar and pseudoscalar operators.

Scalar states contribute to these operators only with pairs of same-charge states.

Experimental decay data constrains the Wilson coefficients of the relevant operators.

Abstract

We list all scalar and vector leptoquark states that contribute to the b -> s l+ l- effective Hamiltonian. There are altogether three scalar and four vector leptoquarks that are relevant. For contribution of each state we infer the correlations between effective operators and find that only two baryon number-violating vector leptoquarks give rise to scalar and pseudoscalar four-fermion operators, whereas the scalar states can contribute to those operators only when two states with same charge are present. We bound the resulting Wilson coefficients by imposing experimental constraints coming from branching fractions of B -> K l+ l-, B_s -> mu+ mu-, and B -> X_s mu+ mu- decays.