Scalar leptoquarks in leptonic processes

Leptoquarks are hypothetical new particles, which couple quarks directly to leptons. They experienced a renaissance in recent years as they are prime candidates to explain the so-called flavor anomalies, i.e. the deviations between the Standard Model predictions and measurements in b -> sl(+)l(-) and b -> c tau nu processes and in the anomalous magnetic moment of the muon. At the one-loop level these particles unavoidably generate effects in the purely leptonic processes like Z -> l(+)l(-), Z -> v (v) over bar, W -> l nu and h -> l(+)l(-) and can even generate non-zero rates for lepton flavor violating processes such as l -> l 'gamma, Z -> l(+)l '(-), h -> l(+)l '(-) and l -> 3l '. In this article we calculate these processes for all five representations of scalar Leptoquarks. We include their most general interaction terms with the Standard Model Higgs boson, which leads to Leptoquark mixing after the former acquires a vacuum expectation value. In our phenomenological analysis we investigate the effects in modified lepton couplings to electroweak gauge bosons, we study the correlations of the anomalous magnetic moment of the muon with h -> mu(+)mu(-) and Z -> mu(+)mu(-) as well as the interplay between different lepton flavor violating decays.

Automated summary

Leptoquarks are hypothetical new particles that couple quarks directly to leptons. Recent research suggests they may explain flavor anomalies in the Standard Model predictions, generating effects in various quark and lepton processes.