Model independent constraints on four-lepton operators

TL;DR

This paper derives model-independent constraints on four-lepton operators using a comprehensive set of experimental data, providing confidence intervals for Wilson coefficients without assuming flavor structure.

Contribution

It offers the first flavor-independent constraints on 16 four-lepton operators from diverse experimental inputs, including LEP, W decays, neutrino scattering, and parity violation.

Findings

Confidence intervals for 16 Wilson coefficients obtained.

Full correlation matrix provided for the operators.

Implications for leptophilic beyond Standard Model theories discussed.

Abstract

We obtain constraints on four-lepton interactions in the effective field theory with dimension-6 operators. To this end, we combine the experimental input from Z boson measurements in LEP-1, W boson mass and decays, muon and tau decays, lepton pair production in LEP-2, neutrino scattering on electrons, and parity violating electron scattering. The analysis does not rely on any assumptions about the flavor structure of the dimension-6 operators. Our main results are the confidence intervals for Wilson coefficients of 16 lepton-flavor conserving four-lepton operators, together with the full correlation matrix. Consequences for leptophilic models beyond the Standard Model are discussed.