Is the muon a third family lepton?

TL;DR

The paper explores a new family structure in the Standard Model where the muon is assigned to the third family, revealing potential physical implications and testable predictions in the presence of new physics linking quarks and leptons.

Contribution

It introduces a novel family assignment for the muon in the Standard Model that becomes physically meaningful with new quark-lepton interactions, leading to testable experimental predictions.

Findings

Reassignment of muon to the third family affects mass and mixing patterns.

Predicts specific experimental signatures in quark-lepton interactions.

Suggests new physics scenarios linking quark and lepton families.

Abstract

We propose a new family structure for the Standard Model fermions, where the muon is assigned to the third family, taking the placeholder from the tau lepton. This reassignment, which is a mere choice of convention in the Standard Model, becomes physically meaningful in the presence of new physics assuming a direct link between quarks and leptons. In fact, when quark and leptons are coupled by new interactions, the choice of which lepton is assigned to a particular quark generation brings physical consequences, revealing potentially meaningful patterns in the masses and mixings, while pointing to precise and testable predictions for experiments.