The paper mentions leptoquarks (particles that interact with leptons and quarks with potentially different coupling strengths for different leptons therefore br

The paper mentions leptoquarks (particles that interact with leptons and quarks with potentially different coupling strengths for different leptons therefore breaking lepton universality) or some unknown heavy (didn't look into it any further but I guess the heavy requirement is there because otherwise we would already have observed its effects, I don't think it's necessary for this particular observation) neutral boson that would for example allow flavor changing of leptons ("flavor" means whether it is an electron, muon our tau lepton). Edit: https://arxiv.org/pdf/2103.11769.pdf https://arxiv.org/pdf/2103.11769.pdf - references 54 to 90 are about potential new physics models.