Measurements of μ → 3e decay with polarised muons as a probe of new physics

Working within the Standard Model effective field theory approach, we examine possibility to test charged lepton flavour violating (cLFV) new physics (NP) by angular measurements of outgoing electron and positrons in polarised μ+→e+e+e− decay. This decay is planned be studied with a sensitivity branching ratio Bμ→3e∼10−15 Mu3e experiment at PSI. To illustrate potential these measurements, consider set eight operators generating tree level, including dimension-five dipole dimension-six scalar vector four-fermion different chiralities. We show that if observed induced single operator, data from three observables – two P-odd asymmetries one T-odd asymmetry can allow discriminate between all considered exception opposite chirality. For types operators, maximal magnitude; they distinguished, principle, measuring helicities positrons. The observation non-zero would indicate presence rate operator interference term T (CP) violating.