# Mixing matrix in particle physics

It is familiar for us that the diagonalization of a mixing matrix which is written in the neutral basis gives the masses of the neutral particles.

If I construct a mixing matrix which is written in the basis ($$X_1, X_2, X_3$$) and ($$N_1, N_2, N_3$$) where $$X_i (i=1,2,3)$$ are charged particles while $$N_i (i=1,2,3)$$ are neutral. This mixing matrix has any physical sense?

• The PMNS matrix in SM neutrino physics connects charged lepton mass eigenstates to neutral neutrino mass eigenstates and Ws. It is not a mass matrix, but a coupling mixing matrix. Is that what you might have in mind? – Cosmas Zachos Sep 30 '19 at 19:24
• Actually, I have developed a lagrangian in a model beyond the standard model, and I found some terms represent the coupling between charged and neutral leptons as (E^-. Neutrino) where E^- is a charged lepton. and I wanted to know if it's okay to find those terms or its wrong. – Narmine Oct 2 '19 at 8:33
• Looks like they violate electric charge? – Cosmas Zachos Oct 2 '19 at 11:07
• I found many terms represent couplings between charged and neutral leptons as (E^-. Beta^0) and (beta^+. Neutrino) and many others I don't understand how can I deal with them. Are those forbidden terms? – Narmine Oct 3 '19 at 7:45
• Yes, they are., unless there also is a W there. – Cosmas Zachos Oct 3 '19 at 11:11