2
$\begingroup$

We know that in the Standard Model (SM) neutrinos are massless. But the discovery of neutrino oscillation suggests that neutrinos must have masses because only then there will be a mass basis for neutrinos and neutrinos will mix among each other through the PMNS matrix $U_\text{PMNS}$. Now my question is:

Couldn't we explain the neutrino oscillation through the Flavor Changing Neutral Currents (FCNC) or some other Beyond-SM phenomena so that neutrinos remain massless?

Improve this question
$\endgroup$
3
  • $\begingroup$ What mechanism/notional diagram would you have in mind? If $\nu_e,\nu_\mu,\nu_\tau$ were degenerate null-mass eigenstates, what would make them change? $\endgroup$
    – Cosmas Zachos
    Commented Nov 13, 2021 at 14:44
  • $\begingroup$ A BSM interaction of kind S$\nu_e\nu_\mu$, where S is some scalar particle. $\endgroup$
    – Praveen Bharadwaj
    Commented Nov 14, 2021 at 7:28
  • $\begingroup$ It all depends on whether your S has a v.e.v. or not. If yes, then you have a mass matrix, to diagonalize, so your neutrinos are not massless to start with, just like the SM neutrinos, which may well have a mass through standard SM Yukawa couplings. If someone starts bloviating to you that the SM does not allow neutrino masses, walk away. Run! $\endgroup$
    – Cosmas Zachos
    Commented Nov 14, 2021 at 14:08

0

Reset to default

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.