# Baroque neutrinos and Zee-Babu model

## Main Question or Discussion Point

https://arxiv.org/abs/1810.01000
MiniBooNE, MINOS+ and IceCube data imply a baroque neutrino sector
Jiajun Liao, Danny Marfatia, Kerry Whisnant
(Submitted on 1 Oct 2018)
The 4.8σ anomaly in MiniBooNE data cannot be reconciled with MINOS+ and IceCube data within the vanilla framework of neutrino oscillations involving an eV-mass sterile neutrino. We show that a consistent picture can be drawn if charged-current and neutral-current nonstandard neutrino interactions are at work in the 3+1 neutrino scheme. It appears that either the neutrino sector is more elaborate than usually envisioned, or one or more datasets needs revision.

This paper discusses the hypothetical new interactions only at the effective level (eqns 1 & 2) and doesn't say anything about what the underlying physics might be. However, via their ref 13, I have become aware of the "Zee-Babu model", which produces neutrino mass, not with right-handed neutrinos, but with two new scalars, of charge +1 and +2. Apparently this also contains the two kinds of nonstandard interaction required.

But since this paper is about extending the "3+1 neutrino scheme", it seems that we would be talking about three left-handed neutrinos, three right-handed neutrinos, a 1 eV sterile neutrino, and the two Zee-Babu scalars. Well, they did call it baroque...

Related Beyond the Standard Model News on Phys.org
ohwilleke
Gold Member
There are lots of reasons to disfavor this model.

For example, the astronomy data strongly disfavors the existence of a 1 eV right handed neutrino that oscillates with ordinary neutrinos (at more than 5 sigma).

The MiniBoone analysis resonance shape isn't right for a new neutrino. And, the MiniBoone analysis doesn't correct for shifting proportions of reactor fuel which have been shown to materially affect background expectations from the SM three massive neutrino model.

Other neutrino oscillation studies using reactors also don't see the 3+1 in their data and indeed rule it out.

There is also no evidence whatsoever for lepton number violation that would be expected in a Majorana neutrino model.