Spontaneous proton decay and the origin of Peccei-Quinn symmetry

TL;DR

This paper reinterprets the Peccei-Quinn symmetry as the axial B+L symmetry within the Standard Model, leading to spontaneous proton decay and linking axion behavior to neutrino mass generation, with testable low-energy predictions.

Contribution

It introduces a novel interpretation of Peccei-Quinn symmetry as axial B+L symmetry, connecting axion physics with proton decay and neutrino masses.

Findings

Proposes spontaneous proton decay linked to axion decay constant.

Identifies axion as a Majoron-like particle affecting neutrino masses.

Suggests low-energy processes to test the new symmetry interpretation.

Abstract

We propose a new interpretation of Peccei-Quinn symmetry within the Standard Model, identifying it with the axial $B + L$ symmetry i.e. $U(1)_{PQ} \equiv U(1)_{\gamma_5(B+L)}$. This new interpretation retains all the attractive features of Peccei-Quinn solution to strong CP problem but in addition also leads to several other new and interesting consequences. Owing to the identification $U(1)_{PQ} \equiv U(1)_{\gamma_5(B+L)}$ the axion also behaves like Majoron inducing small seesaw masses for neutrinos after spontaneous symmetry breaking. Another novel feature of this identification is the phenomenon of spontaneous (and also chiral) proton decay with its decay rate associated with the axion decay constant. Low energy processes which can be used to test this interpretation are pointed out.