Proton decay and axion dark matter in SO(10) grand unification via minimal left–right symmetry Yuta Hamada, Masahiro Ibe, Yu Muramatsu, Kin-ya Oda and Norimi Yokozaki Eur. Phys. J. C, 80 5 (2020) 482 Published online: 28 May 2020 DOI: 10.1140/epjc/s10052-020-7922-x