Charge gap in SU(3) Yang–Mills-plus-nonlinear-spinor-field theory Vladimir Dzhunushaliev, Vladimir Folomeev and Daulet Berkimbayev Eur. Phys. J. C, 83 6 (2023) 546 Published online: 29 June 2023 DOI: 10.1140/epjc/s10052-023-11714-5