Eight very excited flux tube spectra and possible axions in SU(3) lattice gauge theory
Alireza Sharifian, Nuno Cardoso, Pedro Bicudo
Abstract
We compute the spectra of flux tubes formed between a static quark-antiquark pair up to a significant number of excitations and for eight symmetries of the flux tubes, up to ${\mathrm{\ensuremath{\Delta}}}_{u}$, using pure SU(3) gauge lattice QCD in $3+1$ dimensions. To accomplish this goal, we use a large set of appropriate operators, an anisotropic tadpole improved action, smearing techniques, and solve a generalized eigenvalue problem. Moreover, we compare our results with the Nambu-Goto string model to evaluate possible tensions which could be a signal for novel phenomena. Especially, we provide evidence for the coupling of a massive particle, say, an axion, to the ${\mathrm{\ensuremath{\Sigma}}}_{g}^{\ensuremath{-}}$, ${\mathrm{\ensuremath{\Sigma}}}_{u}^{\ensuremath{-}}$, and ${\mathrm{\ensuremath{\Sigma}}}_{u}^{\ensuremath{-}*}$ flux tube with approximate masses $2.25\sqrt{\ensuremath{\sigma}}$, $1.85\sqrt{\ensuremath{\sigma}}$, and $3.30\sqrt{\ensuremath{\sigma}}$, respectively.