Spectrum of QCD with one flavor: A window for supersymmetric dynamics

We compute the spectrum of the low-lying mesonic states with vector, scalar and pseudoscalar quantum numbers in QCD with one flavor. With three colors the fundamental and the two-index antisymmetric representations of the gauge group coincide. The latter is an orientifold theory that maps into the bosonic sector of <math display="inline"><mi mathvariant="script">N</mi><mo>=</mo><mn>1</mn></math> super Yang-Mills theory in the large number of colors limit. We employ Wilson fermions along with tree-level improvement in the gluonic and fermionic parts of the action. In this setup the Dirac operator can develop real negative eigenvalues. We therefore perform a detailed study in order to identify configurations where the fermion determinant is negative and eventually reweight them. We finally compare results with effective field theory predictions valid in the large <math display="inline"><msub><mi>N</mi><mi>C</mi></msub></math> limit and find reasonably consistent values despite <math display="inline"><msub><mi>N</mi><mi>C</mi></msub></math> being only three. Additionally, the spin-one sector provides a novel window for supersymmetric dynamics.