Speaker
Description
We investigate the low-lying flavour-singlet spectrum of an $Sp(4)$ lattice gauge theory with fermions in both the fundamental and two-index antisymmetric representations, using the Wilson gauge action and Wilson fermions. Our analysis employs a generalized eigenvalue problem on a basis of smeared interpolating operators comprising glueball and meson operators from both fermion representations in two large ensembles with the same inverse coupling and similar quark mass parameters. A first determination of the spectrum shows that the lightest flavour-singlet state is a scalar. We observe evidence for meson–glueball mixing. We improve upon previous determinations of the energy eigenstates and mixing angles in the flavour-singlet pseudoscalar sector.