Yang-Mills Glueball Masses from Spectral Reconstruction

We compute masses of the two lightest glueballs from spectral reconstructions of timelike interaction channels of the four-gluon vertex in Landau gauge Yang-Mills theory. The Euclidean spacelike dressings of the vertex are calculated with the functional renormalisation group. For the spectral reconstruction of these Euclidean data, we employ Gaussian process regression. The glueball resonances can be identified straightforwardly and we obtain m_sc = 1870(75) MeV as well as m_ps = 2700(120) MeV, in accordance with functional bound state and lattice calculations.