  When the multiplicities of particles produced in heavy-ion collisions are
fitted to the hadron-resonance-gas model, excluded-volume effects play a
significant role. In this work, we study the impact of such effects on the
equation of state of pure Yang-Mills theory at low temperatures, comparing the
predictions of the statistical model with lattice results. In particular, we
present a detailed analysis of the SU(2) and SU(3) Yang-Mills theories: we find
that, for both of them, the best fits to the equilibrium thermodynamic
quantities are obtained when one assumes that the volume of different glueball
states is inversely proportional to their mass. The implications of these
findings for QCD are discussed.
