  We investigate the scattering of two scalar glueballs in pure YM theory,
using the well known dilaton potential. We perform the calculations considering
a glueball mass of about $m_G \approx 1.7$ GeV, as predicted by lattice QCD. We
begin with the tree-level theory, but the question about the presence of a
bound state needs a deeper study to be answered. Thus we unitarize the theory
through a self energy loop function consisting of a single subtraction at the
single glueball resonance pole. We show that this choice is inconsistent as it
leads to the emergence of a ghost-like state with negative norm. This problem
is related with the sign of the coefficient in the first order term of the
expansion of the reverse unitarized amplitude. We briefly discuss the solution
which consists of an additional subtraction in the loop function, as presented
in Eur.Phys.J.C 82 (2022) 5, 487.

High Energy Physics - Phenomenology