This paper is devoted to proving that, in QCD, the lightest glueball state must be the scalar with $J^{\mathrm{PC}}{=0\mathrm{}}^{++}$. The proof relies upon the positivity of the path integral measure in Euclidean space and the fact that interpolating fields for all spins can be bounded by powers of the scalar glueball operator. The problem presented by the presence of vacuum condensates is circumvented by considering the time and space evolution of the propagators.

• Received 4 March 1996

DOI:https://doi.org/10.1103/PhysRevLett.77.2622