Glueball Regge trajectories and the pomeron: a lattice study

We perform lattice calculations of the lightest J=0,2,4,6 glueball masses in the D=3+1 SU(3) gauge theory and extrapolate to the continuum limit. Assuming that these masses lie on linear Regge trajectories we find a leading glueball trajectory α(t)=0.93(24)+0.28(2)αR′t, where αR′≃0.9 GeV−2 is the slope of the usual mesonic Regge trajectory. This glueball trajectory has an intercept and slope similar to that of the pomeron trajectory. We contrast this with the situation in D=2+1 where the leading glueball Regge trajectory is found to have too small an intercept to be important for high-energy cross sections. We interpret the observed states and trajectories in terms of open and closed string models of glueballs. We discuss the large-N limit and perform an SU(8) calculation that hints at new states based on closed strings in higher representations.