The Large N Limit from the Lattice

A numerical study of the string tension and of the masses of the lowest-lying glueballs is performed in SU(N) gauge theories for 2 ≤ N ≤ 8 in D = 3 + 1 and 2 ≤ N ≤ 6 in D = 2 + 1. It is shown that for the string tension a smooth N → ∞ limit exists that depends only on the ’t Hooft coupling λ = g²N. An extrapolation of the masses of the lightest glueballs to N = ∞ using a power series in 1/N² shows that the leading correction to the infinite N value accounts for finite N effects for N at least as small as 3 and all the way down to N = 2 in many cases. k-String tension ratios and possible issues connected with correlation functions at large N are also discussed.