The topological susceptibility in the large-N limit of SU(N) Yang-Mills theory

We compute the topological susceptibility of the SU (N) Yang-Mills theory in the large-N limit with a percent level accuracy. This is achieved by measuring the gradient-flow definition of the susceptibility at three values of the lattice spacing for N = 3 , 4 , 5 , 6. Thanks to this coverage of parameter space, we can extrapolate the results to the large-N and continuum limits with confidence. Open boundary conditions are instrumental to make simulations feasible on the finer lattices at the larger N.