  Let G be a semisimple Lie group without compact factor and $\Gamma$ < G a
torsion-free, cocompact, irreducible lattice. According to Selberg, periodic
orbits of regular Weyl chamber flows live on tori. We prove that these periodic
tori equidistribute exponentially fast towards the quotient of the Haar
measure. From the equidistribution formula, we deduce a higher rank prime
geodesic theorem.
