Initial gluon multiplicity in heavy-ion collisions

The initial gluon multiplicity per unit area per unit rapidity, dN/L-2/d et a, in high energy nuclear collisions, is equal to f(N)(g(2)muL) (g(2)mu)(2) /g(2), With mu (2) proportional to the gluon density per unit area of the c olliding nuclei. For an SU(2) gauge theory, we compute f(N)(g(2)muL) = 0.14 +/- 0.01 for a wide range in g(2)muL. Extrapolating to SU(3). we predict d N/L-2/d eta for values of g(2)muL relevant to the Relativistic Heavy ion Co llider and the Large Hadron Collider. We compute the initial gluon transver se momentum distribution, dN/L-2/d(2)k(perpendicular to), and show it to be well behaved at low k(perpendicular to).