Is overlapping double gluon bremsstrahlung in a quark-gluon plasma accurately described by the N_color = ∞ limit?

   Jets produced from colliding two heavy nuclei play an important role in understanding properties of the Quark Gluon Plasma. During their travel through the medium, high energy partons lose energy through splitting processes like bremsstrahlung and pair production, induced by elastic scatterings with the medium. In the high energy limit, these splitting processes are coherent over large distances and the underlying elastic scatterings can no longer be treated as quantum mechanically independent, leading to a suppression of the splitting rate known as the Landau-Pomeranchuk-Migdal effect. An important question is whether consecutive splittings are themselves quantum mechanically independent or instead overlap significantly. Previously, the overlap of splitting rates has been analyzed in the N_c = ∞ limit within the thick medium approximation. To see if such N_c = ∞ calculations apply to real QCD with N_c = 3, we calculate the next-to-leading order correction in 1/N_c to overlapping gluon double-splitting. I will report first results on whether the N_c = ∞ approximation to the differential rate of overlapping double bremsstrahlung of gluons is reliable, and in particular whether the correction is large or small compared to the naive expectation of 1/N_c² ∽ 10% for N_c = 3.