A zero-dimensional model for high-energy scattering in QCD

作者：Blaizot J P; Iancu E^*; Triantafyllopoulos D N

来源：Nuclear Physics A, 2007, 784: 227-258.

DOI：10.1016/j.nuclphysa.2006.11.127

We investigate a zero-dimensional toy model originally introduced by Mueller and Salant [A.H. Mueller, G.P. Salam, Nucl. Phys. B 475 (1996) 293] which mimics high-energy scattering in QCD in the presence of both gluon saturation and gluon number fluctuations, and hence of pomeron loops. Unlike other toy models of the reaction-diffusion type, the model studied in this paper is consistent with boost invariance and, related to that, it exhibits a mechanism for particle saturation close to that of the JIMWLK equation in QCD, namely the saturation of the emission rate due to high-density effects. Within this model, we establish the dominant high-energy behavior of the S-matrix element < S-n > for the scattering between a target obtained by evolving one particle and a projectile made with exactly n particles. Remarkably, we find that all such matrix elements approach the black disk limit S = 0 at high rapidity Y, with the same exponential law: < S-n > similar to exp(-Y) for all values of n. This is so because the S-matrix is dominated by rare target configurations which involve only few particles. We also find that the bulk distribution for a saturated system is of the Poisson type.

• 出版日期2007-3-1
• 单位中国地震局