Holographic Pomeron and Entropy

Abstract

In dipole-dipole scattering at large rapidity \chi={\rm ln}(s/s_0), the induced instanton on the string worldsheet carries entropy S_k=2(\alpha_{Pk}-1)\chi with \alpha_{Pk}-1 the pomeron intercept for a dipole source of N-ality k. This stringy entropy is neither coherent nor thermal. We argue that it is released promptly over a time t_R\approx (b / \chi)^3 / (4 \alpha') with \alpha'/2 the pomeron slope and b the impact parameter. This stringy entropy may explain the 3/2 jump in the total charged multiplicities at about 10 participants reported over a wide range of collider energies by PHOBOS. We predict the charged multiplicities in pp, pA and AA collisions at LHC.