Holographic Pomeron and Entropy

Abstract

In dipole-dipole scattering at large rapidity χ={\rm ln}(s/s_0), the induced instanton on the string worldsheet carries entropy S_k=2(α_{Pk}-1)χwith α_{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 / χ)^3 / (4 α') with α'/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.