Asymptotics of QCD traveling waves with fluctuations and running coupling effects

Abstract

Extending the Balitsky-Kovchegov (BK) equation independently to running coupling or to fluctuation effects due to pomeron loops is known to lead in both cases to qualitative changes of the traveling-wave asymptotic solutions. In this paper we study the extension of the forward BK equation, including both running coupling and fluctuations effects, extending the method developed for the fixed coupling case [1]. We derive the exact asymptotic behavior in rapidity of the probabilistic distribution of the saturation scale.

Single inclusive hadron production at RHIC and the LHC from the color glass condensate

“…While our results offer an additional indication for the presence of CGC effects in RHIC data, the interest now focuses mostly in calibrating the expectations for the Heavy Ion program at the LHC. Our predictions for the LHC rely on the most up-to-date tools within the CGC formalism (Pomeron-loop corrections have been looked at [51], but are only relevant at asymptotically large energies when the running coupling is included [52,53]) and will be useful to confirm the tentative conclusions reached at RHIC and to distinguish between alternative physical scenarios, like those proposed in [54,55] (a complete set of predictions stemming from different formalisms can be found in [50]), where the suppression of forward yields at RHIC is due to the non-eikonal propagation of the leading parton, resulting in energy loss in the forward region. Finally, the proper characterization of gluon production in the early stages (before thermalization) of Pb+Pb collisions at the LHC would serve as crucial input for studies of the medium produced in such collisions, such as hydrodynamic simulations or studies of jet quenching.…”

QCD traveling waves phenomenology revisited

“…Going beyond the LL approximation, the solutions of the BK equation at next-to-leading logarithmic (NLL) order have been also investigated [13][14][15][16][17]. In Ref.…”

“…The role played by the fluctuations effects (Pomeron loops) in the NLL BK solution was analyzed in Ref. [16]. The starting point is a Langevin equation for the forward dipole-target scattering amplitude, N (r, Y ), with a Gaussian white noise.…”

Extended geometric scaling from generalized traveling waves

“…for a stochastic (s)FKPP or (s)BK equation, which after all reflects a physical constraint relying on the finiteness and randomness of the number of gluons, predicts a strong violation of geometric scaling not seen on data. On the other hand, the same stochasticity applied to the running coupling case seems from indirect evidence either to preserve geometric scaling [10] or to delay its violation to much higher energy [11].…”