Probing the Color Glass Condensate in $pp$ collisions at forward rapidities and very low transverse momenta

Abstract

The description of the hadron production at very forward rapidities and low transverse momentum is usually made using phenomenological models based on nonperturbative physics. However, at high energies and large rapidities the wave function of one of the projectiles is probed at very small Bjorken $x$, being characterized by a large number of gluons. In this kinematical regime, a new state of matter - the Color Glass Condensate (CGC) - is expected to be formed. One the main characteristics of such system is the presence of a new dynamical momentum scale, the saturation scale $Q_s$, which can assume values very larger than the QCD confinement scale ${\Lambda }_{QCD}$ and give the scale of the running coupling constant. In this paper we assume that in particular kinematical region probed by LHC forward (LHCf) experiment the saturation scale can be considered the hard momentum scale present in the process and calculate the forward neutral pion production at very low-$p_T$ using a perturbative approach. We demonstrate that the CGC formalism is able to successfully describe the LHCf data, which can be considered as a compelling indication of the presence of non-linear QCD effects at LHC energies.

7 pages, 2 figures. Improved version published in Nuclear Physics A. arXiv admin note: text overlap with arXiv:0907.3416

References in corpus (19)

• The Color Glass Condensate
• NLO evolution of color dipoles
• Quark contribution to the small-$x$ evolution of color dipole
• Triumvirate of Running Couplings in Small-x Evolution
• Determination of fragmentation functions and their uncertainties
• Non-linear QCD meets data: A global analysis of lepton-proton scattering with running coupling BK evolution
• Solving The High Energy Evolution Equation Including Running Coupling Corrections
• CGC predictions for p+Pb collisions at the LHC
• Single Inclusive Hadron Production at RHIC and the LHC from the Color Glass Condensate
• Particle Production at High Energy and Large Transverse Momentum - "The Hybrid Formalism" Revisited
• Quark loop contribution to BFKL evolution: Running coupling and leading-N_f NLO intercept
• Geometric scaling in diffractive deep inelastic scattering
• Saturation physics at HERA and RHIC: An unified description
• Geometric Scaling at RHIC and LHC
• Hadron production in pA collisions at the LHC from the Color Glass Condensate
• HERA-data in the light of small x evolution with state of the art NLO input
• Forward gluon production in hadron-hadron scattering with Pomeron loops
• Hadron and Photon Production in the Forward Region at RHIC and LHC
• Proton and anti-proton production in the forward region of d+Au collisions at RHIC from the color glass condensate

Cited by in corpus (6)

• Next-to-leading order Balitsky-Kovchegov equation beyond large $N_{\mathrm{c}}$
• Saturation and forward jets in proton-lead collisions at the LHC
• Baryon stopping in the Color Glass Condensate formalism: A phenomenological study
• On the rapidity dependence of the average transverse momentum in hadronic collisions
• Forward Hadron Productions in high energy pp collisions from a Monte-Carlo generator for Color Glass Condensate
• Relativistic diffusion model for hadron production in p-Pb collisions at the LHC