Particle Production at High Energy and Large Transverse Momentum - "The Hybrid Formalism" Revisited

TL;DR

This paper revisits the hybrid formalism for high-energy particle production, highlighting an additional inelastic scattering contribution that becomes significant at high momenta and energies, impacting saturation effect studies.

Contribution

It identifies an overlooked inelastic scattering contribution in the hybrid formalism, emphasizing its importance at high energies and momenta for saturation physics.

Findings

Extra inelastic scattering contribution identified in the formalism.

Contribution is negligible at very forward rapidities but significant at high energies.

Implication for saturation effects at high energies and momenta.

Abstract

We revisit the "`hybrid formalism"' for particle production used recently to study saturation effects in single hadron multiplicities at forward rapidities at RHIC and LHC. We point out that at leading twist there is an extra contribution to the formulae used so far, which corresponds to particle production via inelastic scattering of the projectile partons on the target fields. This contribution is expected to be small due to kinematics at very forward rapidities/very high transverse momenta, but should be significant at high momenta and very high energies. This contribution is expected to be most affected by saturation effects and is therefore an interesting object of study in the context of possible onset of saturation at high energies.