Multiparticle production in proton–nucleus collisions beyond eikonal accuracy

Pedro Agostini; Tolga Altinoluk; Néstor Armesto; Fabio Dominguez; José Guilherme Milhano

doi:10.1140/epjc/s10052-022-10962-1

2023 Impact factor 4.2

Particles and Fields

Open Access

Eur. Phys. J. C (2022) 82: 1001
https://doi.org/10.1140/epjc/s10052-022-10962-1

Regular Article - Theoretical Physics

Multiparticle production in proton–nucleus collisions beyond eikonal accuracy

Pedro Agostini¹, Tolga Altinoluk², Néstor Armesto¹^c, Fabio Dominguez¹ and José Guilherme Milhano³^,4

¹ Departamento de Física de Partículas and IGFAE, Universidade de Santiago de Compostela, 15782, Santiago de Compostela, Galicia, Spain
² Theoretical Physics Division, National Centre for Nuclear Research, Pasteura 7, 02-093, Warsaw, Poland
³ Laboratório de Instrumentação e Física Experimental de Partículas (LIP), Av. Professor Gama Pinto 2, 1649-003, Lisbon, Portugal
⁴ Departamento de Física, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1609-001, Lisbon, Portugal

^c nestor.armesto@usc.es

Received: 5 August 2022
Accepted: 26 October 2022
Published online: 7 November 2022

Abstract

We study the effects on multigluon production at mid-rapidity in the Color Glass Condensate of the non-eikonal corrections that stem from relaxing the shockwave approximation and giving the target a finite size. We extend previous works performed in the dilute-dilute approximation suitable for proton–proton collisions, to the dilute-dense one applicable to proton–nucleus. We employ the McLerran–Venugopalan model for the projectile averages. For the target averages, we use the Golec-Biernat–Wüsthoff model and restrict to the leading contributions in overlap area that allow a factorization of ensembles of Wilson lines into products of dipoles. We make the connection with the jet quenching formalism and compare with previous results in the literature, providing a parametrization of the so-called decorated dipoles. We show that the non-eikonal effects on single inclusive particle production, contrary to what happens in jet quenching, are only sizable, of a few percent, for modest energies $\sqrt{s_{NN}} \leq 100$ $\sqrt{s_{NN}}\le 100$ GeV and central rapidities. On the other hand, we find that the effects on double inclusive gluon production are larger for the same kinematics. We show that, as found previously in the dilute-dilute situation, non-eikonal corrections break the accidental symmetry in the CGC, allowing for the existence of non-vanishing odd azimuthal harmonics.

© The Author(s) 2022

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