Effect of non-eikonal corrections on azimuthal asymmetries in the color glass condensate

Abstract

We analyse the azimuthal structure of two gluon correlations in the Color Glass Condensate including those effects that result from relaxing the shockwave approximation for the target. Working in the Glasma graph approach suitable for collisions between dilute systems, we compute numerically the azimuthal distributions and show that both even and odd harmonics appear. We study their dependence on model parameters, energy of the collision, pseudorapidity and transverse momentum of the produced particles, and length of the target. While the contribution from noneikonal corrections vanishes with increasing collision energy and becomes negligible at the energies of the Large Hadron Collider, it is found to be sizeable up to top energies at the Relativistic Heavy Ion Collider.

Rapidity loss, spin, and angular asymmetries in the scattering of a quark from the color field of a proton or nucleus

“…This can be easily checked by considering the single (large x) gluon exchange limit of our results, analogous to quark antiquark scattering considered in Appendix A of the last listing of [14]. Furthermore, noneikonal corrections to high energy scattering at small x have been shown to generate angular asymmetries in particle production at small x [15]. Very similarly the large x corrections to eikonal scattering considered here result in angular asymmetries, with the important difference that the asymmetries generated in our formalism will be at higher transverse momenta than the standard small x results.…”

Quarks at next-to-eikonal accuracy in the CGC I: Forward quark-nucleus scattering

“…Later in [47,48], it was shown that in the weak field limit, the finite-width corrections can be interpreted as sub-eikonal corrections to the standard Lipatov vertex and multi gluon production cross section is computed with non-eikonal corrections for proton-proton collisions at mid-rapidity. The effects of non-eikonal corrections (due to finite width of the target) on two-particle correlations are studied in [49]. Apart from the aforementioned studies that focus on the finite-width corrections to gluon production at mid-rapidity to go beyond the eikonal accuracy, in [50][51][52][53][54][55][56] quark and gluon helicity distributions are derived at Next-to-Eikonal (NEik) order.…”

Mining for Gluon Saturation at Colliders

“…Relaxing this assumption is necessary to access the physics of polarized measurements [257][258][259][260][261][262][263][264][265][266]. Efforts are also being carried out to study the effect of sub-eikonal contributions to various unpolarized observables [267][268][269][270][271][272] with emphasis in non-trivial azimuthal correlations. These contributions might be relevant for precise EIC and RHIC phenomenology where the energies are much less compared to LHC or LHeC.…”