scholarly journals Angular correlations in pA collisions from CGC: multiplicity and mean transverse momentum dependence of $$v_2$$

2021 ◽  
Vol 81 (7) ◽  
Author(s):  
Tolga Altinoluk ◽  
Néstor Armesto ◽  
Alex Kovner ◽  
Michael Lublinsky ◽  
Vladimir V. Skokov

AbstractWithin the dense-dilute Color Glass Condensate approach, and using the Golec–Biernat–Wuesthoff model for the dipole scattering amplitude, we calculate $$v_2^2$$ v 2 2 as well as the correlations between $$v_2^2$$ v 2 2 and both the total multiplicity and the mean transverse momentum of produced particles. We find that the correlations are generally very small consistent with the observations. We note an interesting sharp change in the value of $$v^2_2$$ v 2 2 as well as of its correlations as a function of the width of the transverse momentum bin. This crossover is associated with the change from Bose enhancement dominance of the correlation for narrow bin to HBT dominated correlations for larger bin width.

Author(s):  
JAMAL JALILIAN-MARIAN

At high energy (small x) n-point coorelators of Wilson lines appear in calculation of physical observables. The energy dependence of these observables is determined by the solution of the evolution equations these correlators satisfy. The most common correlator is the two-point function, the imaginary part of the forward scattering amplitude of a quark anti-quark dipole scattering on a target. This appears in structure functions in DIS as well as single inclusive hadron production in proton-nucleus collisions. Higher point correlators of Wilson lines appear in less inclusive processes, such as two-hadron angular and rapidity correlations and satisfy the Balitski-JIMWLK evolution equation. Here we derive the evolution equation satisfied by the six point correlator of Wilson lines which appears in di-hadron angular correlations in proton-nucleus collisions at high energy.


Author(s):  
Pedro Agostini ◽  
Tolga Altinoluk ◽  
Néstor Armesto

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 non-eikonal 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.


2018 ◽  
Vol 27 (05) ◽  
pp. 1830003 ◽  
Author(s):  
Elena Petreska

In this paper, we review recent progress in the description of unpolarized transverse-momentum-dependent (TMD) gluon distributions at small [Formula: see text] in the color glass condensate (CGC) effective theory. We discuss the origin of the nonuniversality of TMD gluon distributions in the TMD factorization framework and in the CGC theory and the equivalence of the two approaches in their overlapping domain of validity. We show some applications of this equivalence, including recent results on the behavior of TMD gluon distributions at small [Formula: see text], and on the study of gluon saturation. We discuss recent advances in the unification of the TMD evolution and the nonlinear small-[Formula: see text] evolution of gluon distributions.


2000 ◽  
Vol 63 (10) ◽  
pp. 1831-1834 ◽  
Author(s):  
M. A. Braun ◽  
V. V. Vechernin

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