Proton and anti-proton production in the forward region of collisions at RHIC from the color glass condensate

Abstract

The power-law tail of high-p t π ± spectra observed in forward d+Au collisions at RHIC can be attributed to the power-law decrease of the dipole forward scattering amplitude appearing in the color glass condensate (CGC) approach. Forward particle production probes the small-x gluon distribution of the target nucleus where its anomalous dimension is rather flat (γ = 0.6-0.8) for moderately high p t ( 5 GeV), and where the leading-twist DGLAP approximation is not valid. In the same framework, we examine p andp production using baryon fragmentation functions parameterized in the Lund fragmentation scheme. This provides a good description of the forwardp spectrum while it underestimates the p data by as much as a factor of 2-3 at p t 4 GeV. Part of this anomalous baryon excess can be attributed to surviving constituent diquarks from the deuteron projectile. Thus, the contribution from diquark scattering may play an essential role for forward baryon formation.

Forward hadron productions in high energyppcollisions from a Monte-Carlo generator for color glass condensate

“…[22]. Fragmentation function extracted from the Lund string model [57] scaled by AKK fragmentation function [58] was used in the calculations.…”

Testing non-linear evolution with running coupling corrections in ep and pp collisions

“…In this case the cross section is expressed as a convolution of the standard parton distributions for the dilute projectile, the dipole-hadron scattering amplitude (which includes the high-density effects) and the parton fragmentation functions. Basically, assuming this generalized densedilute factorization, the minimum bias invariant yield for single-inclusive hadron production in hadron-hadron processes is described in the CGC formalism by [33,34,84]…”

“…Moreover, x F = p T √ s e y and the momentum fraction of the target partons is given by x 2 = x 1 e −2y (For details see e.g. [84]).…”

Hadron and photon production in the forward region at RHIC and LHC

“…Moreover, x F = p T √ s e y and the momentum fraction of the target partons is given by x 2 = x 1 e −2y (For details see e.g. [22]). …”

“…In ref. [22] the author discuss two alternatives to implement this calculation, which implies different values for the effective saturation scale Q 2 s in minimum bias collisions. In what follows we assume that Q 2 s = A 1/3 eff Q 2 0 (x 0 /x 2 ) λ , with A eff = 18.5 (20.0) for dAu (pP b) collisions, in order to compare our predictions with those obtained in refs.…”