Quark jets scattering from a gluon field: from saturation to high $p_t$

Abstract

We continue our studies of possible generalization of the Color Glass Condensate (CGC) effective theory of high energy QCD to include the high $p_t$ (or equivalently large $x$) QCD dynamics as proposed in [JJM-elastic]. Here we consider scattering of a quark from both the small and large $x$ gluon degrees of freedom in a proton or nucleus target and derive the full scattering amplitude by including the interactions between the small and large $x$ gluons of the target. We thus generalize the standard eikonal approximation for parton scattering which can now be deflected by a large angle (and therefore have large $p_t$) and also lose a significant fraction of its longitudinal momentum (unlike the eikonal approximation). The corresponding production cross section can thus serve as the starting point toward derivation of a general evolution equation that would contain DGLAP evolution equation at large $Q^2$ and the JIMWLK evolution equation at small $x$. This amplitude can also be used to construct the quark Feynman propagator which is the first ingredient needed to generalize the Color Glass Condensate (CGC) effective theory of high energy QCD to include the high $p_t$ dynamics. We outline how it can be used to compute observables in the large $x$ (high $p_t$) kinematic region where the standard Color Glass Condensate formalism breaks down.

17 pages, 9 figures

References in corpus (11)

• The Color Glass Condensate
• Next-to-eikonal corrections in the CGC: gluon production and spin asymmetries in pA collisions
• CGC factorization for forward particle production in proton-nucleus collisions at next-to-leading order
• Small-$x$ Helicity Evolution: an Operator Treatment
• Next-to-leading order forward hadron production in the small-$x$ regime: rapidity factorization
• Two-gluon correlations and initial conditions for small-x evolution
• Elastic scattering of a quark from a color field: longitudinal momentum exchange
• Forward dijets in high-energy collisions: evolution of QCD n-point functions beyond the dipole approximation
• TMD splitting functions in kT factorization: the real contribution to the gluon-to-gluon splitting
• Transverse momentum dependent splitting functions at work: quark-to-gluon splitting
• Saturation in inclusive production beyond leading logarithm accuracy

Cited by in corpus (18)

• Quarks at next-to-eikonal accuracy in the CGC I: Forward quark-nucleus scattering
• Helicity-dependent extension of the McLerran-Venugopalan model
• Quark and Gluon Helicity Evolution at Small $x$: Revised and Updated
• Quark and scalar propagators at next-to-eikonal accuracy in the CGC through a dynamical background gluon field
• Rapidity loss, spin and angular asymmetries in scattering of a quark from color field of a proton (nucleus)
• DIS dijet production at next-to-eikonal accuracy in the CGC
• Single Inclusive Hadron Production in DIS at Small $x$: Next to Leading Order Corrections
• Analytic Solution for the Revised Helicity Evolution at Small $x$ and Large $N_c$: New Resummed Gluon-Gluon Polarized Anomalous Dimension and Intercept
• Ultrarelativistic quark-nucleus scattering in a light-front Hamiltonian approach
• Single Inclusive Jet Production in $pA$ Collisions at NLO in the small-$x$ regime
• Gluon-mediated inclusive Deep Inelastic Scattering from Regge to Bjorken kinematics
• Multiparticle production in proton-nucleus collisions beyond eikonal accuracy
• Helicity Evolution at Small $x$: Revised Asymptotic Results at Large $N_c\&N_f$
• Lensing Mechanism Meets Small-$x$ Physics: Single Transverse Spin Asymmetry in $p^{\uparrow }+p$ and $p^{\uparrow }+A$ Collisions
• Global analysis of polarized DIS & SIDIS data with improved small-$x$ helicity evolution
• Quark TMDs from back-to-back dijet production at forward rapidities in pA collisions beyond eikonal accuracy in the CGC
• Color Glass Condensate meets High Twist Expansion
• Parton model contributions as next-to-eikonal corrections to the dipole factorization of DIS and SIDIS at low $x_{Bj}$