Low-x improved TMD approach to the lepto- and hadroproduction of a heavy-quark pair

We compute the differential yield for quark anti-quark dijet production in high-energy electron-proton and electron-nucleus collisions at small x as a function of the relative momentum P⊥ and momentum imbalance k⊥ of the dijet system for different photon virtualities Q2, and study the elliptic and quadrangular anisotropies in the relative angle between P⊥ and k⊥. We review and extend the analysis in [1], which compared the results of the Color Glass Condensate (CGC) with those obtained using the transverse momentum dependent (TMD) framework. In particular, we include in our comparison the improved TMD (ITMD) framework, which resums kinematic power corrections of the ratio k⊥ over the hard scale Q⊥. By comparing ITMD and CGC results we are able to isolate genuine higher saturation contributions in the ratio Qs/Q⊥ which are resummed only in the CGC. These saturation contributions are in addition to those in the Weizsäcker-Williams gluon TMD that appear in powers of Qs/k⊥. We provide numerical estimates of these contributions for inclusive dijet production at the future Electron-Ion Collider, and identify kinematic windows where they can become relevant in the measurement of dijet and dihadron azimuthal correlations. We argue that such measurements will allow the detailed experimental study of both kinematic power corrections and genuine gluon saturation effects.

“…While this work was in progress, the hard ITMD factors were computed independently in[91]. We have verified that both results are equivalent 10.…”

mentioning

confidence: 67%

“…It is illustrative to consider two interesting limits: the so-called ITMD * limit [91], and photo-production limit Q 2 → 0.…”

Section: Jhep09(2021)178mentioning

confidence: 99%

“…The hard factors in the ITMD * scheme can be obtained in a diagrammatic approach with off-shell gluons [80], and they can be obtained from our results by the following projection [91]:…”

Section: Jhep09(2021)178mentioning

confidence: 99%

Section: Jhep09(2021)178mentioning

confidence: 99%

See 2 more Smart Citations

The importance of kinematic twists and genuine saturation effects in dijet production at the Electron-Ion Collider

Boussarie

Mäntysaari

Salazar

et al. 2021

“…Recent numerical studies at leading order [55,[93][94][95][96] suggest the importance of kinematic power [97][98][99] and genuine saturation effects [100][101][102] at kinematics accessible at current and future colliders.…”

Section: Jhep11(2021)222mentioning

confidence: 99%

Dijet impact factor in DIS at next-to-leading order in the Color Glass Condensate

Caucal

Salazar

Venugopalan

2021

We compute the next-to-leading order impact factor for inclusive dijet production in deeply inelastic electron-nucleus scattering at small xBj. Our computation, performed in the framework of the Color Glass Condensate effective field theory, includes all real and virtual contributions in the gluon shock wave background of all-twist lightlike Wilson line correlators. We demonstrate explicitly that the rapidity evolution of these correlators, to leading logarithmic accuracy, is described by the JIMWLK Hamiltonian. When combined with the next-to-leading order JIMWLK Hamiltonian, our results for the impact factor improve the accuracy of the inclusive dijet cross-section to $$ \mathcal{O} $$ O ($$ {\alpha}_s^2 $$ α s 2 ln(xf/xBj)), where xf is a rapidity factorization scale. These results are an essential ingredient in assessing the discovery potential of inclusive dijets to uncover the physics of gluon saturation at the Electron-Ion Collider.

Rapidity-only TMD factorization at one loop

Balitsky

2023

Typically, a production of a particle with a small transverse momentum in hadron-hadron collisions is described by CSS-based TMD factorization at moderate Bjorken xB ~ 1 and by kT-factorization at small xB. A uniform description valid for all xB is provided by rapidity-only TMD factorization developed in a series of recent papers at the tree level. In this paper the rapidity-only TMD factorization for particle production by gluon fusion is extended to the one-loop level.