May 22 – 26, 2023
IJCLab, Orsay (FRANCE)
Europe/Paris timezone

Weizsäcker-Williams TMD factorization at NLO for back-to-back inclusive dijets in DIS at small x

May 23, 2023, 11:25 AM
Auditorium Joliot Curie (IJCLab, Orsay (FRANCE))

Auditorium Joliot Curie

IJCLab, Orsay (FRANCE)

15, Rue G. Clemenceau 91405 Orsay Cedex FRANCE


Dr Paul Caucal (Subatech)


The ”tomography” of the proton and heavy nuclei, which refers to the three-dimensional imaging of elementary quarks and gluons in these QCD bound states, is one the primary goal of the future Electron-Ion Collider (EIC). Gluon tomography is mathematically encoded into the gluon Weizs̈acker-Williams (WW) transverse momentum dependent (TMD) distribution which, in light cone gauge, represents the light cone quantized number distribution of gluons as function of their transverse momenta in a proton or nucleus at small $x_{\rm Bj}$. A "golden process" to extract the gluon WW distribution is the inclusive production of a pair of back-to-back jets, or back-to-back hadrons, in deep inelastic electron-proton or electron-nucleus scattering (DIS).

In this talk, I will show that for dijets with relative transverse momenta $P_\perp$ and transverse momentum imbalance $q_\perp$, to leading power in $q_\perp/P_\perp$, the cross-section for longitudinally and transversely polarized virtual photons to NLO can be fully factorized into a product of a perturbative hard factor and the non-perturbative Weizsäcker-Williams TMD. This factorization formula is valid to all orders in $Q_s/q_\perp$ for $q_\perp, Q_s\ll P_\perp$, where $Q_s$ is the CGC saturation scale. The hard factor and the soft factor, which resums Sudakov double and single logs in $P_\perp/q_\perp$, are given by remarkably compact analytic expressions while the WW TMD satisfies a kinematically constrained JIMWLK renormalization group evolution in rapidity.

I will finally present results of a numerical study that explores the relative importance of gluon saturation, Sudakov effects and genuine $\mathcal{O}(\alpha_s)$ corrections on the inclusive back-to-back dijet cross-section in DIS at small $x_{\rm Bj}$.

[1] Caucal, Salazar, Schenke, Venugopalan, JHEP 11 (2022) 169, arXiv:2208.13872.
[1] Caucal, Salazar, Schenke, Stebel, Venugopalan, to appear.

Primary authors

Dr Paul Caucal (Subatech) Farid Salazar (UCLA/UCB/LBNL) Bjoern Schenke (Brookhaven National Lab) Tomasz Stebel (Institute of Theoretical Physics Jagiellonian University) Raju Venugopalan

Presentation materials