Speaker
Description
For dijet production in deeply inelastic scattering, photon-quark scattering is important at large x, while photon-gluon fusion becomes important toward smaller x. In the large-x regime, the energetic parton
undergoes multiple scattering and gluon radiation in a large nucleus (jet quenching), where LPM interference can be observed [Y. Y. Zhang and X. N. Wang 2022]. In the small-x regime, the virtual photon
splits into a q¯
q dipole, which scatters off the Lorentz-contracted nuclear color field; saturation effects become important. There are ongoing efforts to bridge these two regimes from both directions. From
small x to large x, next-to-eikonal (NEik) corrections to the Color Glass Condensate (CGC) framework go beyond the shock-wave limit. In particular, DIS dijet production was calculated at NEik accuracy in
[Altinoluk et al. 2023]. From large x to small x, it was shown in [Fu et al. 2025] that, by adding sub-eikonal momentum phases, CGC can match the high-twist (HT) expansion formalism for direct-photon
pA production. In this work, we calculate the nuclear modification of photon-gluon fusion, i.e., the leading-order (LO) twist-4 photon-gluon channel within the generalized high-twist approach. Combining
LO twist-4 photon-quark and photon-gluon contributions, our numerical results show that the photon-gluon channel gives the dominant nuclear modification at intermediate x.
