Robert Kao

We derive the expressions for the one-point energy correlator (OPEC) in deep inelastic scattering in the high-energy (small- x ) limit within the Color Glass Condensate (CGC) framework. The OPEC is computed as a function of the angle between the energy flow and the target proton or nucleus, enabling a systematic exploration of different momentum scales in the scattering process. Owing to the momentum sum rule, the dependence on fragmentation functions cancels, leaving the dipole amplitude as the only nonperturbative input. As a result, the OPEC provides a sensitive and promising probe of gluon saturation dynamics at small x . We present numerical results for representative kinematic configurations relevant to the future Electron-Ion Collider, demonstrating sizable nuclear suppression effects within the CGC framework and highlighting the consistency of this observable with predictions from gluon saturation.

We study the transverse energy-energy correlator (TEEC) observable in photon-hadron and photon-jet production in p + p and p + A collisions at small x . We derive the relevant expressions in the high-energy limit of the scattering where the dipole picture is applicable and show how the dependence on the fragmentation function of the hadron cancels due to the momentum-sum rule. The nonperturbative scattering with the target nucleus is expressed in terms of the dipole amplitude, which also describes nonlinear gluon saturation effects. The TEEC observable is computed in the Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) kinematics, and we show that it can be sensitive to the dipole amplitude, making it a potentially good observable for studying saturation effects.