Small x physics beyond eikonal approximation: an effective Hamiltonian approach

A bstract Understanding the spin structure of hadrons in small x regime is an important direction to unravel puzzle hadronic physics. To include degrees freedom requires going beyond usual eikonal approximation high energy QCD. We developed effective Hamiltonian approach study related observables using shockwave formalism. The small- incorporates both quark and gluon propagators background fields field induced interaction vertices up next-to-eikonal order. novel feature sub-eikonal interactions radiation inside shockwave. Its relation chromo-electrically polarized Wilson line correlator established helicity evolution longitudinal double-spin asymmetry for production.