High-energy Operator Product Expansion at sub-eikonal level

TL;DR

This paper extends the high-energy Operator Product Expansion to the sub-eikonal level, deriving impact factors, defining new distribution functions, and establishing evolution equations for polarized and unpolarized structure functions.

Contribution

It provides a rigorous extension of the high-energy OPE to sub-eikonal accuracy, including impact factors and evolution equations for structure functions.

Findings

Derived impact factors for polarized and unpolarized structure functions

Defined new distribution functions at sub-eikonal level

Established evolution equations for structure functions

Abstract

The high energy Operator Product Expansion for the product of two electromagnetic currents is extended to the sub-eikonal level in a rigorous way. I calculate the impact factors for polarized and unpolarized structure functions, define new distribution functions, and derive the evolution equations for unpolarized and polarized structure functions in the flavor singlet and non-singlet case.