An Estimate of Twist-Four Contributions at Small x and Low Q^2

TL;DR

This paper investigates gluonic twist-four corrections to the deep inelastic structure function F_2 at small x and low Q^2, using double logarithmic approximation and exploring their impact relative to leading-twist contributions.

Contribution

It provides the first detailed estimate of gluonic twist-four effects at small x and Q^2, connecting them with diffractive dissociation and analyzing their magnitude for different input distributions.

Findings

Twist-four corrections can be significant at small x and low Q^2.

The size of twist-four effects varies with input distributions.

Connection established between twist-four corrections and diffractive dissociation processes.

Abstract

We present a first study of gluonic twist-four corrections to the deep inelastic structure function F_2 at small x and small Q^2. The calculations are based upon the double logarithmic approximation of the coupled twist-four evolution equations of the gluonic twist-four operators that are expected to be dominant at small x. We first review the analytical results which are presently available and define the framework of our calculation. In the second part we discuss the connection with DIS diffractive dissociation which can be used to estimate the size of some of the twist-four corrections. In the final part we show, for three different choices of the input distributions, the relative magnitude of the leading-twist and the twist-four contributions.