Evidence of strong higher twist effects in diffractive DIS at HERA at moderate Q2

TL;DR

This paper provides strong evidence for higher twist effects in diffractive deep inelastic scattering at HERA, showing that including twist 4 and 6 components improves data description at low Q2.

Contribution

It demonstrates the significance of higher twist effects in DDIS and incorporates twist components of the GBW saturation model into DGLAP fits for better data agreement.

Findings

Data show up to 100% excess over twist 2 NLO DGLAP at low Q2.

Including twist 4 and 6 components improves the fit to HERA data.

First strong evidence of higher twist effects in DIS at HERA.

Abstract

We study a twist decomposition of diffractive structure functions in the diffractive deep inelastic scattering (DDIS) at HERA. At low Q2 and at large energy the data exhibit a strong excess, up to about 100%, above the twist 2 NLO DGLAP description. The excess in consistent with higher twist effects. It is found, that complementing the DGLAP fit by twist 4 and 6 components of the GBW saturation model leads to a good description of data at low Q2. We conclude that the DDIS at HERA provides the first, strong evidence of higher twist effects in DIS.