Diffractive Structure Functions from the H1 and ZEUS Experiments at HERA

TL;DR

This paper reports precise measurements of diffractive structure functions at HERA, leading to improved diffractive parton distribution functions and first direct measurement of the longitudinal diffractive structure function.

Contribution

It provides high-precision diffractive structure function data, refined DPDFs with reduced uncertainties, and the first direct measurement of $F^D_L$, advancing understanding of diffraction in DIS.

Findings

High-precision diffractive structure function measurements.

Refined diffractive parton distribution functions with reduced uncertainties.

First direct measurement of the longitudinal diffractive structure function.

Abstract

The cross section of inclusive diffractive process ep -> eXp was measured within a wide kinematic range in the H1 and ZEUS experiments at HERA. Results obtained by different experiments and methods are compatible within measurement uncertainties. The measurements were subjected to DGLAP next-to-leading order QCD global fits and the diffractive parton distribution functions (DPDFs) of the proton were determined with noticeably reduced uncertainties due to very high precision of the data. The gluon density precision was much improved in fits which also included data on dijet production in diffractive DIS. Predictions based on the determined DPDFs are in agreement with the measured inclusive cross-section of diffractive dijet photoproduction and charm production in diffractive DIS at HERA. The longitudinal diffractive structure function $F^D_L$ was measured directly for the first time.