Structure Function Measurement at HERA

TL;DR

This paper reports on measurements of the proton structure function F_2 at HERA, showing a significant increase at low x and Q^2, consistent with QCD predictions, and discusses future measurement prospects.

Contribution

First measurement of F_2 at a wide range of Q^2 and x at HERA, confirming QCD evolution and the radiative origin of the low-x rise.

Findings

F_2 increases with decreasing x at all Q^2

Data agree with Next to Leading Order QCD fits

Supports radiative generation of low-x rise via DGLAP

Abstract

Preliminary results on a measurement of the proton structure function F_2 are reported for momentum transfers squared Q^2 between 1.5~GeV^2 and 5000 GeV^2 and for Bjorken x between 5.10^{-5} and 0.32 using data collected by the HERA experiments H1 and ZEUS in 1994. F_2 increases significantly with decreasing x, even in the lowest reachable Q^2 region. The data are well described by a Next to Leading Order QCD fit, and support within the present precision that the rise at low x within this Q^2 range is generated "radiatively" via the DGLAP evolution equations. Prospects for future structure function measurements at HERA are briefly mentioned.