Measurement of the proton structure function F_2 and #sigma#"#gamma#""*""p_t_o_t at low Q"2 and very low x at HERA

Abstract

A small electromagnetic sampling calorimeter, installed in the ZEUS experiment in 1995, significantly enhanced the acceptance for very low x and low Q"2 inelastic neutral current scattering, e"+p #-># e"+X,at HERA. A measurement of the proton structure function F_2 and the total virtual photon-proton (#gamma#"*p) cross-section is presented for 0.11#<=#Q"2#<=#0.65 GeV"2 and 2 x 10"-"6#<=#x#<=#6 x 10"-"5, corresponding to a range in the #gamma#"*p c.m. energy of 100#<=#W#<=#230 GeV. Comparisons with various models are also presented. (orig.)Available from FIZ Karlsruhe / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman