J. Breitweg et al., MEASUREMENT OF THE PROTON STRUCTURE-FUNCTION F-2 AND SIGMA(GAMMA-ASTERISK-P)(TOT) AT LOW Q(2) AND VERY-LOW-X AT HERA, Physics letters. Section B, 407(3-4), 1997, pp. 432-448
A small electromagnetic sampling calorimeter, installed in the ZEUS ex
periment in 1995, significantly enhanced the acceptance for very low x
and low Q(2) inelastic neutral current scattering, e(+)p --> e(+)X, a
t HERA. A measurement of the proton structure function F-2 and the tot
al virtual photon-proton (gammap) cross-section is presented for 0.11
less than or equal to Q(2) less than or equal to 0.65 GeV2 and 2 x 10
(-6) less than or equal to x less than or equal to 6 x 10(-5), corresp
onding to a range in the gammap c.m. energy of 100 less than or equal
to W less than or equal to 230 GeV. Comparisons with various models a
re also presented. (C) 1997 Published by Elsevier Science B.V.