Proton and deuteron F_2 structure function at low Q^2

Abstract

Measurements of the proton and deuteron F2 structure functions are presented. The data, taken at Jefferson Lab Hall C, span the four-momentum transfer range 0.06 < Q^2 < 2.8 GeV^2 and Bjorken x values from 0.009 to 0.45, thus extending the knowledge of F_2 to low values of Q^2 at low x. Next-to-next-to-leading-order calculations using recent parton distribution functions start to deviate from the data for Q^2 < 2 GeV^2 at the low and high x values. Down to the lowest value of Q^2, the structure function is in good agreement with a parametrization of F_2 based on data that have been taken at much higher values of Q^2 or much lower values of x, and which are constrained by data at the photon point. The ratio of the deuteron and proton structure functions at low x remains well described by a logarithmic dependence on Q^2 at low Q^2.

Files

Additional details