Analytic Expression for the Joint x and Q^2 Dependences of the Structure Functions of Deep Inelastic Scattering

摘要

We obtain a good analytic fit to the joint Bjorken-x and Q^2 dependences ofZEUS data on the deep inelastic structure function F_2(x, Q^2). At fixedvirtuality Q^2, as we showed previously, our expression is an expansion inpowers of log (1/x) that satisfies the Froissart bound. Here we show that foreach x, the Q^2 dependence of the data is well described by an expansion inpowers of log Q^2. The resulting analytic expression allows us to predict thelogarithmic derivatives {({\partial}^n F_2^p/{{(\partial\ln Q^2}})^n)}_x for n= 1,2 and to compare the results successfully with other data. We extrapolatethe proton structure function F_2^p(x,Q^2) to the very large Q^2 and the verysmall x regions that are inaccessible to present day experiments and contrastour expectations with those of conventional global fits of parton distributionfunctions.