Eur. Phys. J. C 27, 219-228 (2003)
DOI: 10.1140/epjc/s2002-01107-1

The contribution of off-shell gluons to the longitudinal structure function F_L

A.V. Kotikov¹, A.V. Lipatov² and N.P. Zotov<sup>3

1</sup>  Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980 Dubna, Russia
²  Department of Physics, Lomonosov Moscow State University, 119899 Moscow, Russia
³  Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, 119992 Moscow, Russia

(Received: 21 August 2002 / Revised version: 31 October 2002 Published online: 24 January 2003 )

Abstract
We present the results for the structure function F_L for a gluon target having a non-zero transverse momentum square at order . The results of a double convolution (with respect to the Bjorken variable x and the transverse momentum) of the perturbative part and the unintegrated gluon densities are compared with recent experimental data for F_L at low x values and with the predictions of other approaches.

© Società Italiana di Fisica, Springer-Verlag 2003