The structure functions F_2^c and F_L^c in the framework of the k_T   factorization
  We present the perturbative parts of the structure functions F_2^c and F_L^c for a gluon target having nonzero transverse momentum squared at order \alpha _s. The results of the 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 HERA experimental data for F_2^c. The contribution from F_L^c structure function ranges 10\div30% of that of F_2^c at the HERA kinematical range. 
A. V. Kotikov (JINR, Dubna), A. V. Lipatov (MSU, Moscow), G. Parente   (Santiago de Compostela, Spain), N. P. Zotov (SINP, M...