Nuclear structure functions and cross-sections for heavy flavour production
in lepton-nucleus collisions are investigated in the low x region accessible
now or in the near future. The scattering on a heavy nucleus is described by
the sum of fan diagrams of BFKL pomerons, which is exact in the high-colour
limit. The initial condition for the evolution at x=0.01 is taken from a
saturation model, which reproduces the experimental data on the proton. The A
dependence of the structure functions is well described by a power factor
Aα, with α reaching values as low as 1/2 at extremely low x.
The total cross-sections for heavy flavour production reach values of the order
of mb, and the corresponding transverse momentum distributions are sizeable up
to transverse momenta larger than the initial large scale Q2+4mf2​​.Comment: LaTeX2e, 16 pages, 6 eps figures included using epsfig; final
version, some comments added, results and conclusions unchange