In order to use the quark-parton model, i.e. PDF, scattered quarks
have to be (quasi-)free during the interaction. However, in the region
of low Mhad values, there is a non-negligible contribution from the
final state interaction between the scattered quark and the remnant of
the proton. In this case, the factorization of hard and soft
processes does not hold, so that one cannot simulate the process
using the quark-parton model.
Actually, in the region of Mhad<5GeV, there are significant
contributions from the Delta resonance production, light vector-meson
production and some other diffractive processes, which are included
in the simulation of the quasi-elastic process using SOPHIA and the parameterizations
of ALLM and Brasse et al.
Comments to Tetsuo ABE (firstname.lastname@example.org)
Last updated on Oct. 5, 2001