Final-state interaction in semi-inclusive DIS off nucleiC. Ciofi degli Atti1 and B.Z. Kopeliovich2, 3
1 Department of Physics, University of Perugia, and INFN, Sezione di Perugia, via A. Pascoli, Perugia, I-06100, Italy
2 Max-Planck-Institut für Kernphysik, Postfach 103980, 69029 Heidelberg, Germany
3 Institut für Theoretische Physik der Universität, 93040 Regensburg, Germany
(Received: 28 June 2002 / Revised version: 6 October 2002 / Published online: 5 May 2003)
The Final-State Interaction (FSI) in Deep-Inelastic Scattering (DIS) of leptons off a nucleus A, due to the propagation of the struck nucleon debris and its hadronization in the nuclear environment is considered. The effective cross-section of such a partonic system with the nucleons of the medium and its time dependence are estimated, for different values of the Bjorken scaling variable, on the basis of a model which takes into account both the production of hadrons due to the breaking of the color string, which is formed after a quark is knocked out off a bound nucleon, as well as the production of hadrons originating from gluon radiation. It is shown that the interaction, the evolution and the hadronization of the partonic system in the nuclear environment can be thoroughly investigated by a new type of semi-inclusive process, denoted A(e,e'(A-1))X, in which the scattered lepton is detected in coincidence with a heavy nuclear fragment, namely a nucleus ( A-1) in low energy and momentum states. As a matter of fact, if the FSI is disregarded, the momentum distribution of ( A-1) is directly related to the momentum distribution of the nucleon before absorption, i.e. the same quantity which appears in the conventional A(e,e'N)X process, where N denotes a nucleon. The rescattering of the struck nucleon debris with the medium damps and distorts the momentum distributions of ( A-1) in a way which is very sensitive to the details of the effective cross-section of the debris with the nucleons of the medium. The total cross-section of the process A(e,e'(A-1))X on , , and , related to the probability that after a target nucleon experiences a DIS process, the recoiling ( A-1) nucleus remains intact in spite of the strong FSI, is evaluated, and the distorted momentum distribution of the recoiling ( A-1) system is obtained. It is shown that both quantities are very sensitive to the details of the early stage of hadronization of the nucleon debris in the nuclear medium.
24.85.+p - Quarks, gluons, and QCD in nuclei and nuclear processes.
25.10.+s - Nuclear reactions involving few-nucleon systems.
25.30.Dh - Inelastic electron scattering to specific states.
25.30.Fj - Inelastic electron scattering to continuum.
© Società Italiana di Fisica, Springer-Verlag 2003