The High-energy Proton - Nuclear Reaction N ~ *,

The investigation of excited baryons is very important in understanding the internal structure of baryon and the strong interaction in the nonperturbative quantum chromodynamics (NPQCD) regime. However, there was not much progress on the baryon spectroscopy data since the late 1970's. Our present knowledge on excited baryons comes mostly from the partial wave analysis (PWA) of the irN and KN scattering data before 1980. There are many ambiguous issues in this field.In this paper , which is about p + A â†' p' + A' + Ï€ reaction process , exciting the N* (1440) in the projectile of protron mediated by an isoscalar (cr) exchange , we continued to work in the framework of effective theory . But we study the roper N*(1440) excitation in the A(p,p')Ï€A' reaction based upon the theory of relativity . So that we can extract the relevant knowledge of the excited nucleon state that serves as an intermediate state in such a process. The theoretical formularies of invary amplitude , the form factor of nucleons A and differential cross sections are given about this process. There are charge distribution of the nucleons A which is not a point, thus , in our invariant amplitude the form factor of nucleons A will come spontaneously , the cross section will be much imfluenced by the form factor . By calcaulating , it is shown that the form factor is very sensitive to the section when the momentum transfer is bigger . Generally speaking , in highly nenegy collisin the distort factor dependingon the degree of final particals can be regard as forward direction , the distort factor will weight down the cross section wholely. Given a definite beam nenegy 2 - 3Gev we could calculate the possible cross section of iV*(1440) excitation on projectile proton in this the reaction , which the target is 12C, 4He and 40Ca respectively . We could get all kinds of information about final particles. With calculating one can observe the N*(1440) resonance peak obviously in the invariant mass spectrum of Ï€N system , and in daliz plots the event number distribution is density, there are no such phenomenons in other composed systems .All of these things we have got will be helpful to the imminent experimental detection. Although the data come from experiments has not obtain, yet, the preliminary result has provided us certain knowledge on the properties of the lower-lying iV*states.