Pion physics in the Liege intranuclear cascade model
- SCK-CEN, Boeretang 200, B-2400 Mol (Belgium)
- University of Liege, Physics Department, allee du 6 Aou circumflex t 17, bat. B5, B-4000 Liege 1 (Belgium)
The implementation of {pi} production in the Liege intranuclear cascade model (INCL4) for spallation reactions is revisited to alleviate the overestimate of the {pi} yield. Three modifications are proposed for this purpose: a better {pi}N cross section at high energy, the introduction of a {pi} average potential, and the modification of the average mass of the {delta} resonance. The {pi} potential is determined from a global fit of a set of data bearing on {pi} production in proton-induced reactions, on {pi}-nucleus and absorption cross sections, and on proton production in {pi}-induced reactions. The resulting {pi} potential is poorly determined in the nuclear interior and agrees with the phenomenological optical-model potentials in the surface region. With these modifications, the predictions of the INCL4 model concerning {pi} production cross sections in proton-induced reactions are considerably improved. Predictions of the improved version for {pi}-nucleus reaction and absorption cross sections and for proton, residue, and fission cross sections in {pi}-induced reactions are also presented and shown to give reasonably good agreement. Neutron production and some aspects of fission in {pi}-induced reactions are also investigated and reasonably well predicted. Effects on the modifications on observables, which are not directly linked with {pi}'s, such as the neutron yield and the residue mass and charge spectra in proton-induced reactions are also investigated and shown to improve the description of these observable quantities. Several results on {pi} production and the relative insentivity to the {pi} potential in the nuclear interior are shown to be consistent with the fact that most {pi}'s are not produced in early collisions. Importance of rescattering in {pi} absorption on nuclei is also pointed out. A comparison is made with the so-called {delta}-hole model. Residual discrepancies are identified and are interpreted as due to the lack of {pi} interaction with two nucleons at low energy, to the neglect of quantum motion effects, and to a possible underestimate of rescattering.
- OSTI ID:
- 20864212
- Journal Information:
- Physical Review. C, Nuclear Physics, Vol. 74, Issue 6; Other Information: DOI: 10.1103/PhysRevC.74.064607; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2813
- Country of Publication:
- United States
- Language:
- English
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