Faculty of Physics - University of Bucharest

UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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2024-11-22 2:24

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Conference: Bucharest University Faculty of Physics 2007 Meeting

Section: Nuclear and Elementary Particles Physics

Title:

Some comments on the nuclear fragmentation in proton-nucleu collisions at 8 GeV and 12 GeV

Authors:

Calin BESLIU*, Alexandru JIPA*, Vania COVLEA*, Oana RISTEA*, Marius CALIN*, Tiberiu ESANU*, Cristian BORDEIANU, Valentin GROSSU*, Valentin Cornel PAVEL*, Adrian SCURTU*, Cornel BADEA*, Alexandru STANCIU*, Adam JINARU*, Bogdan DIACONESCU*, Alin POPESCU*, Simona Badita*, Dan Argintaru**, Ion Sorin Zgura***, Catalin Ristea***, Ionut Arsene***, Daniel Felea***, Emil Stan***, Ciprian Mitu***, Mihai Potlog***, Madalin Cherciu***, Adrian Sevcenco***

Affiliation:

*University of Bucharest, Faculty of Physics

**Civilian Marine University, Sciences Chair

***Institute of Space Sciences Buchraest-Magurele

E-mail

jipa@brahms.fizica.unibuc.ro

Keywords:

Abstract:

The universal behaviour of the fragmentation processes observed up to now led to a special attention on the nuclear multifragmentation processes. In the attempt to establish the influences of the phenomena form the participant region on of the spectator regions we try to consider some possible mechanisms for the multiple nuclear fragmentation that take into account these. For this investigation we used experimental results obtained in very asymmetric proton-nucleus collisions at 8 GeV and 12 GeV, obtained at KEK Tsukuba (Japan), using as detectors Bragg counters. Some predictions on the intermediate mass fragment production are done taken into account different dynamical aspects, a few involving the competition evaporation – break-up, too. Experimental distributions obtained with Bragg Counters from KEK Tsukuba indicate some discrepancy to the scaling law. The discrepancy can be related to a random mechanism and correlative forces. A tendency to the break-up fragmentation is assumed when the atomic number of the intermediate mass fragments are greater than 15. For fragments with lower atomic numbers (Z < 5) angular distributions and energy spectra are fitted with Maxwell–Boltzmann distribution. The results suggest a statistical behaviour. The possibility to introduce for nuclear fragmentation a time scale inspired by a cosmological scenario like-Hubble using Einstein, de Sitter, Friedmann algorithms constructed for an Universe at constant entropy. Such an attempt was formerly done by our group in the case of Au + Au at . Interesting results on the production of different intermediate mass fragments are obtained. Two time scales can be considered in association with the break-up and evaporation mechanisms, respectively.