Peripheral fragmentation of the ${}^8$B nuclei at an energy of 1.2A GeV in nuclear track emulsion

Abstract

The results of investigations dealing with the charge topology of the fragments produced in peripheral dissociation of relativistic ${}^8$B nuclei in emulsion are presented. 55 events of peripheral dissociation of the ${}^8$B nucleus were selected from the events which do not involve the production of the target-nucleus fragments and mesons (`` white\rq\rq ~stars). A leading contribution of the ${}^8$B${\to }^7$Be+p mode having the lowest energy threshold was revealed on the basis of those events. Information on the relative probability of dissociation modes with a larger multiplicity was obtained. The dissociation of a ${}^7$Be core in ${}^8$B indicates an analogy with that of the free ${}^7$Be nucleus.\par The transverse momentum distributions of the fragments from the ${}^8$B${\to }^7$Be+p dissociation mode were obtained. Their small average value, $<$P${}_t>$= 52 MeV/c, in the c.m.s. suggests a low binding energy of the external proton in the ${}^8$B nucleus. An indication for a strong azimuthal correlation of the ${}^7$Be and p fragments was got.

13 pages, 4 figures, 2 tables, conference: Conference on Physics of Fundamental Interactions, Moscow, Russia, 5-9 Dec 2005