Bibcode
Nouicer, R.; Beck, C.; Sanders, S. J.; Szanto de Toledo, A.; Cavallaro, Sl.; Uegaki, E.; Abe, Y.
Referencia bibliográfica
eprint arXiv:nucl-ex/9803005
Fecha de publicación:
3
1998
Número de citas
0
Número de citas referidas
0
Descripción
Fragment-fragment-$gamma$ triple coincidence measurements of the
$^{28}$Si~$+$~$^{28}$Si reaction at E$_{
m c.m.}$~=~55.8 MeV, carefully
chosen to populate a well known quasi-molecular resonance in $^{56}$Ni,
have been performed at the VIVITRON tandem facility by using the Eurogam
Phase~II $gamma$-ray spectrometer. In the $^{28}$Si~$+$~$^{28}$Si
reaction, the resonant behavior of the $^{28}$Si $+$ $^{28}$Si
exit-channel is clearly observed by the present fragment-fragment
coincidence data. The more unexpected result is the spin disalignment of
the $^{28}$Si $+$ $^{28}$Si resonance. This has been demonstrated first
by the measured angular distributions of the elastic 0$^{+}$, inelastic
2$^{+}$ and mutual excitation channels 2$^{+}-2^{+}$, which are
dominated by a unique and pure partial wave with L = 38 ${
m hbar}$,
and has been confirmed by measuring their particle-$gamma$ angular
correlations with Eurogam Phase II. The spin disalignment supports new
molecular model predictions, in which the observed resonance would
correspond to the ''Butterfly mode''. A discussion concerning the {it
spin alignment and spin disalignment} for different systems :
$^{12}$C~$+$~$^{12}$C, $^{24}$Mg~$+$~$^{24}$Mg and
$^{28}$Si~$+$~$^{28}$Si will be given.}