Polarization, dynamics, and nonequilibrium complex-fragment emission

Abstract

The sign of the emission angle for nonequilibrium intermediate-mass fragments was determined from the circular polarization of coincident \ensuremath{\gamma} rays for $^{14}\mathrm{induced}$ reactions on $^{154}\mathrm{Sm}$ at E/A=35 MeV. Positive polarizations, ${P}_{\ensuremath{\gamma}}$\ensuremath{\le}0.3--0.4, are observed for fragments with 3\ensuremath{\le}Z\ensuremath{\le}6, consistent with fragment emission after deflection by the attractive nuclear mean field to negative emission angles. These polarizations are small compared to the trends established for nonequilibrium light particles and the expectations of simple dynamical production mechanisms.