Polarization transfer in 4^4He(e⃗,e′p⃗)(\vec{e},e^\prime\vec{p})3^3H: is the ratio GEp/GMpG_{Ep}/G_{Mp} modified in medium ?

Polarization observables in the $^4$He$(\vec{e},e^\prime\vec{p})$$^3$H reaction are calculated using accurate three- and four-nucleon bound-state wave functions, a realistic model for the nuclear electromagnetic current operator, and a treatment of final-state-interactions with an optical potential. In contrast to earlier studies, no significant discrepancies are found between theory and experiment both for the ratio of transverse to longitudinal polarization transfers and for the induced polarization, when free-nucleon electromagnetic form factors are used in the current operator. The present results challenge the current interpretation of the experimental data in terms of medium-modified form factors.Comment: 4 pages and 2 figue

Angular momentum dependence of the fragment kinetic energies in deeply inelastic collisions

Published in summary form onlySIGLEAvailable from CEN Saclay, Service de Documentation, 91191 Gif-sur-Yvette Cedex (France) / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

LA RÉACTION 9Be(n, nn) αα A 15 MeV

La réaction 9Be(n, nn) αα étudiée à 15 MeV, par spectrométrie à double temps de vol, a lieu par une suite de réactions à deux corps et non par un processus quasi élastique. Les niveaux du 9Be de 4 à 10 MeV et leur désintégration sont étudiés. L'influence d'une résonance à deux corps par une troisième est discutée.The 9Be(n, nn) αα reaction is analysed at 15 MeV by double time-of-flight spectrometry. The results show a sequential process of two-body reactions. The decay of the 4 to 10 MeV 9Be levels is observed and the shift of the 8Be (2 +) free resonance by a third particle is discussed