Angular momentum dependence of the GDR observables of A=170 nuclei at finite temperature

A recent exclusive measurement of the γ decay of the Giant Dipole Resonance in hot 176W nuclei is here presented. For the first time the two observables, strength function and angular anisotropy coefficient a2(Eγ) were measured at temperature of T=1.5 MeV at different values of the angular momentum of the compound nucleus, spanning the interval from 35 up to 55 ℎ. At this temperature shell effects are almost completely washed out and this nucleus shows deformations that are smaller than the ones at zero temperature. The a2(Eγ) and GDR width data are very well reproduced in all the selected spin windows, by predictions based on thermal shape and orientation fluctuations and using the collisional damping width at zero temperature. (author). 8 refs, 5 figs