Fusion-Incomplete Fusion

1. Sez.-CT GDR pre-equilibrium emission 40Ca+48Ca,46Ti at 25 MeV/A S.Tudisco EPL 58 (5), 811(2003) M.Papa et al, PRC 68., 034606 (2003) F.Amorini et al PRC 69, 014608(2004) Fusion-Incomplete Fusion Dissipative binary processes Extra yield at 10 MeV

2. GDR pre-equilibrium emission 40Ca+48Ca,46Ti at 10 MeV/A M.Papa et al, submitted to PRC Dissipative binary processes study of kinematical coincidence

3. Z=14-22 Elab<160 MeV 40Ca+46Ti 40Ca+46Ti γ-2f 40Ca+48Ca γ-1f

4. CoMD calculations TKEL-angular and charge distrib. b-window→ pre-eq γ Yield

5. Sez.-CT How we can generate the coherent contribution? A simple picture the “Molecular Dipole” The average ensemble in an harmonic mean field The initial conditions for the GDR mode At the contact D1≈D2 ≈0 n p N1/Z1≠N2/Z2 if If Y=0 NO coherent contribution

6. Sez.-CT • Incoherent contribution • Collective • Microscopicincoherent Coherent contribution (ensemble average) Mean field approach Statistical models Fully N-body dynamical approach for 1000 fm/c

7. Sez.-CT Υ-ray average multiplicity in Semi classical Approximation The Larmor formula Fourier Transform

8. Sez.-CT b=0 fm E/A 25 MeV Langevin prediction for the total system • Prediction in the loc. Time equil. hypothesis • Prediction according to a full CoMD approach g~12 M.Papa et al, PRC 68(2003) 034606

9. Sez.-CT We have also high energy bremsstrahlung contribution We have to study the local time spectral properties of the  yield • We need to define T at long time • We need to separate the • incoherent Microscopic contribution

10. Sez.-CT High energy results Multifragmentation of the hot source

11. Sez.-CT   50 MeV/A b=0 fm M.Papa et al, PRC 68(2003) 024612  obtained from the fit procedure Very small Coherent contribution or

12. Something is changed in the fundamental properties of the formed hot sources…. Degree of collectivity-Degree of coherence as function of t

13. A new observable related to the properties of the dipolar γ-ray emission in different reaction mechanisms has been measured - Φch represents the ratio between the average and fluctuating dynamics. For N-body approaches able to evaluate the two contributions in a self consistent way, this parameter should be rather robust with respect some model ansatz: semiclassical approximaton, occupation numbers……. - On the other hand and we can expect that Φch can depend on the dynamics (Forces) governing the equilibration Process. From the experiments 10 MeV/A Binary. proc. Фch(12MeV)=0.6±0.15 Фch(10 MeV)=0.3±0.07 25 MeV/A Inc. fusion.proc.

14. c(0,tm) c(0,tf) ch(0,tf) Collectivity and Coherence for the total system limiting energy for the collective motion M.Papa et al, PRC 68(2003) 024612, Black: rather smooth behaviour 40Ca + 48Ca Central Collisions Red:it contains the Ambiguity related to the experimental selections of 1 equilibrated source *10 Green:high sensitivi ty, related to the natural time selection performed by the dynamic through memory effects.

15. CoMD calculations TKEL-angular and charge distrib. b-window→ pre-eq γ Yield

16. γ-Pre-equilibrium effects and “Isospin-Equlibration” M.Papa et al Sub. PRC Invariant with respect to secondary statistical emission processes

17. Sez.-CT Conclusive remarks • An unified description of the pre-equilibrium phenomenon (fluctuating average dynamics) has been obtained throgh ComD calculations 2. • The fluctuation predicted by the model are in agreement with Cascade calculations at 25 MeV/A by using g≈12. • 2. φch rapidly change when the multifragmentation processes set in. (much more than φc) • 3. The pre-equilibrium extra-yield it is strictly related to the • isospin equilibration process throgh a quasy-resonant mechanisms.