Dynamical Dipole Mode in Fusion Heavy-Ion Reactions by ... - Infn by mamapeirong

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                    Dynamical Dipole Mode in Fusion
                    Heavy-Ion Reactions by Using Stable
                    and Radioactive Beams

             PARASCANDOLO, Concetta (Università di Padova and INFN Padova, Italy)
                        PIERROUTSAKOU, Dimitra (INFN - Napoli, Italy)
           SILVESTRI, Rosetta (Università di Napoli "Federico II" and INFN Napoli, Italy)
                          AGODI, Clementina (INFN - LNS, Catania, Italy)
                             ALBA, Rosa (INFN - LNS, Catania, Italy)
                             BOIANO, Alfonso (INFN - Napoli, Italy)
                         CONIGLIONE, Rosa (INFN - LNS, Catania, Italy)
                            DE FILIPPO, Enrico (INFN - Catania, Italy)
                         DEL ZOPPO, Antonio (INFN - LNS, Catania, Italy)
 EMANUELE, Umberto (INFN, Gruppo Collegato di Messina and Dip. di Fisica, Università di Messina,
                                              Italy)
                           FARINON, Fabio (GSI, Darmstadt , Germany)
            GUGLIELMETTI, Alessandra (Università di Milano and INFN - MIlano, Italy)
           INGLIMA, Giovanni (Università di Napoli "Federico II" and INFN Napoli, Italy)
          LA COMMARA, Marco (Università di Napoli "Federico II" and INFN Napoli, Italy)
                       MAIOLINO, Concettina (INFN - LNS, Catania, Italy)
            MARTIN, Brunella (Università di Napoli "Federico II" and INFN Napoli, Italy)
              Dr. MAZZOCCHI, Chiara (Università di Milano and INFN - MIlano, Italy)
                 MAZZOCCO, Marco (Università di Padova and INFN Padova, Italy)
                   MOLINI, Pietro (Università di Padova and INFN Padova, Italy)
                             ROMOLI, Mauro (INFN - Napoli, Italy)
            SANDOLI, Mario (Università di Napoli "Federico II" and INFN Napoli, Italy)
                      SANTONOCITO, Domenico (INFN - LNS, Catania, Italy)
                SIGNORINI, Cosimo (Università di Padova and INFN Padova, Italy)
                SORAMEL, Francesca (Università di Padova and INFN Padova, Italy)
 TRIFIRò, Antonio (INFN, Gruppo Collegato di Messina and Dip. di Fisica, Università di Messina, Italy)
  TRIMARCHI, Marina (INFN, Gruppo Collegato di Messina and Dip. di Fisica, Università di Messina,
                                              Italy)

An experimental overview [1-6] on an interesting feature of dipole excitation in heavy-ion collisions, the
dynamical dipole mode, predicted to occur between interacting ions with a large charge asymmetry will be
presented. As a fast cooling mechanism on the fusion path, the prompt dipole radiation could be of
interest for the synthesis of superheavy elements through hot fusion reactions. The entrance channel
charge asymmetry could provide a way to cool down the hot fusion paths, so ending up with a larger
survival probability.
To shed light in this direction and to study if pre-equilibrium effects survive in heavier systems than those
studied previously [3-6], we extended our study to the 192Pb compound nucleus, formed at an excitation
energy of 232 MeV, by using the 40Ca + 152Sm and 48Ca +144Sm reactions at Elab= 440 MeV and 485
MeV, respectively. These reactions populate, through entrance channels having different charge
asymmetries, the same compound nucleus formed at the same conditions of excitation energy and spin.
Preliminary results of this measurement, done with the aim to search for the dynamical dipole mode in
both fusion-evaporation and fusion-fission events for the first time in this mass region, will be presented.

The use of radioactive beams allows to attain much larger N/Z asymmetries than previously obtained
with stable beams, while the combination of exotic and stable beams results in a very large number of
target-projectile combinations that allows to perform a systematic study of the phenomenon. The
dynamical dipole prompt radiation emitted in reactions induced by radioactive beams with very large N/Z
                                                                        EURORIB’12 - Book of Abstracts



ratios can be very useful to probe the density dependence of the symmetry energy in the Equation of State
at nuclear densities lower than the saturation one, where the dynamical dipole mode is active. New
possibilities for the investigation of the symmetry energy at sub-saturation density are foreseen and will
be discussed [5].

References
[1] S. Flibotte et al., Phys. Rev. C77 (1996)1448
[2] D. Pierroutsakou et al, Eur. Phys. J. A17. (2003) 71
[3] D. Pierroutsakou et al., Phys. Rev. C71 (2005) 054605
[4] B. Martin et al., Phys. Lett. B664 (2008) 47
[5] D. Pierroutsakou et al., Phys. Rev. C 80 (2009) 024612
[6] A. Corsi et al., Phys. Lett. B 679 (2008) 197

Presenters: PARASCANDOLO, Concetta (Università di Padova and INFN Padova, Italy)

Track classification:

       Heavy and superheavy nuclei



Contribution type: oral




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