NUCLEAR PHYSICS



RESEARCH AREAS


PROFESSORS Ricardo A. Broglia Ettore Gadioli Ileana Iori Sergio Micheletti Marcello Pignanelli ASSOCIATE PROFESSORS Pier Francesco Bortignon Enrica Erba Elsa Fabrici Paolo Guazzoni Luisa Zetta Lina Zuffi RESEARCH ASSOCIATES Angela Bracco Franco Camera Michela Cavinato Gianluca Colò Paolo Milani Pierre Pizzochero RESEARCH FELLOWS Federico Alasia LONG TERM COLLABORATORS Eduardo Roman ADMINISTRATIVE STAFF Tiziana Bussini TECNICAL STAFF Giuseppe Di Pietro INFN STAFF RESEARCH ASSOCIATES Nives Blasi Benedicte Million Arialdo Moroni Enrico Vigezzi RESEARCH FELLOWS Armando Ferrero Silvia Leoni Erich Ormand Norberto Scoccola LONG TERM COLLABORATORS Giovanni Lo Bianco ADMINISTRATIVE STAFF Ileana Giussani TECNICAL STAFF Roberto Bassini Ciro Boiano Sergio Brambilla Angelo Cortesi GianPietro Fattori Massimo Malatesta Fabio Tomasi Ph. D. STUDENTS Marco Bianchetti Sergio Frattini Mariella Quaglia Experimental determination of nuclear properties with low-energy reations. Isospin character of low-lying states in 56Fe States up to an excitation of about 4 MeV have been investigated with (p,p') and (d,d') inelastic scattering; the deduced transition matrix elements M(E*) have been analyzed and compared with IBA-2 and shell-model calculations. The findings about the location of the quadrupole mixed- symmetry strength have been discussed. Correlations in Neodymium isotopes Excited states in 140,142,144,146Nd nuclei, up to an excitation of about 5 Mev have been studied with (p,t) reactions. The deduced B(E*) distributions have been compared with Quasi-Particle Phonon model evaluations extracting information on particle-hole and particle-particle residual interactions and on the effective interaction. Single-particle excitations in deformed nuclei The single-particle strength in 153Sm has been studied with high-resolution (d,t) and (p,d) reactions. About 170 levels were observed and several identified as members of rotational bands based on Nilsson orbitals. Strength distributions have compared with the Quasi-Particle Phonon model. (Nives Blasi, Sergio Micheletti, Marcello Pignanelli) Recent Publications: 1. R. De Leo, H. Akimune, N. Blasi, I. Daito, Y. Fujita, M. Fujiwara, S.I. Hayakawa, S. Hatori, K. Hosono, H. Ikegami, T. Inomata, I. Katayama, K. Katori, L. Lagamba, S. Micheletti, S. Morinobu, T. Nakagawa, S. Nakayama, A. Narita, T. Noro, R. Perrino, M. Pignanelli, H. Sakaguchi, J. Takamatsu, A. Tamii, K. Tamura, M. Tanaka, A. Terakawa, T. Tohei, M. Tosaki, T. Yamagata, A. Yamagoshi, M. Yosimura, M. Yosoi, "Isospin character of low-lying states in 56Fe", Phys. Rev. C53, 2718 (1996). 2. V.Yu Ponomarev, M.. Pignanelli, N. Blasi, A. Bontempi, J.A. Bordewijk, R. De Leo, G. Graw, M.N. Harakeh, D. Hofer, M.A. Hofstee, S. Micheletti, R. Perrino, S.Y. van der Werf, "Particle-hole and particle-particle correlations in neodymiun isotopes", Nucl. Phys. A601, 1 (1996). 3. N. Blasi, S. Micheletti, M. Pignanelli, et. al., "Study of 153Sm via the 154Sm(p,d) reaction", submitted to Nucl. Phys. (1996). Few Nucleon Transfer Reactions. The aim of the research developed and to be carried on is the study of nuclear structure and reaction mechanism by means of spectroscopic techniques in processes induced by polarized and not polarized particles and involving few nucleon transfer. We have studied (p,*) and (p,t) reactions on magic and quasi-magic nuclei with an unpaired nucleon outside the magic shell. By means of the concept of homology we have identified spin, parity and dominant configuration of many levels at relatively high excitation energy and we have performed a direct comparison with the shell model expectations. To this research line collaborate national (Department of Physics Padova, prof. Vitturi, Department of Physics Napoli, prof. Covello) and international institutions (Ludwig Maximilian Universität, Munchen, prof. Graw; Physikalisches Institut, Tübingen, prof. Staudt; Soltan Institute for Nuclear Studies, Warsaw, prof. Jaskola). (Luisa Zetta) Recent Publications: 1. U. Atzrott, Gh. Cata-Danil, G. Graw, P. Guazzoni, J.N.Gu, R. Hertenberger, D. Hofer, M. Jaskola, G. Staudt, B. Valnion, A. Vitturi, E. Zanotti-Müller, L. Zetta, "Nuclear Spectroscopy of 88Y", "Proceedings of the XV Nuclear Physics Divisional Conference LEND95" St. Petersburg (Russia) April 18-22, (1995) - World Scientific, pag. 625 (1995). 2. P. Guazzoni, U. Atzrott, G. Cata-Danil, G. Graw, J.N. Gu, R. Hertenberger, M. Jaskola, P. Schiemenz, G. Staudt, A. Vitturi, L. Zetta, "(p,*) reactions on odd-mass target nuclei", Report INFN/BE - 95/04 (1995). 3. G. Cata-Danil, A. Gollwitzer, G. Graw, P. Guazzoni, J.N. Gu, R. Hertenberger, M. Jaskola, G. Staudt, B. Valnion, A. Vitturi, L. Zetta, "Study of the 45Sc (p,*) 42Ca reaction", Jahresberict 1995, Universität Munchen (1996). 4. G. Graw, P. Guazzoni, J.N. Gu, R. Hertenberger, M. Jaskola, G. Staudt, A. Vitturi, L. Zetta, "Shell model calculations in the lead region", Jahresbrict 1995, Universität Munchen (1996). 5. G. Cata-Danil, G. Graw, P. Guazzoni, J.N. Gu, R. Hertenberger, M. Jaskola, G. Staudt, A. Vitturi, L. Zetta, "Shell model calculations for 88Y", Jahresbrict 1995, Universität Munchen (1996). 6. G. Cata-Danil, P. Guazzoni, M. Jaskola, L. Zetta, G. Graw, R. Hertenberger, D. Hofer, P. Schiemenz, B. Valnion, E. Zanotti-Müller, U. Atzrott, F. Hoyler, F. Nuoffer, G. Staudt, "(p,t) transitions strengths for nuclei around Z=50 and the IBA model", J. Phys. G. Nucl. Part. Phys., 22 (1996) 107. 7. P. Guazzoni, L. Zetta, P. Demetriou, P.E. Hodgson, "Multistep direct analysis of (p,*) reactions to the continuum", Zeit. Phys. A354 (1996) 53 and OUNP-96-03 Report (1996). 8. P. Guazzoni, L. Zetta, J.N. Gu, A. Vitturi, G. Graw, R. Hertenberger, P. Schiemenz, M. Jaskola, U. Atzrott, G. Staudt, "Spectroscopy of 87Y via 90Zr (p,*) 87Y reaction", EPS10- Trends in Physics, Sevilla September 9-13 (1996). On-line Computational System. The argument of this research is the identification of charged reaction products, using the power- law for a fast on-line computing of the Particle Identification Function, PIF=(E+DE)x-Ex. The first approach we are following is the development of a system based on commercial Digital Signal Processor (DSP) who allows a very fast computation of PIF (~ 10 *s). The computation of PIF is done as floating point sum and product iterations, by means of elementary operators, using the expansion in series of Chebycheff polynomials and the Hörner ordering method. In this way is possible to reduce the number of iterations. Moreover the DSP allows to operate with a reduced- mantissa word (11-bit instead of 23-bit), further reducing the computation time. (Paolo Guazzoni) Recent Publications: 1. A. Pagano, S. Aiello, P. Guazzoni, L. Zetta, et. al., "A new multielement detector system at LNS for heavy ion reaction studies at intermediate energies", "Proceedings of the 2nd Japan- Italy Joint Symposium '95" Riken May 22-26, 1995- World Scientific, 119 (1995). 2. S. Aiello, P. Guazzoni, L. Zetta, et. al., "Chimera: a project of 4* detector for heavy ion reaction studies at intermediate energy", Nucl. Phys. A583, 461 (1995). 3. S. Aiello, M. Bartolucci, P. Guazzoni, G. Manfredi, L. Zetta, et. al., "Real Time Computing of Special Algorithms with DSP - based board", "Proceedings of the 8th Euromicro Workshop on Real Time Systems", L'Aquila June 12-14, pag. 57 (1996). 4. S. Aiello, P. Guazzoni, L. Zetta, et. al., "Light response and particle identification with large CsI(Tl) crystals coupled to photodiodes", Nucl. Instr. Methods A369, 50 (1996). The SPREAD experiment and the SUPERNOVA collaboration. SUPERNOVA is an european collaboration between several Physics Departments of the Universities: Bari, Darmstadt, Gent, Groningen, Madrid, Milano and Münster. The primary goal of this collaboration is to measure the low-multipolarity (L=0, 1, 2) spin-flip and non spin-flip cross sections for sd- and fp-shell nuclei. Apart from addressing the still open question of quenching, such experimental information is also a key ingredient for a quantitative modeling of neutrino nucleosynthesis in type II Supernovae explosions. Inelastic scattering off nuclei ti the continuum with subsequent particle emission contributes significantly to the nucleosynthesis of many elements. A proton polarimenter device for medium energy protons has been designed, built and instrumented around the Big-Bite magnetic Spectrometer (BBS) of the AGOR facility at the KVI Groningen. The device will be utilized for an experimental program aimed at exploring the explosion dynamics of a supernova and the various particle physics processes that cause its ignition. The construction of the proposed device and its instrumentation with the appropriate electronic hardware constitutes an engeneering challenge in many ways. The group from Milano is giving contributions to the front end electronics. An extreme data rates handling capability (108 events/s) is achieved through many incorporated features in cards specially designed. (Roberto Bassini, Nives Blasi, Sergio Brambilla, Massimo Malatesta, Sergio Micheletti, Marcello Pignanelli) Recent Publications: 1. M.A. Hofstee, S.Y. van der Werf, A.M. van der Berg, N. Blasi, J.A. Bordwijk, W.T.A. Borghols, R. De Leo, G.T. Emery, S. Fortier, S. Galés, M.N. Harakeh, P. den Heijr, C.W. de Jager, H. Langevin-Joliot, S. Micheletti, M. Morlet, M. Pignanelli, J.M. Schippers, H. de Vries, A. Willis, A. van der Woude, "Localized 1 h* particle-hole strength in nuclei", Nucl. Phys. A588, 729 (1995). The EUROBALL Project. EUROBALL (EB) is an European collaboration to build a highly efficient *-ray spectrometer for nuclear spectroscopy. The EB collaboration is active since 1988-89 and involves physicists coming from 28 laboratories of 6 different countries: United Kingdom, . Million, M. Pignanelli, J.J.Gaardøje, Z. Zelazny, T. Ramsøy, T. Tveter, A. Maj, "The GDR at finite temperature in medium and very heavy mass regions", Nuclear Physics A583, 83c (1995). 2. A. Bracco, F. Camera, M. Mattiuzzi, B. Million, M. Pignanelli, J.J.Gaardøje, Z. Zelazny, T. Ramsøy, T. Tveter, A. Maj, "Increase of the width of the Giant Dipole Resonance in hot Nuclei: Shape Change or Collisional Damping?", Phys. Rev. Lett. 74, 3784 (1995). 3. M. Mattiuzzi, A. Bracco, F. Camera, B. Million, M. Pignanelli, J.J.Gaardøje, A. Maj, T. Ramsøy, T. Tveter, Z. Zelazny, "Thermal Fluctuation and collisional damping effects in the GDR observables in hot rotating 176W nuclei", Phys. Lett. B364, 13 (1995). 4. T.S. Tveter, J.J.Gaardøje, A. Maj, T. Ramsøy, A. Atac, J. Bacelar, A. Bracco, A. Buda, F. Camera, B. Herskind, W. Korten, W. Krolas, A. Menthe, B. Million, H. Nifenecker, M. Pignanelli, J.A. Pinston, H.v.d. Ploeg, F. Schussler, G. Sletten, "Collective Dipole Motion in Highly Excited 272Hs(Z=108) Nuclei", Phys. Rev. Lett. 76, 1035 (1996). 5. A. Bracco, F. Camera, M. Mattiuzzi, B. Million, M. Pignanelli, J.J.Gaardøje, A. Maj, Z. Zelazny, "The damping of the GDR at finite temperature: recent progress", Proceeding of the XXIX Zakopane School of Physics, September 1994, Acta Polonica, Vol. B 26, 407 (1995). 6. M. Mattiuzzi, A. Bracco, F. Camera, J.J.Gaardøje, A. Maj, Z. Zelazny, "Spin Dependencew of the GDR observable of hot rotating A=170 Nuclei", Proceeding of the XXIX Zakopane School of Physics, september 1994. Acta Polonica, Vol. B 26, 467 (1995). 7. F. Camera, M. Mattiuzzi, A. Bracco, J.J.Gaardøje, A. Maj, G. Lo Bianco, I.G. Bearden, P. Bosetti, Z. Zelazny, "Detecting High Energy Gamma rays with HpGe Detectors", Proceeding of the XXIX Zakopane School of Physics, september 1994. Acta Polonica, Vol. B 26, 479 (1995). 8. A. Maj, T. Tveter, J.J.Gaardøje, B. Herskind, G. Sletten, T. Ramsøy, A. Atac, W. Korten, A. Bracco, F. Camera, B. Million, M. Pignanelli, J. Bacelar, A. Buda, -Quantum Number in Excited Rotating Nuclei", Phys. Lett. 76, 1204 (1996). 3. A. Bracco, P. Bosetti, S. Frattini, E. Vigezzi, S. Leoni, B. Herskind, T. Døssing, M. Matsuo, "Microscopic simulation *-cascades in warm rotating nuclei", Phys. Rev. Lett. 76, 4484 (1996). 4. A. Nordlund, R. Bengtsson, P. Ekström, M. Bergström, A. Brockstedt, H. Carlsson, H. Ryde, Y. Sun, A. Ataç, G.B. Hagemann, B. Herskind, J.J. Jongman, S. Leoni, A. Maj, J. Nyberg, P.O. Tjøm, "Probing the limits of complete spectroscopy in 164Yb", Nucl. Phys. A591, 117 (1995). 5. R.A. Bark, G.B. Hagemann, B. Herskind, H.J. Jensen, W. Korten, J. Wrzesinski, H. Carlsson, M. Bergstrom, A. Brockstedt, A. Nordlund, H. Ryde, P. Bosetti, S. Leoni, F. Ingebretsen, P.O. Tjøm, "More than third bands in 177Re", Nucl. Phys. A591, 265 (1995). 6. H. Schnack-Petersen, R. Bengtsson, R.A. Bark, P. Bosetti, A. Brockstedt, H. Carlsson, L.P. Ekström, G.B. Hagemann, B. Herskind, F. Ingebretsen, H.J. Jensen, S. Leoni, A. Nordlund, H. Ryde, P.O. Tjøm, C.X. Yang, "Superdeformed triaxal bands 163,165Lu", Nucl. Phys. A594, 175 (1995). 7. R.A. Bark, S.W. Ødegård, R. Bengtsson, I.G. Bearden, G.B. Hagemann, B. Herskind, F. Ingebretsen, S. Leoni, H. Ryde, T. Shizuma, K. Strähle, P.O. Tjøm, J. Wrzesinski, "Intruder Bands Extended in 175Re and 177Ir: Deforming changes and Interaction at the Alignment of i13/2 Neutrons", Phys. Rev. C52, R450 (1995). 8. S. Leoni, B. Herskind, T. Døssing, K. Yoshida, M. Matsuo, A. Ataç, G.B. Hagemann, F. Ingebretsen, H.J. Jensen, R.M. Lieder, G.V. Marti, N. Nica, J. Nyberg, M. Piiparinen, H. Schnare, G. Sletten, K. Strähle, M. Sugawara, P.O. Tjøm, A. Virtanen, "A Finite Number of Regular Rotational Bands in the Superdeformed Well of 143Eu", Phys. Lett. B353, 179 (1995). 9. B. Herskind, S. Leoni, T. Døssing, G.B. Hagemann, P. Bosetti, A. Bracco, S. Frattini, E. Vigezzi, M. Matsuo, "Towards Complete Spectroscopy in Rapidly Rotating Nuclei", Acta Phys. Pol. B, Vol. 26, p. 153 (1995). 10. S. Leoni, B. Herskind, T. Døssing, A. Ataç, "Observation of an Intense Quasi-Continuum of Superdeform Transition in 143Eu", Phys. Rev. Lett. 76, 3281 (1996). Nuclear spectroscopy using the GASP spectrometer. Nuclear strucutre studies have been performed by means of in-beam *-rays spettroscopy using the GASP array in two mass regions. In the 121,123Te isotopes we searched for high spin rotational bands based on the intruder 4-particle 2-hole configuration, which was recently found in the doubly-even 122Te. In the odd-odd 162,164Lu isotopes, we studied the strucutre of the yrast band based on the *h11/2 *i13/2 configuration, which shows the signature inversion feature. (Giovanni Lo Bianco, Nives Blasi) Recent Publications: 1. N. Blasi, G. Falconi, G. Lo Bianco, Ch. Protochristov, D. Bazzacco, G. De Angelis, D.R. Napoli, "High-spin states in 121Te", Z. Phys. A352, 359 (1995). 2. U.J. van Severen, W. Korten, H. Hubel, D. Bazzacco, G. Lo Bianco, N.H. Medina, C. Rossi-Alvarez, S. Signorelli, K. Strahle, P. Willsau, "A pair of superdeformed bands in 196Pb", Z. Phys. A353, 15 (1995). 3. M.A. Cardona, M.E. Debray, D. Hojman, A.J. Kreiner, H. Somacal, J. Davidson, M. Davidson, D. De Acuna, D.R. Napoli, J. Rico, D. Bazzacco, R. Burch, S.M. Lenzi, C. Rossi-Alvarez, N. Blasi, G. Lo Bianco, "Yrast bands and signature inversion in doubly odd 162,164Lu", Z. Phys. A354, 5 (19956). 4. N. Blasi, G. Lo Bianco, Ch. Protochristov, D. Bazzacco, G. Falconi, N.H. Medina, G. De Angelis, D.R. Napoli, "High-spin states in 123Te", Z. Phys. A354, 233 (1996). 5. G. Baldsiefen, H. Hubel, W. Korten, U.J. van Severen, J.A. Cizewski, D. Bazzacco, N.H. Medina, C. Rossi-Alvarez, G. Lo Bianco, S. Signorelli," Crossing of Shear Bands in 196Pb", Z. Phys. A355, 337 (1996). Comprehensive study of the interaction of 12C with medium mass nuclei up to 35 MeV/Amu. Fifty-three excitation functions for the production of radioactive residues in the interaction of 12C with 103Rh have been measured from the Coulomb barrier up to 400 MeV by means of the activation technique. These excitation functions have been analyzed with very satisfactory results considering complete fusion, incomplete fusion of 8Be and *-particle fragments and, above about 200 MeV, the transfer of either one proton or one neutron from 12C to 103Rh. The emission of pre-equilibrium particles during the thermalization of the excited composite nuclei formed in all these processes and, in the case of 8Be and * incomplete fusion, also the re-emission of *- particles after a mean-field interaction or a few interactions with the target nucleon have been taken into account. To our knowledge, comprehensive calculations of comparable accuracy, in energy ranges as wide as ours, have not been reported in the literature previously. We are of the opinion that our results may be applicable more generally to the study of the interaction of 12C with nuclei, since they are not sensitive to the strucutre of 103Rh. (Claudio Birattari, Michela Cavinato, Elsa Fabrici, Ettore Gadioli, Enrica Gadioli Erba) Recent Publications: 1. C. Birattari, M. Bonardi, C. Bovati, C. Brusati, M. Cavinato, A. Di Filippo, E. Fabrici, E. Gadioli, E. Gadioli Erba, T. Stevens, S.H. Connell, J.P.F. Sellschop, S.L. Mills, G.P. Steyn, F.M. Nortier, "Comprehensive study of the reactions induced by 12C ions on 103Rh up to 230 MeV", Contribution to the International Nuclear Physics Conference, Bejing, August 21-26 (1995). 2. E. Gadioli, P. Vergani, M. Cavinato, E. Fabrici, E. Gadioli, E. Gadioli Erba, M. Crippa, G. Colombo, I. Redaelli, M. Ripamonti. C. Brusati, G. Ciavola, C. Marchetta, S.H. Connell, "Pre-equilibrium emission and incomplete fusion in heavy ion reactions at energies around the Coulomb barrier", in Proceedings of the Tours Symposium on Nuclear Physics II, World Scientific, pgg. 309-38 (1995). 3. M. Cavinato, E. Fabrici, E. Gadioli, E. Gadioli Erba, P. Vergani, M. Crippa, G. Colombo, I. Redaelli, M. Ripamonti, "Study of the reactions occurring in the fusion of 12C and 16O with heavy nuclei at incident energies below 10 MeV/nucleon", Phys. Rev. C52, 2577 (1995). 4. C. Birattari, M. Bonardi, E. Gadioli, M. Cavinato, E. Fabrici, E. Gadioli Erba, M. Bello, C. Bovati, A. Di Filippo, F. Groppi, T. Stevens, S.H. Connell, J.P.F. Sellschop, S.J. Mills, G.P. Steyn, F.M. Nortier, "Study of the interaction of 12C with 103Rh", NAC Annual Report (1995). 5. C. Birattari, M. Bonardi, E. Gadioli, I. Redaelli, M. Ripamonti, P. Vergani, G. Ciavola, C. Marchetta, "Angular distribution of heavy residues in the interaction of 16O with 181Ta below 8.5 MeV/Amu", Annual Report del Laboratorio Nazionale del Sud (1995). 6. C. Birattari, M. Bonardi, E. Gadioli, I. Redaelli, M. Ripamonti, M. Cavinato, E. Fabrici, E. Gadioli Erba, "Study of the interaction of 12C with 103Rh up to 8.2 MeV/Amu", Annual Report del Laboratorio Nazionale del Sud (1995). 7. E. Gadioli, "Nuclear activation studies of heavy ion reactions", Heavy Ion Physics 2, 161 (1995). 8. C. Birattari, M. Bonardi, M. Cavinato, E. Fabrici, E. Gadioli, E. Gadioli Erba, F. Groppi, M. Bello, C. Bovati, A. Di Filippo, T. Stevens, S.H. Connell, J.P.F. Sellschop, S.J. Mills, F.M. Nortier, G.P. Steyn, "Nuclear activation study of 12C + 103Rh interaction from 150 MeV to 400 MeV incident energy", NAC Annual Report (1996). 9. C. Birattari, M. Bonardi, M. Cavinato, E. Fabrici, E. Gadioli, E. Gadioli Erba, F. Groppi, M. Bello, C. Bovati, A. Di Filippo, T. Stevens, S.H. Connell, J.P.F. Sellschop, S.J. Mills, F.M. Nortier, G.P. Steyn, C. Marchetta, "Pre-equilibrium processes in the fusion of 12C with 103Rh up to 20 Mev/nucleon", Phys. Rev. C54, 3051 (1996). 10. E. Gadioli, C. Birattari, M. Cavinato, E. Fabrici, E. Gadioli Erba, V. Allori, C. bovati, F. Cerutti, A. Di Filippo, E. Galbiati, T. Stevens, S.H. Connell, J.P.F. Sellschop, S.J. Mills, F.M. Nortier, G.P. Steyn, C. Marchetta, "Comprehensive study of the interaction of 12C with 103Rh up to 33 MeV/nucleon", Invited talk to the International Symposium on Large Scale collective motion of Atomic Nuclei, Brolo (1996), in corso di pubblicazione su World Scientific, Publ. Co. Ltd, Singapore (1996). The Boltzmann Master Equation Theory of nuclear reactions. Three important improvements have been made to the Boltzmann Master Equation theory of nuclear reactions that we have extensively used to predict the processes occurring during the thermalization of the excited nucleus formed in the interaction of two heavy ions: a) mean field effects and the shell structure of the interacting ions have been explicitly included in the calculation, b) the multiplicities of particles emitted during small time intervals, predicted by the theory, have been used in a Monte Carlo calculation to predict possible sequences of events and hence the cross-sections and other measurable observables of individual reactions. This greatly extends the range of applicability of the theory that so far has been used to predict angle integrated average particle multiplicities, c) the theory has been extended to predict the ejectile angular distributions with very satisfactory results. The new possibility of estimating how the nucleon momentum correlation disappears with increasing time, allows one to predict more accurately than with previous calculations the absolute value of the cross-sections for complex particle emission. (Michela Cavinato, Elsa Fabrici, Ettore Gadioli, Enrica Gadioli Erba) Recent Publications: 1. C. Brusati, M. Cavinato, E. Fabrici, E. Gadioli, E. Gadioli Erba, "Nuclear Surface, mean field and isospin effects in Boltzmann master equation theory of pre-equilibrium reactions", Z. Phys. A353, 57 (1995). 2. M. Cavinato, E. Fabrici, E. Gadioli, E. Gadioli Erba, "Nuclear thermalization", Heavy ion Physics 2, 225 (1995). 3. M. Cavinato, E. Fabrici, E. Gadioli, E. Gadioli Erba, E. Galbiati, "Monte Carlo calculations using the Boltzmann master equation theory of nuclear reactions", Phys. Letter. B382, 1 (1996). Nucleus-nucleus collisions at intermediate and relativistic energies. Experimental field of research devoted to the study of nuclear reactions induced by heavy ions in the energy range 20 A MeV-1 A GeV. The experiments at beam energy lower than 100 A MeV are performed at cyclotron accelerators. For the detection and identification of Intermediate Mass Fragments (IMF) an array of telescope detectors has been built, with low threshold in a wide charge range, good granularity and good geometrical efficiency in the covered angular region. It has a large dynamical range and it identifies the IMF charge till to the beam charge (it has been used with Au beam). For the lighter ions, to C and N, a good isotope separation has been achieved. Each telescope is made of an axial ionization chamber filled with CF4 a Si detector position sensitive in two ortogonal directions, a SiLi thick detector and Csl(Tl) scintillator read by a photodiode. Several experiments have been performed: at the GANIL (Grand Accelerateur National de Ion Lourdes) in Caen (France) with Xe beam at 35 A MeV and at the Superconducting Cyclotron of the M.S.U. (Michigan State University, USA), with Xe and Au beams up to 70 A MeV energy. In these experiments our array has been coupled to the M.S.U. MINIBALL detector a high efficiency scintillation array for light ions (to Z=20). In such a way a detection system with very good coverage and low threshold has been obtained. Different processes have been studied: for central collisions a break up of a unique source has been found. For Xe + Cu at 30 A MeV, from the correlatin functions, the space-time characteristics of the fragment emission have been deduced. The telescope array, at the moment consisting of about 70 elements, recently has been installed at the Superconducting Cyclotron of the L.N.S. in Catania: there it has been coupled to the detector MEDEA a scintillator ball with good efficiency for gamma and light particles. Experiments are in progress with a Ni beam at 30 and 45 A MeV. These experiments are devoted to the investigation of the dynamics in the nuclear multifragmentation process and to the study of the decay of hot nuclear systems. From the light fragments isotope ratios, the nuclear temperature has been deduced. The Multifragmentation process at energies from 100 AMeV to 1 A GeV, is investigated at the synchroton SIS of the G.S.I. (Darmstadt - Germany), in an international collaboration (ALADIN). The multi fragment decay of heavy projectiles is explored in a wide range of projectiles and targets and at relativistic energie, between 400 an 1000 A MeV. For these experiment the ALADIN spectrometer is used, with a tracking detector TP-MUSIC and a T.O.F. wall behind it. A Si-CSi hodoscope with good coverage is located at forward angles. This hodoscope and its electronics have been built and are responsability of the italian part of the collaboration (Mi-Ct). In pheripheral collision at energies higher than 400 A MeV, the systematics shows a universal behaviour for the fragmentation of excited projectile spectators. For the reaction Au + Au at 600 A MeV, a temperature scale has been constructed from the isotope ratios of He and Li and the excitation energy of the pre-fragments has been evaluated. The relation between the isotopic temperature and the excitation energy per nucleon, shows an interesting behaviour: the temperature is almost constant at about 5 Mev, in a range of excitation energy between 3 and 8 MeV/nucleon, as if a phase transition of nuclear matter were present. This kind of experiment devoted to the temperature measurement, will be performed at lower energy at the Tandem accelerator and at the Superconducting Cyclotron of the L.N.S. where the hodoscope will be installed. HADES. HADES is a High Acceptance DiElectron Spectrometer which will be devoted to the study of nuclear properties in dense hadronic matter. The scope of the research is the spectroscopy of lepton pairs in Heavy Ion Collisions: In Au + Au collisions at beam energy 1 A GeV, it is evaluated that, in the interaction zone, the density reaches three times the normal density of hadronic matter. A consistent activity in heavy ion nuclear physics, is devoted to the investigation of the nuclear matter Equation Of State (EOS); no direct informations are possible but some are deduced by comparison with model calculations. The results, however, suffer of some ambiguity, as the knowledge of fundamental quantity in dense nuclear matter are needed. They are the nucleon-nucleon cross section, the cross section for particle production etc. that could be modified in dense nuclear matter. Some fundamental hadron properties, as masses, decay constants, form factors etc. in the framework of QCD calculations, could be modified in dense nuclear matter. HADES is a lepton spectrometer that can detect processes at small cross section in a high background sorraundings. The experiments will be performed at the GSI with heavy ion beams and with a K beam that will be installed in the future. With different kinds of beams, different density and temperature conditions will be reached. HADES is a multiplicity of detectors; a RICH (gas Cherenkov), large drift chambers, a toroidal superconducting magnet, a shower detector and a TOF wall. The italian partecipant (mi-Ct) is responsible of the construction of the large TOF wall made of about 1000 rods of plastic scintillators anf of the read out fast electronics. (Ileana Iori, Arialdo Moroni, Francesco Petruzzelli, Wei Zhiyong, Roberto Bassini, Sergio Brambilla, Cosimo Carriero, Ciro Boiano) Recent Publications: 1. A.S. Botvina, A.N. Mishustin, M. Begemann-Blaich, J. Hubele, G. Immè, I. Iori, P. Kreutz, G.J. Kunde, W.D. Kunze, V. Lindestruth, U. Lynen, A. Moroni, W.F.J. Müller, C.A. Ogilvie, J. Pochodzalla, G. Raciti, Th. Rubehn, H. Sann, A. Schüttauf, W. Seidel, W. Trautmann, A. Wörner, "Multifragmentation of spectator in relativistic heavy ion reactions", GSI 94-36, Juni 1994. Nucl. Phys. A584, 737 (1995). 2. A. Moroni, D.R. Bowman, M. Bruno, P. Buttazzo, L. Celano, N. Colonna, M. D'Agostino, J.D. Dinius, A. Ferrero, M.L. Fiandri, K. Gelbke, T. Glasmacher, F. Gramegna, D.O. Handzy, D. Horn, Wen-Chien Hsi, M. Huang, I. Iori, M. Lisa, W.G. Lynch, G.V. Margagliotti, P.F. Mastinu, P.M. Milazzo, C. Montoya, G.F. Peaslee, L. Phair, F. Petruzzelli, R. Rui, R. Scardaoni, C. Schwarz, B. Tsang, G. Vannini, C. Williams, "Multifragment Emission Times in Xe Induced reactions", Nucl. Phys. A583, 531 (1995). 3. J. Pochodzalla, S. Aiello, M. Begemann-Blaich, Th. Blaich, D.R. Bowman, R.J. Charity, A. Cosmo, A. Ferrero, C.K. Gelbke, W.C. Hsi, J. Hubele, G. Immè, I. Iori, J. Kempter, P. Kreutz, G.J. Kunde, W.D. Kunze, V. Lindenstruth, M.A. Lisa, W.G. Lynch, U. Lynen, M. Mang, L.G. Moretto, A. Moroni, W.F.J. Müller, M. Neumann, B. Ocker, C.A. Ogilvie, V. Pappalardo, G.F. Peaslee, G. Raciti, F. Rosenberger, T. Rubenhn, H. Sann, A. Schüttauf, W. Seidel, V. Serfling, L.G. Sobotka, J. Stroth, L. Stuttge, W. Trautmann, M.B. Tsang, A. Tucholski, C.W. Williams, A. Worner, E. Zude, B. Zwieglinski, "Multifragmentation and Flow: peripheral versus central collisions", Nucl. Phys. A583, 553 (1995). 4. G.J. Kunde, W.C. Hsi, W.D. Kunze, A. Schüttauf, A. Worner, S. Aiello, M. Begemann- Blaich, Th. Blaich, D.R. Bowman, R.J. Charity, A. Cosmo, A. Ferrero, C.K. Gelbke, J. Hubele, G. Immè, I. Iori, J. Kempter, P. Kreutz, V. Lindestruth, M.A. Lisa, W.G. Lynch, U. Lynen, M. Mang, A. Moroni, L. Moretto, W.F.J. Müller, M. Neumann, B. Ocker, C.A. Ogilvie, V. Pappalardo, G.F. Peaslee, J. Pochodzalla, G. Raciti, F. Rosenberger, T. Rubenhn, H. Sann, W. Seidel, V. Serfling, L.G. Sobotka, J. Stroth, L. Stuttge, W. Trautmann, M.B. Tsang, A. Tucholski, C.W. Williams, A. Worner, E. Zude, B. Zwieglinski, "Fragment flow and multifragmentation phase space", Phys. Rev. Lett. 74, 38 (1995). 5. M. D'Agostino, M. Bruno, F. Gramegna, I. Iori, P.F. Mastinu, P. Milazzo, E. Plasgnol, G. Vannini, "Time scale and freeze-out volume in Xe + Cu reaction at 45 MeV/u", Zeit. für Physics A373, 191 (1995). 6. J. Pochodzalla, T. Möhlenkamp, T. Rubehn, A. Schüttauf, A. Worner, E. Zude, M. Begemann-Blaich, Th. Blaich, C. Gross, H. Emling, A. Ferrero, G. Immè, I. Iori, G.J. Kunde, W.D. Kunze, V. Lindestruth, U. Lynen, A. Moroni, W.F.J. Müller, B. Ocker, G. Raciti, H. Sann, C. Schwarz, W. Seidel, V. Serfling, J. Stroth, A. Trzcinski, W. Trautmann, A. Tucholski, G. Verde, B. Zwieglinski, "Probing, the liquid, gas phase transition", GSI 95- 13, February 95, Phys. Rev. Lett., 1040 (1995). 7. W. Trautmann, M. Begemann-Blaich, Th. Blaich, H. Emling, A. Ferrero, C. Gross, G. Immè, I. Iori, G.J. Kunde, W.D. Kunze, V. Lindestruth, U. Lynen, T. Möhlenkamp, A. Moroni, W.F.J. Müller, B. Ocker, J. Pochodzalla, G. Raciti, T. Rubehn, H. Sann, A. Schüttauf, C. Schwarz, W. Seidel, V. Serfling, J. Stroth, A. Trzcinski, A. Tucholski, G. Verde, A. Worner, E. Zude, B. Zwieglinski, "Formation and decay of equilibrated spectator nuclei at relativistic bombarding energies", XXXIII Int. Meeting on Nucl. Phys. - Bormio 95 - Ric. Sc. & Ed. Perm. Suppl. N. 101 pag. 372 (1995). 8. T. Möhlenkamp, M. Begemann-Blaich, Th. Blaich, H. Emling, A. Ferrero, C. Gross, G. Immè, I. Iori, G.J. Kunde, W.D. Kunze, V. Lindestruth, U. Lynen, A. Moroni, W.F.J. Müller, B. Ocker, J. Pochodzalla, G. Raciti, T. Rubehn, H. Sann, A. Schüttauf, C. Schwarz, W. Seidel, V. Serfling, J. Stroth, W. Trautmann, A. Trzcinski, A. Tucholski, G. Verde, A. Worner, E. Zude, B. Zwieglinski, "Isotope ratios of light fragments as thermometers in heavy ion collisions", XXXIII Int. Meeting on Nucl. Phys. - Bormio 95 - Ric. Sc. & Ed. Perm. Suppl. N. 101 pag. 383 (1995). 9. W.F.J. Müller, M. Begemann-Blaich, Th. Blaich, C. Gross, H. Emling, A. Ferrero, G. Immè, I. Iori, G.J. Kunde, W.D. Kunze, V. Lindestruth, U. Lynen, T. Möhlenkamp, A. Moroni, B. Ocker, J. Pochodzalla, G. Raciti, T. Rubehn, H. Sann, A. Schüttauf, C. Schwarz, W. Seidel, V. Serfling, J. Stroth, W. Trautmann, A. Trzcinski, A. Tucholski, G. Verde, A. Worner, E. Zude, B. Zwieglinski, "Phase transitions in nuclear systems" XXXIII Int. Meeting on Nucl. Phys. - Bormio 95 - Ric. Sc. & Ed. Perm. Suppl. N. 1021 pag. 394 (1995). 10. Th. Rubehn, W.F.J. Müller, R. Bassini, M. Begemann-Blaich, Th. Blaich, A. Ferrero,C. Gross, G. Immè, I. Iori, G.J. Kunde, W.D. Kunze, V. Lindestruth, U. Lynen, T. Möhlenkamp, L.G. Moretto, G. Ocker, J. Pochodzalla, G. Raciti, S. Reito, H. Sann, A. Schüttauf, W. Seidel, V. Serfling, W. Trautmann, A. Trzcinski, G. Verde, A. Worner, E. Zude, B. Zwieglinski, "electromagnetic fission of 238U at 600 and 1000 MeV per nucleon", GSI-95-28 Mai 95 Zeitschrift für physik A353, 197 (1995). 11. D.R. Bowman, N. Colonna, W.A. Friedman, L. Celano, M. D'Agostino, J.D. Dinius, A. Ferrero, C.K. Gelbke, T. Glasmacher, D.O. Handzy, D. Horn, W.C. Hsi, M. Huang, I. Iori, M. Lisa, W. Lynch, G. Matgagliotti, P. Milazzo, C. Montoya, A. Moroni, G. Peaslee, F. Petruzzelli, L. Phair, R. Scardaoni, C. Schwarz, M.B. Tsang, C. Williams, "Space time characterisitcs of fragment emission in the E/A 30 MeV 129Xe + natCu reaction", TASCC- P-95-3 Febb. 95 Phys. Rev. C52, 818 (1995). 12. M.B. Tsang, P. Danielewicz, W.C. Hsi, M. Huang, W. Lynch, D. Bowman, C.K. Glebke, M. Lisa, G.F. Peaslee, R.J. Charity, L.G. Sobotka, M. Begemann-Blaich, F. Cosmo, A. Ferrero, J. Hubele, G. Immè, I. Iori, J. Kempter, P. Kreutz, G.J. Kunde, W.D. Kunze, V. Lindestruth, U. Lynen, M. Mang, A. Moroni, W.F.J. Müller, M. Neumann, B. Ocker, C.A. Ogilvie, J. Pochodzalla, G. Raciti,F. Rosemberg, T. Rubehn, H. Sann, R. Scardaoni, A. Schüttauf, C. Schwarz, W. Seidel, V. Serfling, W. Trautmann, A. Tucholski, A. Wörner, B. Zwieglinski, "The Aladin Collaboration Squeze out of nuclear matter in Au + Au collisions", MSUCL- 983 November (1995). 13. Th. Rubehn, R. Bassini, M. Begemann-Blaich, Th. Blaich, A. Ferrero, C. Gross, G. Immè, I. Iori, G.J. Kunde, W.D. Kunze, V. Lindestruth, U. Lynen, T. Möhlenkamp, L.G. Moretto, W.F.J. Müller, G. Ocker, J. Pochodzalla, G. Raciti, S. Reito, H. Sann, A. Schüttauf, W. Seidel, V. Serfling, W. Trautmann, A. Trzcinski, G. Verde, A. Wörner, B. Zwieglinski, "Charge pick-up of 238U at relativistic energies", GSI-95-60 October 95 Phys. Rev. C53, 993 (1995). 14. A. Ferrero, I. Iori, A. Moroni, F. Petruzzelli, R. Scardaoni, G. Moretto, D.R. Bowman, M. Bruno, P. Buttazzo, L. Celano, N. Colonna, M. D'Agostino, J.D. Dinius, L. Fiandri, E. Fuschini, C.K. Gelbke, T. Glasmacher, F. Gramegna, D.O. Handzy, D. Horn, W.C. Hsi, M. Huang, G.J. Kunde, M. Lisa, W. Lynch, F. Mastinu, G. Margaglioti, P. Milazzo, C. Montoya, G. Peaslee, L. Phair, R. rui, C. Schwarz, M.B. Tsang, G. Vannini, C. Williams, "Reducibility and a new entropic term in multifragment charge distributions", Phys. Rev. C53, R5 (1996). 15. M. D'Agostino, P.F. Mastinu, P. Milazzo, M. Bruno, D.R. Bowman, P. Buttazzo, L. Celano, N. Colonna, J.D. Dinius, A. Ferrero, L. fiandri, C.K. Gelbke, T. Glaasmacher, F. Gramegna, D.O. Handzy, D. Horn, W.C. Hsi, M. Huang, I. Iori, G.J. Kunde, M. Lisa, W. Lynch, L. Manduci, G. Margagliotti, C. Montoya, A. Moroni, G. Peaslee, F. Petruzzelli, L. Phair, R. Rui, C. Schwarz, M.B. Tsang, G. Vannini, C. Williams, "Multifragment production in Au + Au at 35 MeV/U", Phys. Lett. B, 259 (1996). 16. I. Iori, "Heavy Ion Peripheral collisions at relativistic energy", Perspective in H.I. physics pag.105, World Scientific Press (1995). 17. Th. Rubehn, R. Bassini, M. Begemann-Blaich, Th. Blaich, A. Ferrero, C. Gross, G. Immè, I. Iori, G.J. Kunde, W.D. Kunze, V. Lindestruth, U. Lynen, T. Möhlenkamp, L.G. Moretto, W.F.J. Müller, G. Ocker, J. Pochodzalla, G. Raciti, S. Reito, H. Sann, A. Schüttauf, W. Seidel, V. Serfling, W. Trautmann, A. Trzcinski, G. Verde, A. Wörner, E. Zude, B. Zwieglinski, "Total and nuclear fission cross section of 238U at relativistic energies", GSI 96-11 - März (1996). 18. P.F. Mastinu, M. Beljacem, D.R. Bowman, M. Bruno, M. D'Agostino, J.D. Dinius, A. Ferrero, L. Fiandri, C.K. Gelbke, T. Glasmacher, F. Gramegna, D.O. Handzyl, D. Horn, W.C. Hsi, M. Huang, I. Iori, G.J. Kunde, M. Lisa, W. Lynch, G. Margagliotti, P. Milazzo, C. Montoya, A. Moroni, G. Peaslee, F. Petruzzelli, R. Rui, C. Schwarz, M.B. Tsang, G. Vannini, C. Williams, V. Latora, A. Bonasera, "Signal of a critical behaviour, in peripheral Au + Au collisions at 35 MeV/nucleon", XXXIV International Meeting on Nuclear Phys. - Bormio 96 - Ric. Sc. & Edu. Perm. Suppl. 106, pag. 110 (1996). 19. M. D'Agostino, A.S. Botvina, P. Milazzo, M. Bruno, G.J. Kunde, D.R. Bowman, L. Celano, N. Colonna, J.D. Dinius, A. Ferrero, L. Fiandri, C.K. Gelbke, T. Glasmacher, F. Gramegna, D.O. Handzyl, D. Horn, W.C. Hsi, M. Huang, I. Iori, M. Lisa, W. Lynch, L. Manduci, G. Margagliotti, P.F. Mastinu, C. Montoya, A. Moroni, G. Peaslee, F. Petruzzelli, L. Phair, R. Rui, C. Schwarz, M.B. Tsang, G. Vannini, C. Williams, "Statistical multifragmentation in central Au * Au collisions at 35 MeV/u", Phys. Lett. B 371, 175 (1996). 20. P.F. Mastinu, M. Beljacem, M. D'Agostino, M. Bruno, P. Milazzo, G. Vannini, D.R. Bowman, N. Colonna, J.D. Dinius, A. Ferrero, L. Fiandri, C.K. Gelbke, T. Glasmacher, F. Gramegna, D.O. Handzyl, D. Horn, W.C. Hsi, M. Huang, I. Iori, M. Lisa, W. Lynch, G. Margagliotti, C. Montoya, A. Moroni, G. Peaslee, F. Petruzzelli, R. Rui, C. Schwarz, M.B. Tsang, C. Williams, V. Latora, A. Bonasera, "Circumstantial evidence for critical behaviour in peripheral Au + Au collisions at 35 MeV/u", Phys. Rev. Lett. 76, 2646 (1996). 21. A. Schüttauf, W.D. Kunze, A. Wörner, M. Begemann-Blaich, Th. Blaich, D.R. Bowman, R.J. Charity, A. Cosmo, A. Ferrero, C.K. Gelbke, C. Gross, W.C. Hsi, J. Hubele, G. Immè, I. Iori, J. Kempter, P. Kreutz, G.J. Kunde, V. Lindenstruth, M. Lisa, W.G. Lynch, U. Lynen, M. Mang, T. Möhlenkamp, A. Moroni, W.F.J. Müller, M. Neumann, B. Ocker, G.F. Peaslee, J. Pochodzalla, G. Raciti, F. Rosenberger, T. Rubenhn, H. Sann, C. Schwarz, W. Seidel, V. Serfling, L.G. Sobotka, J. Stroth, L. Stuttge, S. Tomasevic, W. Trautmann, A. Trzcinski, B. Tsang, A. Tucholski, G. Verde, C.W. Williams, E. Zude, B. Zwieglinski, "Universality of spectator fragmentation at relativistic bombarding energies", GSI 96-26 Juni 96 - Nucl. Phys. A607, 457-486 (1996). 22. J. Pochodzalla, G. Immè, V. Maddalena, C. Nociforo, G. Raciti, G. Riccobene, F.P. Romano, A. Saija, G. Sfienti, G. Verde, M. Begemann-Blaich, S. Fritz, C. Gross, U. Kleinevoss, V. Lindenstruth, U. Lynen, M. Mahi, W.F.J. Müller, B. Ocker, T. Odeh, Th. Rubhen, H. Sann, M. Schnittker, C. Schwarz, V. Serfling, W. Trautmann, A. Wörner, E. Zude, T. Möhlenkamp, W. Seidel, W.D. Kunze, A. Schüttauf, G.J. Kunde, S. Gaff, H. Xi, R. Bassini, I. Iori, A. Moroni, F. Petruzzelli, A. Trzcinski, B. Zwieglinski, "The nuclear liquid-gas phase transition: present status and future perspectives", GSI 96-31 - Juli (1996). 23. G. Immè, V. Maddalena, C. Nociforo, G. Raciti, G. Riccobene, F.P. Romano, A. Saija, G. Sfienti, G. Verde, M. Begemann-Blaich, S. Fritz, C. Gross, U. Kleinevoss, U. Lynen, M. Mahi, W.F.J. Müller, B. Ocker, T. Odeh, M. Schnittker, C. Schwarz, V. Serfling, W. Trautmann, A. Wörner, T. Möhlenkamp, W. Seidel, W.D. Kunze, A. Schüttauf, J. Pochodzalla, G.J. Kunde, S. Gaff, R. Bassini, I. Iori, A. Moroni, F. Petruzzelli, A. Trzcinski, B. Zwieglinski, "Last minute from ALADIN, Temperature measurements in Au + Au reactions at relativistic energies", GSI 96-30 Juli (1996). 24. W.F.J. Müller, R. Bassini, H. Emling, M. Begemann-Blaich, Th. Blaich, A. Ferrero, S. Fritz, C. Gross, G. Immè, I. Iori, U. Kleinevoss, G.J. Kunde, W.D. Kunze, V. Lindenstruth, U. Lynen, M. Mahi, A. Moroni, T. Möhlenkamp, B. Ocker, T. Odeh, J. Pochodzalla, G. Raciti, T. Rubenhn, H. Sann, M. Schnittker, A. Schüttauf, C. Schwarz, W. Seidel, V. Serfling, J. Stroth, W. Trautmann, A. Trzcinski, G. Verde, A. Wörner, E. Zude, B. Zwieglinski, "Determination of critical exponents in nuclear systems", GSI 96-29 - le self-enrgy has been studied in semi-infinite nuclear matter with use of an effective interaction of strength determined self-consistently. The resulting damping width of a particle at the Fermi energy is found to display a linear dependence with temperature as a result of the coupling to surface excitation, while the effective mass shows an exponential decay. The same model indicates that the damping width of giant resonance (i.e. a correlated hole in the Fermi sea and a particle above the Fermi surface) is independent of temperature. The reason for this behaviour is two-fold: a) a particle or a hole at about few MeV from the Fermi energy displays a weak linear dependence, b) the corresponding contributions to the giant resonance damping width enter with opposite sign and essentially cancel out even the weak linear dependence. Rotational motion in hot nuclei. Rotational motion loses its coherence as a function of the nuclear internal excitation energy. The damping process does not proceed in a continous fashion, and scars of discrete rotational bands are found, inbedded in a background of damped rotatinal states. The complexity of the damping mechanism is revealed in the lineshape of the ridges in the *-* correlation spectrum. Damping width of double resonances. The damping width of the double dipole giant resonance of heavy nuclei excited in relativistic heavy ion collision has been calculated taking into account couplings to doorway staes containing surface vibrations. The resulting width of the double giant resonance is close to the value predicted by the harmonic model. Collective response of nuclei far from the stabiltiy valley. The nuclei 28O and 100Sn have been selected respectively as examples of neutron-rich and of proton-rich isotopes and their single-particle spectra, as well as their response to a quadrupole external field studied. While the response of 100Sn is quite close to that of 132Sn, that of 28O has a centroid which is much lower than that expected for giant quadrupole resonances in stable nuclei of similar mass number, and a width which is half determined by doorway coupling, and half by the coupling to the continuum, a mechanism which essentially plays no role in nucleai along the stability valley. (PierFrancesco Bortignon, Ricardo A. Broglia, Gianluca Colò, Erich Ormand, Enrico Vigezzi, Francesco Ghielmetti, Nicola Giovanardi, Marco Braguti) Recent Publications: 1. B. Lauritzen, P.F. Bortignon, R.A. Broglia, V.G. Zelevinsky, "Limiting Value for the Width Controlling the Coupling of Collective Vibratons to the Compound Nucleus", Phys. Rev. Lett. 74, 5190 (1995). 2. W. Huang, Z. Wang, P.F. Bortignon, R.A. Broglia, "Surface Effects on Particle Self- Energies ai Finite Temperature", J. Phys. Nucl. Part. Phys. 21, 965 (1995). 3. J. D'Avanzo, M. Lontano, E. Tomè, P.F. Bortignon, "Aplha Particle Stopping in a Dense Plasma", Nucl. Fusion 35, 210 (1995). 4. J. D'Avanzo, M. Lontano, E. Tomè, P.F. Bortignon, "Heavy-Ion Interaction in a Nonthermal Plasma with Two-Ion Correlation Effects", Phys. Rev. E52, 919 (1995). 5. M. Cinausero, P.F. Bortignon, et. al., "Giant Dipole Resonance in A ~ 40 Hot Nuclei From Coincidence Measurements", Zeit Phys. A352, 273 (1995). 6. T. Døssing, E. Vigezzi, "Cooling and diffusion in the *-decay of rotating nuclei", Nucl. Phys. A587, 13 (1995). 7. S. Leoni, B. Herskin, T. Døssing, P. Rasmussen, P. Bosetti, S. Frattini, M. Matsuo, N. Nica, E. Vigezzi, A. Atac, M. Bergstrom, A. Brockstedt, H. Carlsson, P. Ekstrom, F. Ingebretsen, H.J. Jensen, J. Jongman, G.B. Hagemann, R.M. Lieder, T. Lonnroth, A. Maj, B. Million, A. Nordlund, J. Nyberg, M. Piiparinen, H. Ryde, D.C. Radford, M. Sugawara, P.O. Tjøm, A. Virtanen, "The distribution of the rotational transition strength in warm nuclei studied through *-ray coincidences", Nucl. Phys. A587, 513 (1995). 8. G.L. Colò, M.A. Nagarajan, P. Van Isacker, A. Vitturi, "Isospin mixing in proton-rich N*Z nuclei", Phys. Rev. C52, R1175 (1995). 9. G.L. Colò, N. Van Giai, H. Sagawa, "Isovector properties of Skyrme-type effective interactions", Phys. Lett. B363, 5 (1995). 10. F. de Blasio, G. Lazzari, P.M. Pizzochero, R.A. Broglia, "Superfluidity and Thermal Response of Neutron Star Crust", Phys. Rev. D53, 4226 (1996). 11. F. Barranco, E. Vigezzi, R.A. Broglia, "Momentum Distribution in the Fragmentation of Halo Nuclei", Z. Phys. A356, 45 (1996). 12. P. Donati, N. Giovanardi, P.F. Bortignon, R.A. Broglia, "Damping of nuclear Motion in Hot Nuclei", Z. Phys. A356, 45 (1996). 13. P. Donati, P.F. Bortignon, R.A. Broglia, "Temperature Dependence of the Damping Width of Single-Particle States in Hot Nuclei", Z. Phys. A354, 249 (1996). 14. W.E. Ormand, P.F. Bortignon, R.A. Broglia, "Temperature Dependence of the Width of the Giant-Dipole Resonance in 120Sn and 208Pb", Phys. Rev. Lett. 77, 607 (1996). 15. N. Giovanardi, P.F. Bortignon, R.A. Broglia, W. Huang, "Temperature Dependence of the Coupling of Nucleons top the Nuclear Surface", Phys. Rev. Lett. 77, 24 (1996). 16. R.A. Broglia, T. Døssing, M. Matsuo, E. Vigezzi, P. Bosetti, A. Bracco, S. Frattini, B. Herskind, S. Leoni, P. Rasmussen, "Scars of Discrete Rotational Bands in Hot Nuclei", Zeit. Phys. A356, 259 (1996). 17. T. Døssing, B. Herskind, R.A. Broglia, A. Bracco, S. Leoni, M. Matsuo, E. Vigezzi, "Fluctuation Analysis of Rotational Spectra", Phys. Rep. 268, 1 (1996). 18. A. Bracco, F. Alasia, S. Leoni, E. Vigezzi, R.A. Broglia, "Nuclear Rotations", Cont. Phys. 37, 183 (1996). 19. G. Viesti, M. Lops, B. Fornal, D. Bazzacco, P.F. Bortignon, M. Cinausero, G. de Angelis, D. Fabris, E.M. Fiore, L. Fiore, E. Fioretto, N. Gelli, F. Lucarelli, S. Lunardi, G. Nebbia, V. Paticchio, G. Prete, C. Rossi Alvarez, "Probing the Giant Dipole resonance in the Compound Nucleus 156Er", Nucl. Phys. A604, 81 (1996). 20. F. Lucarelli, N. Gelli, P. Blasi, M. Cinausero, E. Fioretto, G. Prete, D. Fabris, G. Nebbia, G. Viesti, E.M. Fiore, L. Fiore, V. Paticchio, P.F. Bortignon, "High-Energy Gamma Rays Emission in Coincidence with Light Charged Particles from the 32S+74Ge reaction at 210 MeV", Nucl. Phys. A604, 81 (1996). 21. P.F. Bortignon, N. Van Giai, Comment on "Continuum Tamm-Dancoff Approximation Calculations for the Escape Widths of the Isobaric Analog State and Gamow-Teller Resonance in 208Bi", Phys. Rev. C54, 1 (1996). 22. A. Bracco, P. Bosetti, S. Frattini, E. Vigezzi, S. Leoni, T. Døssing, B. Herskind, M. Matsuo, "Microscopic simulations of * cascades in warm rotating nuclei", Phys. Rev. Lett. 76, 4484 (1996). 23. G.L. Colò, N. Van Giai, "Where is the non spin-flip isovector monopole resonance in 208Tl?", Phys. Rev. C53, 2201 (1996). 24. F. Ghielmetti, G.L. Colò, E. Vigezzi, P.F. Bortignon, R.A. Broglia, "Spectral line shape of exotic nuclei", Phys. Rev. C54, R2143 (1996). 25. E. Vigezzi, S. Frattini, P. Bosetti, A. Bracco, R.A. Broglia, T. Døssing, B. Herskind, S. Leoni, M. Matsuo, "Towards a Realistic Descritption of the Gamma-Quasicontinuum", in Proceedings of the Workshop on Heavy Ion Fusion: Exploring the Variety of Nuclear Properties, Padova 1994, Eds. A.M. Stefanini, G. Nebbia, S. Lunardi, G. Montagnoli, A. Vitturi, World Scientific, 149 (1995). 26. P.F. Bortignon, M. Braguti, D.M. Brink, R.A. Broglia, C. Brusati, F. Camera, W. Cassing, M. Caviniato, N. Giovanardi, F. Gulminelli, "On the Giant Dipole Resonance Excitation in Very Hot Nuclei", Nucl. Phys. A583, 101c (1995). 27. F. Ghielmetti, G.L. Colò, P.F. Bortignon, R.A. Broglia, E. Vigezzi, "Collective Response of Nuclei Far from the Stability Valley", in Proceedings of Nuclear Theorist Meeting, Cortona, Italy, 309 (1995). 28. N. Giovanardi, P.F. Bortignon, R.A. Broglia, "Properties in Semi-Infinite Nuclear Matter at Finite Temperature", in Proceedings of Nuclear Theorists Meeting, Cortona, Italy, 239 (1995). 29. B. Herskind, S. Leoni, T. Døssing, G.B. Hagemann, P. Bosetti, A. Bracco, S. Frattini, E. Vigezzi, M. Matsuo, "Towards complete spectroscopy in rapidly rotation nuclei", Proc. of the XXIX Zakopane School of Physics, Acta Phys. Pol. B26, 153 (1995). 30. W.E. Ormand, P.F. Bortignon, R.A. Broglia, "Temperature Dependence of the Width of the Giant Dipole Resonance in 120Sn and 208Pb", Nucl. Phys. A599, 341c (1996). 31. V. Yu Ponomarev, P.F. Bortignon, R.A. Broglia, E. Vigezzi, V.V. Voronov, "On Single and Double-Resonances in Spherical Nuclei", Nucl. Phys. A599, 341c (1996). Theoretical Studies of Hadron Physics. Effective Theories for Hadron: mesons are described as collective qq-modes in the Nambu-Jona- Lasinio model, where the pion corresponds to the Goldstone mode of the corresponding condensate. The **** decay is considered within this approach. A value * = 118 MeV is obtained, as well as a shift of the rho meson mass which is lovered by 64 MeV with respect to the RPA value. (Ricardo A. Broglia, Pierre Pizzochero, Norberto N. Scoccola, Alberto Polleri) Theoretical Studies of Nuclear Astrophysics. The research activity in Nuclear Astrophysic of the Nuclear Theory Group is mainly focused on the connections between the microscopic properties of dense and hot matter and the macroscopic properties of the astrophysical systems formed by such matter. Neutrino Astrophysics: neutrino absorption cross sections are calculated for different nuclei, which are good candidates for solar neutrino detectors (23Na, 40Ar, 81Br). The Gamow-Teller transitions to low-lying states are calculated using shell-model techniques for the lighter nuclei and developing RPA-type approaches for the heavier ones. In all cases, it is found that the inclusion of excited states enhances significantly the absorbtion cross section for solar neutrinos. Superfluidity in Neutron Stars: observations of the thermal emission from young neutron stars have the potential for constraining their structure and thence the underlying equation of state of dense matter. The thermal response of the crust of a neutron star to the rapid cooling of its core, however, depends critically on the superfluidity of matter in the crust. The pairing properties of matter in the inner-crust of a neutron star, where a Coulomb lattice of neutron-rich nuclei is permeated by a gas of unbound neutrons, are studied by making use of a semiclassical model to determine the spatial behaviour of the neutron pairing gap. The possible presence of unusual nuclear shapes in the deeper layers is also considered, and the specific heat of the non-uniform neutron fluid is calculated. It is found that taking into account the existence of a lattice of nuclei (in both spherical and unusual shape) in the sea of unbound neutrons increases significantly the diffusion times across the crust and hence the coooling times of the surface of the star, as compared to the standard scenario with a uniform neutron superfluid in the inner crust. Applications of these results to vortex trapping and pulsar glitches are presently under study. (PierFrancesco Bortignon, Ricardo A. Broglia, Pierre Pizzochero, Enrico Vigezzi, Marco Bianchetti, Mariella Quaglia, Luciano Viverit) Recent Publications: 1. W.E. Ormand, P.M. Pizzochero, P.F. Bortignon, R.A. Broglia, "Neutrino Capture Cross Section 40Ar and * decay at 40Ti", Phys. Lett. B345, 343 (1995). 2. F. De Blasio, G. Lazzari, P.M. Pizzochero, R.A. Broglia, "Superfluidity and Thermal Response of Neutron Star Crusts", phys. Rev. D53, 4226 (1995). Algebraic scattering theory (AST). In the framework of algebraic scattering theory (AST) coupled channel calcutations are performed for heavy-ion reactions near Coulomb barrier and the suitable algebraic potentials are discussed. (Lina Zuffi) Recent Publications: 1. R. Lichtenthäler Filho, M. Vaccari, A. Ventura, L. Zuffi, "Algebraic coupled-channel formalism for heavy ions near the Coulomb barrier", Proceedings of the International Conference "Inverse and Algebraic Quantum Scattering Theory", Sept. 3-7, 1996 - Balatonföldvar - Hungary (1996). Nuclear *-deacy. The theory of nuclear *-decay is discussed in the framework of interacting boson-fermion model (IBFM) and calculations are performed in different mass regions. (Lina Zuffi) Recent Publications: 1. G.. Maino, L. Zuffi, "Gamow-Teller *-decay of even-even nuclei in the U(5) limit of the Interacting Boson Model", Proceedings of the "5th International Spring Seminar on Nuclear Physics: New Perspectives in Nuclear Structure" - Ravello, Italy, May 22-26, 1995 ed. A. Covello, pag. 611 (1995). 2. G. Maino, S.G. Mashnik, S.A. Srnolyansky, L. Zuffi, "Bose-Fermi symmetries and weak interactions in nuclei", Proceeding of "9th International Symposium on Capture Gamma-ray Spectroscopy and Related Topics" - Budapest, 8-12 October (1996). Research in Quantal Size Effects in Free Clusters. Electronic structure of metal clusters: Shell and supershell structures in trivalent and noble metal clusters. Evolution of collective properties: Plasmons, electron detachment, evaporation and fragmentation as a function of cluster size. (Paolo Milani) Research in Synthesis and Characterization of Cluster Beams for Nanostructured Thin Film Deposition. Realization of high intensity cluster sources: Pulsed Arc Cluster Ion Sources. Synthesis of nanophase materials: Hyperthermal cluster beams deposition, synthesis of nanostructured carbon films from carbon clusters, martensitic phase (Ni-Ti alloys), metallization and coatings. Fullerite and novel forms of carbon: Synthesis of carbon nanostrucutres by laser-induced modification of fullerite, electronic properties of fullerite, graphitization of fullerenes, characterization of a-C and diamond-like films and coatings. (Paolo Milani) Recent Publications: 1. F. Meinardi, A. Paleari, M. Manfredini, P. Milani, "Raman characterization of amorphous carbon produced by fullerite laser-induced transformation", Solid State Commun. 93, 335 (1995). 2. M. Manfredini, P. Milani, "Photochemical etching of C60 single crystal". Appl. Phys. Lett. 66, 153 (1995). 3. S. Serra, M. Manfredini, P. Milani, L. Colombo, "Amorphization of fullerite crystals", Chem. Phys. Lett. 238, 281 (1995). 4. P. Milani, M. Manfredini, "Laser-Induced coalescence of C60 in the Solid State", J. Phys. Chem. 99, 16119 (1995). 5. M. Manfredini, C.E. Bottani, P. Milani, "Raman scattering characterization of amorphous carbon from photothermal oxidation of fullerite", J. Appl. Phys. 78, 5945 (1995). 6. G. Guizzetti, F. Marabelli, M. Patrini, G.F. Lorusso, V. Capozzi, A. Minafra, M. Manfredini, P. Milani, "Optical properties of monocrystalline and polycrystalline fullerene", The Physics of Semiconductors, ed. D.J. Lockwood, World Scientific, Singapore (1995) 369. 7. M. Manfredini, S. Serra, L. Colombo, P. Milani, "Structural and electronic properties of laser damaged fullerite crystal", in Science and Tecnology of fullerene materials MRS symp. proc. 359 Pittsburg, p. 475 (1995). 8. M. Manfredini, P. Milani, "Nano and micro structures of laser damaged fullerite crystal", in Science and Technology of fullerene material MRS symp. proc. 359 Pittsburg, p. 481 (1995). 9. P. Milani, M. Manfredini, "Laser and oxygen induced damage of C60 single crystal observed by SEM" in Science and Technology of fullerene material MRS symp. proc. 359 Pittsburg, p. 487 (1995). 10. G. Guizzetti, F. Marabelli, M. Patrini, G. Benedek, M. Manfredini, P. Milani, S. Sanguinetti, "Micro-F.T.I.R. and theoretical study of C60 single crystal vibrational modes", in Science and Technology of fullerene materials MRS symp. proc. 359 Pittsburg, p. 469 (1995). 11. P. Milani, P. Piseri, E. Barborini, S. Iannotta, "Pulsed vaporization sources for high efficiency production of metal clusters", Materials Sciences Forum, 195, 43 (1995). 12. P. Milani, M. Manfredini, "Surface periodic structures induced by pulsed laser irradiation of fullerite", Appl. Phys. Lett. 68, 1769 (1996). 13. M. Manfredini, C.E. Bottani, P. Milani, "Fullerenes as precursors of carbon based materials", Synthetic Metals 77, 81 (1996). 14. P. Piseri, S. Iannotta, P. Milani, "Parametrization of a two-stage mass spectrometer performing second-order space focussing", Int. J. Mass Spectrom. Ion Processes 153, 23 (1996). 15. M. Manfredini, C. Castoldi, G. Casamassima, P. Milani, "A simple method for the growth of C60 single crystals", Materials Science and Engineering B 39, 64 (1996). 16. C.E. Bottani, C. Mantini, P. Milani, M. Manfredini, A. Stella, P. Tognini, P. Cheyssac, R. Kofman, "Raman, optical absorption and trasmission electron microscopy study of size effects in germanium quantum dots", Applied Physics Letters 69, 2409 (1996). 17. M. Ferretti, M. Manfredini, A. Parisini, P. Milani, "Laser induced graphitization of Fullerite", Chemical Physics Letters 259, 432 (1996). 18. P. Milani, M. Manfredini, "Surface modifications of fullerite induced by pulsed laser irradiation", in Advanced Laser Processing of Materials-Fundamentals and Applications MRS symp. proc. 397, Pittsburg (1996) 485. 19. P. Piseri, E. Barborini, P. Milani, "Characterization of a pulsed cluster ion source for the production of metal clusters in molecular beams", in Metastable Phases and Microstructures, MRS symp. proc. 400, Pittsburg (1996) 59. Theoretical Studies of Atomic Cluster and Polymers. The word "cluster" is used to describe aggregates which are too large to be considered as molecules and too small to resemble a piece of a crystal. Their study provides insight into the evolution of matter from atom, to small particle and finally to solid. More importantly, it provides the elements needed in nanoscience. The techniques used to study the properties of clusters are expected to shed light on the interactions between the twenty aminoacids of which proteins are built. Such knowledge is essential in the study of protein folding, that is, in the study of how a protein of a specific sequence of aminoacids ends up in a unique configuration which, among other things, determines its biological functions. Metal Clusters: The optical properties of light mass sodium clusters have been calculated as a function of temperature. Time dependent local density theory together with termal fluctuations seem to provide an overall account of the experimental finding. Fullerenes: The study of the optical/uv spectra of deformed fullerenes, in particular C70, C90 and C110, provides evidence on the coupling of the electrons to the fullerene surface, and opens the possibility of producing nanowires and nanoantennas displaying metallic properties. Mutations in designed heteropolymer chains. The impact of mutations on the thermodynamics of protein-like heteropolymers has been studied. Our study suggest that protein strucutres may be remarkably tolerant to many mutations, as experimentally observed. It is likely that gradual changes may accumulate to provide new proteins with different structure and function. Our results also indicate that for each "wild type" native strucutre, there are many sequences which lead to the same conformation, indicating that "foldability" and "designability" are, to a large extent, equivalent concepts in the study of protein folding. (Ricardo A. Broglia, Federico Alasia, Paolo Arcagni, Gianluca Colò, Carlo Milani, Guido Tiana) Recent Publications: 1. F. Alasia, Ll. Serra, R.A. Broglia, N. Van Giai, E. Lipparini, H.E. Roman, "Self-Consistent Calculations in Spherical Metal Clusters with Realistic Pseudopotentials Uniformly Averaged", Phys. Rev. Lett. B52, 8488 (1995). 2. F. Alasia, R.A. Broglia, G.L. Colò, H.E. Roman, "Electromagnetic Response of Quasispheroidal Fullerene C70", Chem. Phys. Rev. 247, 502(1995). 3. G. Lazzari, H. Nishioka, E. Vigezzi, R.A. Broglia, "Pendulating Orbits in Large Metal Clusters", Phys. Rev. B53, 1064 (1996). 4. F. Alasia, J. Pacheco, R.A. Broglia, E. Roman, "Monolayer Metal Coverage of Fullerenes: the Optical Response", Z. Phys. D37, 277 (1996). 5. H.E. Roman, G.L. Colò, F. Alasia, R.A. Broglia, "Long Wavelength Optical Response of Incipient Fullerene Nanotubes", Chem. Phys. Lett. 251, 111 (1996). 6. C. Milani, C. Giambelli, F. Alasia, R.A. Broglia, G.L. Colò, H.E. Roman, "Evolution of the Plasmon Spectrum of C28Hn with the Passivation of Dangling Bonds", Chem. Phys. Lett. 258, 559 (1996). 7. C. Milani, C. Giambelli, H.E. Roman, F. Alasia, G. Benedek, R:A: Broglia, S. Sanguinetti, k. Yabana, "The Valence of Small Fullerenes", Chem. Phys. Lett. 258, 554 (1996). 8. G.L. Colò, R.A. Broglia, F. Alasia, H.E. Roman, Ll. Serra, "Giant Resonance in Nuclei and Fullerenes", Proceedings of the Adriatico Research Conference on Cooperative Effects in Many-Electron System and Their Response to External Fields, ICTP, Trieste, World Scientific (1996). NUCLEAR PHYSICS Seminars: W. Kühn (Università di Giessen - Germania, "Di-lepton spectroscopy with HADES", 1995. L. Moretto (Lawrence Berkeley Lab. - USA), "Charge correlation and dynamical instabilities in the multifragment emission process", 1995. F. Gulminelli (L.P.C. Universitè de Caen - Francia), "Temperatura dai rapporti isotopici? Applicazione di un modello di equilibrio termodinamico", 1996. R. Bougault (L.P.C. Univ. de Caen - Francia), "Hot expanding source in Xe+Sn central reactions", 1996. A. Gobbi (G.S.I. Darmstadt - Germania), "Central Au+Au collisions at SIS energie", 1996. L. Moretto (Lawrence Berkeley Lab. - USA), "Sub barrier fusion in hot nuclei", 1996. E. Shakhnovich (Department of Chemestry - Harvard), "Protein folding", 1996. CONFERENCES AND SCHOOLS 1. Nuclear Physics XXXIII International Meeting on Nuclear Physics Bormio (Italy) 23-27 Gennaio 1995 Proceeding in: Ricerca Scientifica ed Educazione Permanente Suppl. n 101 Prof. I. Iori XXXIV International Meeting on Nuclear Physics Bormio (Italy) 23-27 Gennaio 1996 Proceeding in: Ricerca Scientifica ed Educazione Permanente Suppl. n 102 Prof. I. Iori