Heavy-Ion Binary Reactions as a Tool for Detailed Gamma Spectroscopy in Exotic Regions Silvia Leoni University of Milano & INFN

LOI Collaboration AGATA- PRISMA collaborations Milano University and INFN A. Bracco, G. Benzoni, N. Blasi, F. Camera, F. Crespi, S. Leoni, B. Million, O. Wieland et al. P.F. Bortignon, G.Colò, E. Vigezzi et al. Legnaro INFN Laboratory L.Corradi, G. DeAngelis, E. Fioretto, D. Napoli, A. Stefanini, J.J. Valiente-Dobon, et al. Padova University and INFN D. Bazzacco, E. Farnea, S. Lenzi, S.Lunardi, G. Montagnoli, D.Montanari, F.Scarlassara, C.Ur, et al. Torino University and INFN G. Pollarolo IFIC, CSIC-University of Valencia, Spain A. Gadea, … Krakow, Poland A. Maj, P. Bednarczyk, B. Fornal, M. Kmiecik, M. Ciemala et al., Ruder Boskovic Institute, Zagreb S. Szilner, T. Mijatovic et al. AGATA- PRISMA collaborations

Multi-Nucleon Transfer Reactions as a TOOL to study n-rich nuclei CLARA/AGATA–PRISMA campains @ LNL since 2004- … Structure of moderately n-rich nuclei using most n-rich beams by PIAVE-Tandem-ALPI (5-10 MeV/A) 48Ca 40Ar 36S 26Mg 64Ni 70Zn 82Se 96Zr 136Xe 48Ca 66Ni 64Ni 46Ca Multi-nucleon transfer A~50 48Ca + 64Ni @ 6MeV/A

CLARA (ex-EUROBALL)/AGATA – PRISMA setup Legnaro National Laboratory INFN (Italy) PRISMA ΔΩ = 80 msr ΔZ/Z  1/60 ΔA/A  1/190 Energy acceptance ±20% Bρ = 1.2 Tm CLARA (now AGATA) 25 EUROBALL HpGe Clover ~3 % @ Eγ= 1.3 MeV 2 p solid angle 3 rings at 100°, 130°, 150° High-Efficiency g - particle coincidence Measurements

First Excited States of Exotic Nuclei A & Z identification 64Ni + 238U @ 6.3 MeV/A Cr (-4p) Fe (-2p) S. Lunardi et al., PRC76(2007)034303 N. Marginean et al., PLB633(2006)696 Shape Evolution in Cr and Fe isotopes -2p+2n -4p +2p +1p -1p -2p -3p -4p -5p -6p Beams ~ 109 pps

Complete g-Spectroscopy: Ip and B(El) Plunger lifetime 48Ca + 64Ni @ 6 MeV/A Angular Distribution and Polarization 49Ca E1 E2 7/2- 9/2+ 3-p3/2 : coupling octupole Phonon - single particle 7 Wu Tentative Ip 0.05 Wu MNT Reactions: Strong SPIN Alignment perpendicular to reaction plane D. Montanari et al., PLB697(2011)288 and J.J. Valiente-Dobon et al., PRL102(2009)242502

FIRST EXAMPLE of Multi-Nucleon transfer with RIB 24Ne + 208Pb @ 7.9 MeV/A EXOGAM + VAMOS SPIRAL Beam 24Ne ~ 1.5 105 pps Study of Reaction Dynamics and First excited states mostly in ONE nucleon transfer channels G.Benzoni, F.Azaiez et al., EPJA45(2010)287 24Ne 25Ne +1n 23F -1p 2+  0+ Semiclassical model GRAZING gives reasonable agreement also for reactions with radioactive beams G. Pollarolo. A.Winther, Nucl.Phys.A594 (1995)203

Multi-Nucleon transfer with SPES beams Physics Cases with 108-109 pps 1 - g spectroscopy around 132Sn 2 - r-process nuclei beyond N=50 Multi-Nucleon transfer with SPES beams @ 5-10 MeV/A SIMILAR/BETTER quality as today experiments (with 109 pps)  factor  3 higher detection efficiency (CLARA GALILEO/AGATA)  factor 3 longer beam time (1 week 3 weeks)

CASE 1: g spectroscopy around 132Sn STUDY OF Single particle states particle-phonon couplings high spins Ip, B(El) Z=50 Complementary to Fission and b-decay Coulomb excitation Transfer with light targets (d,p), (d,t), … N=82 10 mb 1 mb SPES Beams 130Sn 1.6 108 131Sn 6.8 107 132Sn 3.1 107 133Sn 2.8 106 134Sn 5 105 129In 1.1 105 130In 1.5 104 131In 2.8 103 132In 1.9 103 133In - 128Cd 2.9 103 129Cd 2.5 102 130Cd GRAZING calculations Conservative estimates for more than 1 nucleon transfer

FOCUS on Particle-Phonon Coupled States Favourable population by Heavy-Ion Reactions excited core (phonon) Coupling with 1 particle - effective single particle levels - coupling strength Coupling with 2 particles - core + 2 particles model - physics of pairing Near DOUBLY MAGIC nuclei M.B. Tsang et al. PRL102(2009)062501 Ni ±40% (Theory) (EXP) Key Ingredients for understanding of Quenching of Spectroscopic Factors Anharmonicity of vibrational spectra Damping of Giant Resonances, … SOURCE OF DISCREPANCY with SHELL MODEL: CORE Excitations  Need of CORRELATIONS only partially included in Shell Model

132Sn – 133Sn Collective Properties of 132Sn: 208Pb 132Sn Spectroscopic factors Collective Properties of 132Sn: 2+: E = 4041 keV, B(E2) = 7.2 Wu 3-: E = 4352 keV, B(E3) > 7 Wu (d,p): 132Sn + CD2 K.L. Jones et al., Nature, 465(2010)454 Complemenary INFOs from MNT Single particle states in 133Sn: Low beam Intensity: ~ 105 pps Extraction of SF (~ 30% error)

131In – proton hole states 132Sn G.Colò and P.F.Bortignon pure M.Gorska et al., PLB672(2009)313

130Cd – 2 proton holes states 220 ns Tentative Ip assignment Tentative B(El) values Missing levels Strength of PAIRING interaction SHELL quenching below 132Sn GSI: Projectile fragmentation 136Xe (750 MeV/A) + Be A. Jungclaus et al., PRL99(2007)132501

Systematic Study of PVC states around magic/doubly-magic nuclei RESEARCH LINE: Systematic Study of PVC states around magic/doubly-magic nuclei Coupling strength Dependence on Fermi Surface Asymmetry (N/Z) Up to now: Scarce Information Mostly in Heavy-Masses 209Bi: Bohr & Mottelson, Vol. II. 209Pb: P. Kleinheinz et al.,PRL48(1982)1457 207Pb: N. Pietralla et al., PLB681(2009)134 A ~ 200 A ~ 150 147Gd, 147Tb: P. Kleinheinz et al.,PRL48(1982)1457; P. Kleinheinz, Physica Scripta 24(1981)236. More recently: Evidence for PVC in A~50 Nuclei 49Ca: 9/2+ @ 4017 keV = 3-  p3/2 47Ca: 11/2+ @ 3999 keV = 3-  f-17/2 … Robustness of Collectivity of magic (light) core …

Experimental Signature Multiplet of States: |l-j|  I  l+j B(El) of phonon 3/2+ 9/2+ 3/2- 0.0 0+ 0.0 7/2+ 3- 4.507 5/2+ E [MeV] 2 3 4 48Ca B(E3) 6.8 ± 1.0 Wu 3-  p3/2 7 Wu 49Ca Energy Split: Coupling strength Nuclear Force 48Ca (Z=20,N=28) (n,g) proposal at ILL Grenoble  3/2+ and 5/2+ Phys. Lett. B697(2011)288 Phys. Rev. C85(2012)044301

Theoretical Description PHENOMENOLOGICAL Particle-phonon WEAK coupling calculations (Bohr & Mottelson) SLy5 - LNS p 1d3/2 1f7/2 0.82 0.64 2s1/2 1f7/2 0.13 0.29  1f7/2 1g9/2 0.01 0.02 “SIMPLE”  MACROSCOPIC CORE Vibration Transition Densities 48Ca: 3- RPA calculations 3-  p3/2 [l  j1]I 49Ca Multiplet of States 9/2+, 7/2+, 5/2+, 3/2+ Energy Shift Lowest order Perturbative Contributions wl , B(El) → Exp. Values s.p. Energies e(j1), e(j2) → HF – SkX

Energy Density Functional Theoretical Description PHENOMENOLOGICAL Particle-phonon WEAK coupling calculations (Bohr & Mottelson) MICROSCOPIC Calculations based on SELF-CONSISTENT Scheme Energy Density Functional RPA microscopic Vph G. Colò, H. Sagawa, P.F. Bortignon, PRC 82, 064307 (2010). Hartee-Fock with Veff → short-range correlations included Particle-Vibration coupling on top → same Hamiltonian or EDF NO approximation in the vertex EXACT treatment of COUPLING use of WHOLE phonon wave function 3-  p3/2 [l  j1]I 49Ca Multiplet of States 9/2+, 7/2+, 5/2+, 3/2+ Energy Shift Lowest order Perturbative Contributions wl , B(El) → Exp. Values s.p. Energies e(j1), e(j2) → HF – SkX Need of More Experimental Input

WORK in PROGRESS: Study of PVC states around Ni isotopes [l  j1]I Multiplet of States 9/2+, 7/2+, 5/2+, 3/2+ 3- B(E3)~15Wu 64,66Ni (Z=28,N=36,38) Superfluid Core in n p coupling pp3/2- Approved Experiment 64Ni(7Li,)65Cu Tandem-Bucarest S. Leoni et al. FAST TIMING B(E3)~??? Wu Existing Data 64Ni(,p)67Cu N. Marginean et al. FAST TIMING t(9/2+)~150 ps B(E3)~17(2)Wu

66Ni (Z=28,N=38) : Superfluid Core Single Particle Levels Pairing Strength Including Pairing … Coupling with proton WORK in PROGRESS … S. Bottoni, G. Colò, P.F. Bortignon, …

CASE 2: r-process nuclei beyond N=50 Shape changes with N number subshell N=56 N=50 SPES Beams 90Rb 1.9 109 91Rb 92Rb 1 109 93Rb 6.8 108 94Rb 2.7 108 - 2p - 1p r-process - 3p 94-96Kr 90-92Br Only masses - 4p 87-90Se 86-88As

Importance of Nuclear Deformation difficoult to extrapolate for r-process b-decay half-lives and neutron emission probabilities are different in DEFORMED and SPHERICAL nuclei tb SPH ~ 7 x tbDEF PnSPH ~ 0.5 x PnDEF Large uncertainty in r-process location difficoult to extrapolate to more exotic regions P. Moller et al., Phys. Rev. C67, 055802 (2003) and ref. therein.

APPROVED REX-ISOLDE Proposal Gamma spectroscopy of n-rich 95,96,97Rb nuclei by the incomplete fusion reaction of 94Kr on 7Li Spokepersons: B. Fornal and S. Leoni particle emission 94Kr + 7Li → 97Rb + a ELAB = 3 MeV/nucleon Sa  2.5 MeV Production of the excited 97Rb Subsequent evaporation of one or two neutrons  96Rb and 95Rb population of only one state at ~14.5 MeV  factor of 10-20 more expected 35-75 mb for 97Rb (and 95Rb) 232 MeV 7Li a 6Li t MINIBALL + Si Telescope TEST of reaction mechanism Spectroscopy of n-rich 95-97Rb  expected population of NON-yrast states

to populate Highly-excited dipole states CONCLUSIONS Multi-Nucleon Transfer at 5-10 MeV/A are powerfool tool to reach exotic nuclei with most intense SPES beams 130-132Sn and 90-92Rb g spectroscopy around 132Sn (PVC states) r-process nuclei beyond N=50 WORK in Progress: Systematic investigation of Particle-Phonon Couplings in different MASS regions: Ca, Ni, … Theoretical Investigation by Phenomenological/Microscopic Models Complementary to SHELL MODEL Comparison with Other Rection Mechanisms to populate Highly-excited dipole states  preparatory work is needed excitation function with stable beams 5-10-15 MeV/A

Thank you for the attention

Spectroscopic Factors Nature and Occupancy of single-particle orbits Interplay Single-Particle and Collectivity  Crucial test of Shell Model and Interactions Source of discrepancies Core excitations State fragmentation M.B. Tsang et al. PRL102(2009)062501 Ni ±40% (Theory) (EXP) A. Gade et al. PRC77(2008)044306 Dependence on Fermi Surface Enhanced CORRELATIONS in Strongly bound valence nucleons

HOT topic in Nuclear Physics Evolution of Shell Structure with N/Z Search for Shell closures, Magic Numbers Nature Effective Nuclear Force: 2-body, 3-body, … Doubly Magic Nuclei Near to Magic Nuclei (1 and 2 nucleons away) Among EXPERIMENTAL TOOLS Coulex Collectivity B(E2), B(E3), … Knock-out, transfer reactions, … Spectroscopic Factors Purity of nuclear states Single particle (SF 1) Correlations (SF <1) HOT topic in Nuclear Physics