Exotica in Terra Incognita Saha Institute of Nuclear Physics, Kolkata C. Samanta April 8, 2003 IPR, India

Plan Of The Talk Origin of the elements in the universe Nuclei in uncharted territory How to make them Who are making them What we know about them, so far Exotic structures New Modes of Oscillation Curious decay preferences New magicity Applications in different branches of Physics April 8, 2003 IPR, India

April 8, 2003 IPR, India

Nucleosynthesis of the light elements Beyond 56Fe, fusion reactions do not release energy April 8, 2003 IPR, India

Nuclear Chart April 8, 2003 IPR, India

Normal Stable Nuclei Radius = 1.2 A1/3 A = Total number of neutrons and protons in the nucleus rn Density rp A=3 A=7 A=17 Radius (fm) Number of protons and neutrons are balanced: N/Z = 1 – 1.5 Separation energy of a nucleon is constant: Es = 6 – 8 MeV Nucleon density distributions are similar: ro = 0.15 fm-3 Protons and neutrons are homogeneously mixed: rn/rp  N/Z April 8, 2003 IPR, India

Halo Nucleus 11Li: Good Bye to Old Concepts! Radius ≠ 1.2 A1/3 rn / rp ≠ N / Z Normal Stable Nucleus April 8, 2003 IPR, India

Borromean Nuclei 11Li = 9Li +n+n 11Li-n 10Li Does not exist! 6He=4He+n+n 6He-n 5He Does not exist! Heraldic emblem of the medieval princes of Borromeo, Italy April 8, 2003 IPR, India

Schematic Diagram of Density Distributions in Normal, Skin and Halo Nuclei rn NORMAL rp Density rn-rp=0 Radius (r) SKIN HALO rn rn rp rp Radius (r) rn-rp > 0 Radius (r) rn-rp >> 0 April 8, 2003 IPR, India

What is an exotic nucleus? Normal Nucleus: Exotic Nucleus: 12C (carbon) 6 protons + 6 neutrons Stable, found in nature 22C (carbon) 6 protons + 16 neutrons Radioactive, at the limit of nuclear binding Characteristics of exotic nuclei: Excess of neutrons or protons, short half-life, neutron or proton dominated surface, low separation energy April 8, 2003 IPR, India

Rare Isotopes Away from the line of stabilities; 0.6 < N/Z < 4 Short lived; 10-12 sec < t1/2 < few seconds Low nucleon separation Energy; Es << 8 MeV Large radius ; r >> 1.2 A-1/3 (Ground state being close to continuum  Quantum tunneling) Exotic properties; skin, halo, large core, …..? April 8, 2003 IPR, India

How to make these rare isotopes? Transfer reactions (light nuclei) Fusion-evaporation (proton dripline) Fission (neutron dripline) Fragmentation Target fragmentation Projectile fragmentation April 8, 2003 IPR, India

Transfer Reactions April 8, 2003 IPR, India

Fusion Evaporation 292 MeV 54Fe + 92Mo  146Er(p4n)141Ho 402 MeV 78Kr + 58Ni  136Gd(p4n)131Eu A.A. Sonzogni et al., Phys. Rev. Lett. 83 1116 (1999) D. Seweryniak et al., Phys. Rev. Lett. 86 1458 (2001) April 8, 2003 IPR, India

Fission K.H. Schmidt et al., Model predictions of the fission-product yields for 238U (2001) April 8, 2003 IPR, India

Target Fragmentation Random removal of protons and neutrons from heavy target nuclei by energetic light projectiles (pre-equilibrium and equilibrium emissions). April 8, 2003 IPR, India

Projectile Fragmentation Random removal of protons and neutrons from heavy projectile in peripheral collisions hot participant zone projectile fragment projectile target Cooling by evaporation. projectile fragment April 8, 2003 IPR, India

Techniques 1) ISOL 2) Fragmentation 3) Reactors p,d,t,… heavy ions high energy beam RIB (low energy) Accelerator, Storage,…. Thick target 2) Fragmentation High energy heavy ion beam RIB (high energy) Spectrometers,… Target 3) Reactors Fission products (neutral, 1+charge state) Thermal neutrons RIB (low energy) Accelerator, Storage,…. Thin fissile target High charge state breeder April 8, 2003 IPR, India

Definitions/Numbers 1pnA, 80 MeV/nucleon, 18O, 8+ Energy Energy per nucleon: 80 MeV Total energy (80 A): 1440 MeV Momentum: 7096 MeV/c Velocity: 11.7 cm/ns 0.39 c Rigidity: (p/q) 2.96 Tm Beam Intensity Particle Current: 1pnA Electrical Current: 8enA Particles: 6.25x109/s Power: 1.44W April 8, 2003 IPR, India

April 8, 2003 IPR, India

New physics from Rare Isotopes Exotic shapes New Magicity New modes of oscillation New modes of decay New stability island beyond the sea of instability April 8, 2003 IPR, India

Proton halo Neutron halo Nuclei Nuclei 8B (1p) 6He (2n) 17F (1p, 1st ex st) 11Li (2n) 17Ne (2p) 11Be (1n), 14Be (2n) 23Al (1p) 17B (2n) 19C (1n) April 8, 2003 IPR, India

We would not exist! Magicity Atomic Magic Numbers : 2, 10, 18, 36 …. Inert gases: He (Z=2), Ne (Z=10), Ar (Z=18), Kr (Z=36) Nuclear Magic Numbers: 2, 8, 20, 28, 50, 82… Abundant He(Z=2), O(Z=8), Ca(Z=20), Ni(Z=28), Sn (Z=50), Pb(Z=82) What would have happened if the magic numbers were the same? We would not exist! April 8, 2003 IPR, India

Shell Model & Nuclear Magic Numbers April 8, 2003 IPR, India

New Magicity in Nuclei Loss of magicity: Experiment: [PRL 85, 266 (2000)] N=8 (Z=4), N=20 (Z=12) Theory: N=82 (Z< 48) Z=82 (N~107) C.Samanta and S.Adhikari, Phys. Rev. C 65, 037301 (2002) C. Samanta, Jour. Heavy Ion Phys (in press) April 8, 2003 IPR, India

Novel Structure Enlarged Core – rapid movement of nuclear shells in nuclei away from the line of stability gives rise to new shell closure at N=16. Experimental Evidence of Core Modification in the Near Drip-Line Nucleus 23O, Rituparna Kanungo et al., Phys. Rev. Lett.88, 142502 (2002) Current Science News Headlines http://www2b.abc.net.au/science/k2/stn-old/archive2002/posts/ March/topic669879.shtm April 8, 2003 IPR, India

April 8, 2003 IPR, India

Modes of Oscillations Giant Pygmy S t r e n g h Excitation Energy April 8, 2003 IPR, India

Is the 1.3 MeV excited state of 11Li a signature of pygmy resonance? R. Kanungo and C. Samanta, Jour. Phys. G: Nucl. Part. Phys.24, 1611(1998) April 8, 2003 IPR, India

Resonance or, Non-resonance Breakup? D. Gupta et al, Nucl. Phys. A 683,3 ( 2001); Hottest Paper in NPA http://www.elsevier.com/gej-ng/29/35/show/Products/NPE/npa_hottest.htt April 8, 2003 IPR, India

b-stable nuclei V(r) b+ b- r protons neutrons n drip line nuclei V(r) p drip line nuclei V(r) r r b- b+ protons neutrons protons neutrons April 8, 2003 IPR, India

Two Proton Decay – a new mode of decay! Researchers have monitored Ne-18 decay through one of the modes illustrated above. They believe they have finally detected the elusive dual-proton (He-2)decay, rather than democratic emission. The third mode, sequential proton emission, is not possible for the excited state of neon formed in a recent Oak Ridge National Laboratory experiment. Reported by: J. Gómez del Campo et al, Physics Review Letters, 1 January, 2000. April 8, 2003 IPR, India

April 8, 2003 IPR, India

Heavy Nuclei Element Year Place 106 (Seaborgium) 1974 LBL, USA & JINR, Dubna 107 (bohrium) 1981 GSI, Darmstadt, Germany 108 (hassium), 1984 GSI 109 (meitnerium) 1982 GSI 110 (ununnilium) 1994 GSI (A=269) 111 (unununium) 1994 GSI 112 (ununbium) 1996 GSI (30 x 10-6 s) 113 (ununtrium) (Not made yet) 114 (ununquadium) 1999 FLNR (N=184 not reached) 115 (ununpentium) (Not made yet) 116 (ununhexium) 1999-2000 FLNR April 8, 2003 IPR, India

a-decay chain to identify SHE April 8, 2003 IPR, India

Where is SHE? Production of longer lived neutron rich isotopes Connection to newly synthesized elements April 8, 2003 IPR, India

Application of Rare Isotopes Nuclear Physics Astrophysics Surface Science Medicine April 8, 2003 IPR, India

An illustration of how radioactive probe atoms implanted in a solid can act as "spies" on their microscopic environment. The properties of the probe atom are modified by the local microscopic environment and that information is carried away by the radiation emitted in the radioactive decay that follows. April 8, 2003 IPR, India

Medical Application Combining an RI beam and the PET allows simultaneous diagnosis and treatment of cancers. A test experiment of this combination using a 11C beam demonstrates that the beam irradiation is possible while monitoring the stopping location inside an object within a few mm accuracys. This technique is expected to be applicable to other medical fields than the cancer treatment and to fields other than medicine in the future. April 8, 2003 IPR, India

Upcoming RIB Facilities - Worldwide RIKEN (Japan) Cyclotron – 400-600 MeV/u Multi-Storage Rings Status: Phase I construction started RIA (USA) Superconducting Linac – 400 MeV/u Isol/In-Flight hybrid; no storage rings Status: Proposed (NSAC priority) GSI project: High Energy (1.5 GeV/u) Luminosity, Purity, Efficiency Synchroton <=> Storage Rings optimal choice!! April 8, 2003 IPR, India

T H A N K Y O U April 8, 2003 IPR, India

April 8, 2003 IPR, India

Nucleosynthesis of the light elements Prior to about one second after the Big Bang, matter - in the form of free neutrons and protons - was very hot and dense. As the Universe expanded, the temperature fell and some of these nucleons were synthesised into the light elements: deuterium (D), helium-3, and helium-4. Theoretical calculations for these nuclear processes predict, for example, that about a quarter of the Universe consists of helium-4, a result which is in good agreement with current stellar observations. The heavier elements, of which we are partly made, were created later in the interiors of stars and spread widely in supernova explosions. April 8, 2003 IPR, India

Borromean Heraldic emblem of the medieval princes of Borromeo, Italy 4He, 6He, 8He, 10He exist, but 5He, 7He, 9He do not. 11Li, 9Li exist but 10Li does not. April 8, 2003 IPR, India

Rare Isotopes Away from the line of stabilities; 0.6 < N/Z < 4 Short lived; 10-12 sec < t1/2 < few seconds Low nucleon separation Energy; Es << 8 MeV Quantum tunneling effect; r > ro A-1/3 Exotic properties; skin, halo, large core, …..? April 8, 2003 IPR, India

THE HOT BIG BANG MODEL About ten billion years ago, the Universe began in a gigantic explosion - the Hot Big Bang! Its subsequent evolution from one hundredth of a second upto the present day can be reliably described by the Big Bang model. This includes the expansion of the Universe, the origin of light elements and the relic radiation from the initial fire all , as well as a framework for understanding the formation of galaxies and other large-scale structures. In fact, the Big Bang model is now so well-attested that it is known as the standard cosmology. April 8, 2003 IPR, India

April 8, 2003 IPR, India

April 8, 2003 IPR, India

106 (Seaborgium) 1974 Lawrence-Berkeley Laboratory, USA Element Year Place 106 (Seaborgium) 1974 Lawrence-Berkeley Laboratory, USA Joint Institute for Nuclear Research, Dubna,Moscow 107 (bohrium), 1981 Gesellschaft für Schwerionenforschung 108 (hassium), 1984 109 (meitnerium) 1982 (GSI), Darmstadt, Germany 110 (ununnilium) 1994 (A=269) 111 (unununium) 1994 112 (ununbium) 1996 (30 x 10-6 s) 113 (ununtrium) (NOT MADE YET) Finally near the sea- shore of where SHE (Z = 114, N= 184) Lives 114 (ununquadium) 1999 Flerov Laboratory of Nuclear Reactions, (30 Seconds) JINR(US-Russia Joint Venture) Pu-244 supplied by LBNL. Dubna made two isotopes of the element, one had 175 neutrons, the other had 173 neutrons, N=184 not reached yet 115 (ununpentium) (NOT MADE YET) 116 (ununhexium) 1999-2000 Flerov Laboratory of Nuclear Reactions, JINR 117 (ununseptium) (NOT MADE YET) 118 (ununoctium) 1999 Lawrence Berkeley National Laboratory Laboratory in California On July 27, 2001, results retracted (Physical Review Letters) April 8, 2003 IPR, India

Giant Dipole Resonance, Soft-Dipole Resonance and Spin Dipole Resonance April 8, 2003 IPR, India

Neutron Halo/Skin Nuclei April 8, 2003 IPR, India

Isospin Tz = (N-Z)/2 Neutron rich Proton rich A = 21 A 21 C 6 15 Z N 21 21 21 21 21 21 21 21 C N O F Ne Na Mg Al 6 15 7 14 8 13 9 12 10 11 11 10 12 9 13 8 T Z +9/2 +7/2 +5/2 +3/2 +1/2 –1/2 –3/2 –5/2 Neutron rich Proton rich April 8, 2003 IPR, India

New Magicity in Nuclei Loss of magicity: Experiment: [PRL 85, 266 (2000)] N=8 (Z=4), N=20 (Z=12) Theory: N=82 (Z< 48) Z=82 (N~107) C.Samanta and S.Adhikari, Phys. Rev. C 65, 037301 (2002) T.Otsuka et al., Phys. Rev. Lett. 87, 082502 (2001) A. Ozawa et. al., Phys. Rev. Lett. 84, 5493 (2000) April 8, 2003 IPR, India