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Witold Nazarewicz (UT/ORNL) University of Tokyo, May 27, 2005
Physics of Exotic Nuclei Witold Nazarewicz (UT/ORNL) University of Tokyo, May 27, 2005 Introduction Landscape/Playground Studies of Exotic Nuclei Exotic Nuclei and the Cosmos Radioactive Nuclear Beams Summary
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The Nobel Prize in Physics 2004 Gross, Politzer, Wilczek
The Nuclear Many-Body Problem radioactive beams electron scattering many body systems effective NN force heavy nuclei relativistic heavy ions few body systems bare NN force few body nucleon QCD quarks gluons vacuum quark-gluon soup QCD
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Energy Scales in Nuclear Physics
d _ g QCD scale 1000 MeV pion p+ ~140 MeV u d _ pion-mass scale 100 MeV deuteron ~3 MeV N-binding scale 10 MeV collective ~1 MeV
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Nuclear Landscape protons neutrons stable nuclei proton drip line
superheavy nuclei Nuclear Landscape 126 stable nuclei 82 r-process known nuclei proton drip line terra incognita 50 protons rp-process 82 neutron stars neutron drip line 28 20 50 8 28 neutrons 2 20 2 8
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Density Functional Theory self-consistent Mean Field
Theory: roadmap 126 82 r-process protons 50 rp-process 82 28 Density Functional Theory self-consistent Mean Field 20 50 8 28 neutrons 2 20 2 8 Ab initio Shell Model
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Ab initio: GFMC, NCSM, CCM (nuclei, neutron droplets, nuclear matter)
S. Pieper, ENAM’04 1-2% calculations of A = 6 – 12 nuclear energies are possible excited states with the same quantum numbers computed
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Diagonalization Shell Model
(medium-mass nuclei reached;dimensions 109!) Honma, Otsuka et al., PRC69, (2004) and ENAM’04 Martinez-Pinedo ENAM’04
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From Qualitative to Quantitative!
Nuclear DFT From Qualitative to Quantitative! Deformed Mass Table in one day!
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We need access to neutron- and proton-rich nuclei
Ab Initio The ultimate goal of the physics of nuclei is to develop a unified, predictive theory of nucleonic matter Density Functional Theory asymptotic freedom… What is the mechanism of nuclear binding? How do fission and fusion work? What are the phases and symmetries of nucleonic matter?
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Shells Nuclei Sodium Clusters 28 50 82 126 58 92 138 198 experiment
theory discrepancy 20 60 100 -10 10 Nuclei Number of Neutrons Shell Energy (MeV) 28 50 82 126 diff. -1 1 50 100 150 200 Number of Electrons Shell Energy (eV) 58 92 138 198 experiment theory deformed clusters spherical Sodium Clusters
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Change of Shell Structure in Neutron Rich Nuclei
Near the drip lines nuclear structure may be dramatically different. First experimental indications demonstrate significant changes No shell closure for N=8 and 20 for drip-line nuclei; new shells at 14, 16, 32
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What are the limits of atoms and nuclei?
Three frontiers, relating to the determination of the proton and neutron drip lines far beyond present knowledge, and to the synthesis of the heaviest elements Do very long-lived superheavy nuclei exist? What are their physical and chemical properties?
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Superheavy Elements
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S. Cwiok, P.H. Heenen, W. Nazarewicz
Superheavy Elements lifetimes > 1y S. Cwiok, P.H. Heenen, W. Nazarewicz Nature, 433, 705 (2005)
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Crazy topologies of superheavy nuclei…
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Neutron Drip line nuclei
HUGE D i f f u s e d PA IR ED 8He 4He 6He 5He 7He 9He 10He
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Outlaw nuclei of the nuclear borderland
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Skins and Skin Modes p n p n p n
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r Excitation spectrum of N2 molecule N Rotational Transitions ~ 10 meV
excited 1Su and 1Pu states + Diabatic potential energy surfaces for excited electronic configurations of N2 Rotational Transitions ~ 10 meV Vibrational Transitions ~ 100 meV Electronic Transitions ~ 1 eV
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Nuclear collective motion
Rotational Transitions ~ MeV Vibrational Transitions ~ MeV Nucleonic Transitions ~ 7 MeV What is the origin of ordered motion of complex nuclei? Complex systems often display astonishing simplicities. Nuclei are no exception. It is astonishing that a heavy nucleus, consisting of hundreds of rapidly moving protons and neutrons can exhibit collective motion, where all particles slowly dance in unison.
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Q1 Q E Q2 Q0 fission/fusion exotic decay heavy ion coll. shape
coexistence Q2 Q0 fission/fusion exotic decay heavy ion coll.
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We are all made of stardust
Based on National Academy of Science Report We are all made of stardust (debris from stellar explosions) Question 3 How were the elements from iron to uranium made ?
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(experiment and theory)
How does the physics of nuclei impact the physical universe? What is the origin of elements heavier than iron? How do stars burn and explode? What is the nucleonic structure of neutron stars? Mass known Half-life known nothing known RIA intensities (nuc/s) > 1012 1010 106 102 10-2 10-6 X-ray burst Masses and drip lines Nuclear reaction rates Weak decay rates Electron capture rates Neutrino interactions Equation of State Fission processes Nuclear Input (experiment and theory) p process s-process 4U 331 Frequency (Hz) 330 r process 329 Supernova E 328 327 10 15 20 Time (s) rp process Nova n-Star KS Crust processes stellar burning T Pyxidis protons neutrons
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r (apid neutron capture) process
The origin of about half of elements > Fe (including Gold, Platinum, Silver, Uranium) Supernovae ? Neutron star mergers ? Open questions: Where does the r process occur ? New observations of single r-process events in metal poor stars Can the r-process tell us about physics under extreme conditions ? Swesty, Calder, Wang
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The r-process neutron capture timescale: ~ 0.2 ms
(g,n) photodisintegration Equilibrium favors “waiting point” b-decay Neutron number Proton number Seed Rapid neutron capture neutron capture timescale: ~ 0.2 ms
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Nuclear Structure and Reactions
Nuclear Theory forces methods extrapolations low-energy experiments Nuclear Astrophysics
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Deciphering observations of Hubble, CHANDRA …
X-ray bursts ( ) 15 s Lines during bursts EXO Cottam, Paerels, Mendez 2002 331 330 329 328 327 Frequency (Hz) 10 15 20 Time (s) 4U ms burst oscillations Strohmayer Bhattacharyya et al. 2004 Deciphering observations of Hubble, CHANDRA … 18 18.5 time (days) (4U ) 6 h Superbursts
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Tests of the Standard Model
Parity violation studies in francium 126 82 Weak interaction studies in N=Z nuclei EDM search in radium 50 protons Specific nuclei offer new opportunities for precision tests of: CP and P violation Unitarity of the CKM matrix … 82 28 20 50 8 28 neutrons 2 20 How will we turn experimental signals into precise information on physics beyond the standard model? 2 8
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Worldwide RNB Effort EURISOL
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The Rare Isotope Accelerator
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QCD Complex Systems Cosmos subfemto… nano… Giga… femto… Physics
Origin of NN interaction Many-nucleon forces Effective fields femto… Physics of Nuclei How does complexity emerge from simple constituents? How can complex systems display astonishing simplicities? Complex Systems nano… Quantum many-body physics In-medium interactions Symmetry breaking Collective dynamics Phases and phase transitions Chaos and order Dynamical symmetries Structural evolution Cosmos Giga… Nuclear Astrophysics Origin of the elements Energy generation in stars Stellar evolution Cataclysmic stellar events Neutron-rich nucleonic matter Electroweak processes Nuclear matter equation of state How do nuclei shape the physical universe?
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Summary Connecting Nuclei with the Universe
The study of nuclei is a forefront area of science. It is this research that makes the connection between QCD phenomena, many-body systems, and the cosmos. What binds protons and neutrons into stable nuclei and rare isotopes? What is the origin of simple patterns in complex nuclei? Where and how did the elements from iron to uranium originate? Connecting Nuclei with the Universe
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