Frontiers in Nuclear Physics
Brad Sherrill, NSCL Director
• Introduction
• “Big picture” challenges for nuclear science
• Rare isotopes
• The specific challenges
– Modeling Nuclei
– The origins of atoms
– Forces in nuclei
– Uses of isotopes
• Summary
Sherrill EBSS 2015
1
Multiple choice question
Where do the majority of gold atoms come
from?
A.
B.
C.
D.
E.
They were mostly made by human activity
They were produced in neutron star collisions
They were produced in supernovae
They were produced in stars like our sun
We are not sure where they are made
Sherrill EBSS 2015
2
When did people first create gold atoms
from something else?
• 1924 Editors of Scientific American “Gold can be extracted from mercury,
but mercury cannot be transmuted into gold.”
• “It was not until 1941 that gold was actually prepared from a base metal. By
bombarding mercury with fast neutrons, Sherr, Bainbridge, and Anderson
obtained three radioactive isotopes of gold. Even that did not fulfill the
dream of the alchemists; the gold was radioactive and the process did not
produce wealth; it consumed it.” A Philatelic Ramble Through Chemistry
(Heilbronner and Miller; Verlag 1998)
Sherrill EBSS 2015
3
2012 Decadal Study of Nuclear Physics –
National Research Council
Four overarching questions for the field
of nuclear science:
(1) How did visible matter come into
being and how does it evolve?
(2) How does subatomic matter
organize itself and what phenomena
emerge?
(3) Are the fundamental interactions
that are basic to the structure of matter
fully understood?
(4) How can the knowledge and
technological progress provided by
nuclear physics best be used to benefit
society?
http://www.nap.edu/catalog/13438/nuclear-physics-exploring-the-heart-of-matter
Sherrill EBSS 2015
4
The Major Nuclear Science Facilities –
Relativistic Heavy Ion Collider
Sutdy of the phases of nuclar matter
J. Anderson
Production and study of new
states of QCD matter
https://www.ntnu.edu/physics/theoretical/thermqcd
Sherrill EBSS 2015
5
Jefferson Laboratory – 12 GeV Upgrade
some examples of science, more to come
Semi-inclusive deep inelastic scattering
http://arxiv.org/pdf/0812.2208.pdf
http://www.usqcd.org/hadron.html
Sherrill EBSS 2015
6
After FRIB the next major facility will be
the Electron Ion Collider (e+p 100 GeV)
Science Topics:
• Proton Spin
• Motion of quarks and gluons in
the proton (and nuclei)
• QCD matter at an extreme
gluon density
• Tomographic images of the
proton (and nuclei)
• Quark hadronization
EIC White Paper
http://arxiv.org/pdf/1212.1701v3.pdf
Sherrill EBSS 2015
7
Fundamental Symmetries and Neutrinos
• Is the neutrino its own anti-particle (Majorana particle)?
No neutrinos in
the final state –
Lepton number
violoated
Mixing of
neutrinos
shows mass
differences
Several tons of
material is
required to
push the limits
Sherrill EBSS 2015
8
Nuclear Physics explores the structure
and phases resulting from QCD
QCD of nucleons (and nuclei) – JLAB/EIC
Picture
from
Stephan
Scherer
QCD liquid and nucleons - RHIC
Picture
from
BNL
QCD Lagrangian
QCD in nuclei FRIB
Sherrill EBSS 2015
9
How do we understand nuclear
structure?
• Oral history that when the Schrodinger equitation was published
Dirac declared that chemistry had come to and end – its content
is contained in one equation (Walter Kohn Nobel Lecture 1999)
• Dirac added: too bad this equation is to complicated to allow
solution in most cases
• In nuclear physics we have a similar situation. We believe the
underlying force can be described by QCD and the general form
of the QCD Lagrangian (more generally the by the Standard
Model of particle physics)
• Too bad this equation is to complicated to allow solution in most
cases
• Challenge – find the appropriate techniques to model nuclei,
preferably grounded in QCD (but we will take whatever works)
Sherrill EBSS 2015
10
The light hadron spectrum from Lattice QCD
Dürr, Fodor, Lippert et al., Science 322 (2008) 1224
Neutron-Proton Mass Difference: Sz. Borsanyi, et al., Science 27 March 2015:
vol 347 p 1452
Sherrill EBSS 2015
11
What a proton really looks like
• 99% of the visible mass of the universe is in protons and neutrons
(nucleons)
• Only a few percent of the mass of the proton (5%) is from the quark mass
(LQCD is now able to demonstrate a heavy proton mass from light quarks;
Dürr et al. Science 322 (2008))
Frank Lee http://home.gwu.edu/~fxlee
Sherrill EBSS 2015
12
A Challenge for Nuclear Science
• We want to model physical
phenomena that are the result of the
strong force
• This includes understanding atomic
nuclei, hadrons, QGP, …
• We have made remarkable progress
in modeling hadrons – Nobel prize
in 2004 Gross, Politzer, Wilczek ;
LQCD calculation of nucleon and
meson masses (Dürr, Fodor, Lippert
et al., Science 322 (2008))
• There is room for significant
progress in understanding atomic
nuclei
• Illustration from David Dean
RHIC
JPARC
JLAB
FAIR
RIBF
FRIB
FAIR
GANIL
…
Sherrill EBSS 2015
13
Nuclear Spectroscopy
M. Allmond (ORNL), B. Kay (ANL)
• Incredible variety of excited states in nuclei!
• Regular bands
–
–
I(I+1) behavior: rotational
nℏΩ behavior: vibrational
• Regular bands signatures of nuclear
collectivity (deformed liquid-drop like)
• Bands with no visible patterns are signature
of single-particle effects (shell-effects)
• Where are the effects of the short-range
nature of the nuclear force?
GAMMASPHERE
From W. Nazarewicz, in An Advanced Course in Modern
Nuclear Physics, J.M. Aria, M. Lozano (eds.), Springer (2001)
Sherrill EBSS 2015
14
Our Challenges
• Develop a comprehensive model of atomic nuclei – How do we
understand the structure and stability of atomic nuclei from first
principles?
Why do atoms exist?
• Understand the origin of elements and model extreme
astrophysics environments
Where do atoms come from?
• Use of atomic nuclei to test fundamental symmetries and search
for new particles (e.g. in a search for CP violation)
What are atoms made of?
• Search for new applications of isotopes and solution to societal
problems
What are they good for?
Studies at the extremes of neutron and proton number are necessary
to answer these questions.
Sherrill EBSS 2015
15
The Nuclear Landscape – lectures by
M. Thoennessen (MSU/NSCL)
256 “Stable” – no decay observed
3184 Total in the NNDC Database
Sherrill EBSS 2015
16
World-Wide Rare Isotope Program
How – Lectures by M. Thoennessen, M. Couder (ND)
Sherrill EBSS 2015
17
Major US Project – Facility for Rare
Isotope Beams, FRIB
• Funded by DOE Office
of Science – 2020
completion
• Key Feature is 400kW
beam power (5 x1013
238U ions/s)
• Separation of isotopes
in-flight
– Fast development time
for any isotope
– Suited for all elements
and short half-lives
• Experiments with fast,
stopped and
reaccelerated beams
Sherrill EBSS 2015
18
Prediction of the limits of the nuclear
landscape
J. Erler et al., Nature 486, 509 (2012); AV Afanasjev et al. PLB 726, 680
Total number of 6900(500) possible for atomic numbers less than 120.
Sherrill EBSS 2015
19
There are Predicted Limits to the Number
of Isotopes
 Estimated Possible:
Erler, Birge,
Kortelainen,
Nazarewicz, Olsen,
Stoitsov, Nature 486,
509–512 (28 June
2012) , based on a
study of EDF models
 “Known” defined as
isotopes with at least
one excited state
known (1900 isotopes
from NNDC database)
 Represents what is
possible now
Sherrill EBSS 2015
20
The Number of Isotopes Available for
Study at FRIB
 Estimated Possible:
Erler, Birge,
Kortelainen,
Nazarewicz, Olsen,
Stoitsov, Nature 486,
509–512 (28 June
2012) , based on a
study of EDF models
 “Known” defined as
isotopes with at least
one excited state
known (1900 isotopes
from NNDC database)
 For Z<92 FRIB is
predicted to make >
80% of all possible
isotopes
Sherrill EBSS 2015
21
The value of isotopes
• Definition: An isotope is one of an element’s physical forms.
• July 31, 2015 the price of gold was $1095.46 per ounce
• For 1 cent, you can buy 3000000000000000000 Gold-197
atoms (3x1018 atoms)
• Tritium (radioactive form of hydrogen, Hydrogen-3 or 3H, used
in self illuminating signs) $1.4M per ounce
• Colorless diamond $2M per ounce ( 1 carat = 0.007 ounce)
• Record: Berkelium-249 $280M per ounce
Sherrill EBSS 2015
22
Calcium Isotopes
• Normal Calcium: Calcium-40 $.32 per ounce
20 protons
20 neutrons
• Expensive Calcium: Calcium-48 (.2% natural abundance)
$6M per ounce
20 protons
28 neutrons
Sherrill EBSS 2015
,
Slid
Goal of Current Isotope Research
• Goal: Calcium-60 ( At FRIB we will spend about $10,000 for
1000 atoms)
20 protons
40 neutrons
Sherrill EBSS 2015
24
Comparison of Calculated and Measured
Binding Energies with NN models
• Greens
Function Monte
Carlo
techniques
allow up to
mass number
12 to be
calculated
• Blue 2-body
forces V18
• S. Pieper
B.Wiringa
J Carlson, et al.
NN potential
NN + NNN potential
Sherrill EBSS 2015
,
Slid
Key information from rare isotopes
• Neutron rich
nuclei were key
in determining
the isospin
dependence of
3-body forces
and the
development of
IL-2R from UIX
• New data on
exotic nuclei
continue to lead
to refinements in
the interactions
S. Pieper B.Wiringa, et al.
NN + improved NNN potential
Properties of exotic isotopes are essential in determining NN and NNN potentials
Sherrill EBSS 2015
26
Importance of 3N forces
Nuclear Equation of State – Lectures by S. Yennello (Texas A&M)
Neutron Stars – Lecture by J. Piekarewicz (FSU)
• Key ingredient in
understanding neutron
stars neutron star
masses
• Half-life of 14C (Maris,
Navratil et al. PRL),
structure of calcium
isotopes (Wienholtz et
al. Nature), etc.
S. Gandolfi et al.,
PRC85, 032801 (2012)
Nazarewicz et al.
Sherrill EBSS 2015
27
The Road Map: Understanding the
Stability of Atomic Nuclei - A. Volya
• Step 1: Use ab initio theory(FSU)
and study of exotic rare isotopes
to determine the interactions of nucleons in light nuclei and
connect these to QCD by comparison to lattice calculations of
NN and NNN forces
• Step 2: For mid-mass nuclei use configuration interaction
models. The degrees of freedom and interactions must be
determined from exotic nuclei
• Step 3: Use density functional theory to connect to heavy
nuclei. Exotic nuclei help determine the form and parameters
of the DFT.
The last step is the one that may answer the question of
the limits of nuclei.
Sherrill EBSS 2015
28
Stability of Magic Nuclei
Harder
to
excite
Sherrill EBSS 2015
29
Stability of Magic Nuclei
20 protons
Harder
to
excite
16 protons
14 protons
Sherrill EBSS 2015
,
Slid
Surprise: Changing Magic Numbers
Harder
to
excite
Reason: A tensor force that depends on angular momentum and isospin (Otsuka et al.)
Sherrill EBSS 2015
31
New Physics from Mass Model Comparison
to Data – Lecture M. Redshaw (CMU)
HFB-14: Hartree-Fock-Bogoliubov w/delta pairing
force
S. Goriely, M. Samyn, J.M. Pearson, Phys. Rev. C75
(2007) 064312
J. Duflo, A.P. Zuker, Phys. Rev.
(1995) R23
MEHFB14 C52
– MEAME2003
ME = (Actual
mass
– A u) x 931.5
MeV/u
Shell
Model
Based
u = atomic mass unit (931.5 MeV)
MEDZ – MEAME2003
Less bound than data
More bound than data
www.nuclear masses.org
Sherrill EBSS 2015
32
Weakly bound isotopes have unique
features
• Large neutron skins
• Modified mean field
• Resonance properties
“Normal”
Halo
Tanihata PRL1985
protons Skin
Tanihata PLB1992
neutrons
220Rn
11Li
80Ni
New
Science: Pairing in low-density material, new tests of nuclear models, open
quantum system, interaction with continuum states - Efimov States - Reactions
Sherrill EBSS 2015
33
New insight and physics from extreme halos
and skins
42Mg (Predicted to be produced at 10 atoms/day)
T
Example:
Theory - 100 keV Sn BA Brown
Sherrill EBSS 2015
34
Limits of the Heaviest Nuclides –
Lectures by M. Stoyer (LLNL)
W. Nazarewicz
Sherrill EBSS 2015
35
Half-lives of Superheavy Elements
20
Spherical
Shell
15
10
108
Symbols: exp. values
Lines calc.
Sobiczewski &
Smolanczuk
α - decay
Log Tα (sec.)
1 year
110
5
Deformed
Shell
114
0
118
-5
108
112
-10
116
140
150
170
180
160
Neutron number
190
W. Nazarewicz
Sherrill EBSS 2015
36
One of the Challenges – How many
elements?
Claims for up to Z=118,
but much beyond
requires theory –
application of Density
Functional Theory
- P. Pyykkö: Phys. Chem.
Chem. Phys. 13, 161-168
(2011) “Half of chemistry
is undiscovered.”
- Another view – above
Z=122 all chemistry is the
same due to relativistic
effects
- For stability of Z>120
see also Jachimowicz,
Kowal, Skalski, PRC 83
(2011)
W. Nazarewicz
Sherrill EBSS 2015
37
Some Cool Questions
• Is there a standard model for nuclear structure and what is it?
Are there forces and interactions beyond this nuclear standard
model we will find in nuclei?
• How many elements are possible? What is the extent of the
isotopes of these elements?
• How good is the approximation of neutrons and protons in the
nucleus?
Sherrill EBSS 2015
38
Abundances are inferred from stellar
absorption spectra
• Stellar absorption spectra
recently
formed star
T=4800 K; elements like our sun
Intensity (relative)
Intensity (relative)
• Not all stellar absorption spectra of the same surface temperature are
identical
old star
T=4700 K; only 1/10,000 heavy elements
Sherrill EBSS 2015
39
One of the Challenges – Origin Elemental
Abundances in our Solar System
Lectures by J. Blackmon (LSU)
• Stars are mostly made of
hydrogen and helium, but
each has a unique pattern of
other elements
• The abundance of elements
tell us about the history of
events prior to the formation
of our sun
• The plot at the right shows
the composition in the visible
surface layer of the Sun
(photosphere)
• How were these elements
created prior to the formation
of the Sun?
Asplund, M., Grevesse, N., Sauval,
A.J., Scott, P.: Annu. Rev. Astron.
Astrophys. 47, 481 (2009)


X

dex  12  Log 
 Hydrogen 
Sherrill EBSS 2015
40
Evolution of Elemental Abundances
Plots: M. Weischer NDU
Data from sky surveys and high resolution spectra and meteoritic composition
Sherrill EBSS 2015
41
New data on elemental abundances:
Surveys and Large Aperture Telescopes
• The measurement of elemental abundances
is at the forefront of astronomy using large
telescopes
• Large mirrors enable high resolution
spectroscopic studies in a short time
(Subaru, Hubble, LBT, Keck, …)
• Surveys provide large data sets (SDSS-III,
RAVE, LAMOST, SkyMapper, LSST…)
• Future missions: JWST - “is specifically
designed for discovering and understanding
the formation of the first stars and galaxies,
measuring the geometry of the Universe and
the distribution of dark matter, investigating
the evolution of galaxies and the
production of elements by stars, and the
process of star and planet formation.”
Hubble
Space
SUBARU
Sherrill EBSS 2015
42
Chemical History of the Universe – the
Fossil Evidence of the First Stars
• By measuring the
differences we learn
about the history of
the star
• Barium (Ba) in early
stars must be made
differently from Iron
(Fe)
• See Aoki et al.
SCIENCE 345
(2014) for a recent
discussion
• Complex problem;
nuclear physics is
one part
HERES Survey – Barklem et al. (2005)
Sun [Ba/Fe] = [Fe/H] = 0
 ( Fe abundance/ H abundance) Star 

[Fe/H]  LOG 
 ( Fe abundance/ H abundance) Sun 
Sherrill EBSS 2015
43
Simulation of Solar System Abundances
Timmes, Woosley, Weaver Astro. Journal 1995
Parameters:
• Supernovae type Ia and II
• Number (77 supernovae
with Ms 11-40 Msun)
• Progenitor mass
distributions
• Age of the galaxy
• …
Results:
• SN rate1/3 comes from
type Ia
• They reproduce
measured 7Li abundance
metalicity vs. time etc.
Success ! ? Note above A=72 we can’t model
Sherrill EBSS 2015
44
Nuclear Physics Discoveries Are an
Essential Part of this Revolution
i-process (Cowan & Rose Ap.
J.) nuclear uncertainties lead to
factor of 200 uncertainty in
abundances near N=82 (MG
Bertolli et al., arXiv:1310.4578)
p-process
i-process
s-process
r-process
np-process
Supernova EC process
rp-process
Stellar fusion
Neutron star crust
process
Adapted from Frank Timmes and H Schatz
Sherrill EBSS 2015
45
Tests of Nature’s Fundamental
Symmetries – Lectures P. Mueller (ANL)
• Angular correlations in β-decay
and search for scalar currents
o
o
Mass scale for new particle
comparable with LHC
6He and 18Ne at 1012/s
• Electric Dipole Moments
o
225Ac, 223Rn, 229Pa
(30,000 more
sensitive than 199Hg; I > 1010/s)
• Parity Non-Conservation in atoms
o
weak charge in the nucleus (francium
isotopes; 109/s)
• Unitarity of CKM matrix
o
o
γ
e
212Fr
Z
Vud by super allowed Fermi decay
Probe the validity of nuclear
corrections
Adapted from G Savard
Sherrill EBSS 2015
46
Next Generation Facilities Will Provide
Isotopes Needed for Applications –
Lectures by E. McCutchan (BNL)
• Next generation rare isotope facilities can provide isotopes
for applied science while serving forefront nuclear research
• FRIB is designed to provide fast access to a broad range of
new isotopes for research
“Most of the isotopes in use today in practical
settings were developed as long as 50 years ago.
With few exceptions (e.g., 82Sr and 90Y) there are no
new products or services that use isotopes
developed in the past 20 years. Without the
availability of research isotopes, it is not possible to
develop new science or new applications based on
isotopes. This problem is extreme in the case of
accelerator isotopes …”
Subcommittee Finding
Isotopes for the Nation's Future
NSAC Long Range Plan Study 2008
Sherrill EBSS 2015
47
Targeted Cancer Therapy
• Modern targeted therapies in medicine
take advantage of knowledge of the
biology of cancer and the specific
biomolecules that are important in
causing or maintaining the abnormal
proliferation of cells
• These radionuclides have been relatively
difficult to get in sufficient quantities. The
short-lived alpha emitters are particularly
in demand, especially 225Ac, 213Bi, and
211At.
• Pairs (theragnostic), e.g., 67Cu
(treatment) and 64Cu (dosimetry) are
particularly interesting
• FRIB can parasitically supply demand
for many isotopes
A Long Range Plan , NSACIS 2015
Sherrill EBSS 2015
48
Research Papers Based on 68Ga
Nuclear and
Radiochemistry
Expertise
US National
Academies Press
(2012)
Sherrill EBSS 2015
49
Overview of the 2015 Exotic Beam
Summer School – Dream Team
Speaker
•
•
•
•
•
•
•
•
•
•
•
•
Topic
A. Volya (FSU)
Nuclear Structure (Theory)
M. Thoennessen (MSU/NSCL) Exotic Nuclei (Experiment)
J. Piekarewicz (FSU)
Neutron Stars
S. Yennello (Texas A&M)
Nuclear Reactions (Experiment)
J. Blackmon (LSU)
Nuclear Astrophysics (Experiment)
P. Mueller (ANL)
Fundamental Symmetries
M. Redshaw (CMU)
Precision Nuclear Masses
M. Couder (Notre Dame)
Beam Optics
B. Kay (ANL)
Transfer reaction experiments
J.M. Allmond (ORNL)
Gamma-spectroscopy methods
M. Stoyer (LLNL)
Super-heavy Elements
E. McCutchan (BNL)
Nuclear Data
Sherrill EBSS 2015
50
Summary and Perspective - Our Challenges
• Develop a comprehensive model of atomic nuclei – How do we
understand the structure and stability of atomic nuclei from first
principles?
• Understand the origin of elements and model extreme
astrophysics environments
• Use of atomic nuclei to test fundamental symmetries and search
for new particles (e.g. in a search for CP violation)
• Search for new applications of isotopes and solution to societal
problems
You have a good chance to be the people who meet these challenges.
Sherrill EBSS 2015
51
Backup Slides
Sherrill EBSS 2015
52
Overlap of Nucleons and Their Potential
N. Ishii, S. Aoki, T. Hatsuda, Phys.
Rev. Lett. 99, 022001 (2007)
• What is the nature of the “hard-core” repulsion in the nuclear force?
• Where does the nature of this repulsion show up in nuclear structure?
Sherrill EBSS 2015
53
However…Are Nucleons Modified in the
Nuclear Medium? Maybe Yes
• EMC “European Muon Collaboration” Effect circa 1983, CERN
• J.Seely, et al, "New Measurements of the EMC Effect in Very Light Nuclei“
PRL 103 (2009) 202301
Sherrill EBSS 2015
54
Short Range Correlations Show a
Preference for NP vs PP Pairs
This is understood as a result of the tensor part of the nuclear force.
Sherrill EBSS 2015
55
Observation: EMC Effect is Correlated
with SRC
• N. Formin et al. , PRL 108 (2012) 092502
Sherrill EBSS 2015
56
A Voyage of Discovery
 FRIB has a
chance to make
something like
4500 isotopes, or
80% of all the
ones possible for
Z<92.
 This process will
be a voyage of
discovery!
Sherrill EBSS 2015
57