why crex after prex? witold nazarewicz (utk/ornl) calcium radius experiment (crex) workshop at...
TRANSCRIPT
Why CREX After PREX?
Witold Nazarewicz (UTK/ORNL)
Calcium Radius Experiment (CREX) Workshop at Jefferson Lab, Mar. 17-19, 2013
Main contributors:
Jochen Erler
Chuck Horowitz
Jorge Piekarewicz
Paul-Gerhard Reinhard
+ Milano, Zagreb, Kolkata groups
+UNEDF/NUCLEI
OUTLINE
• General principles
o Theoretical strategies
• Ab initio theory and 3N forces
o T=1/2 and T=3/2 channels
• Leptodermous expansion
o Is 48Ca as good “piece of nuclear matter” as 208Pb?
• Density Functional Theory expectations
• Neutron star relevance
o Yes, there is some, but…
• Systematic trends
o … and uncertainties
• Bottom line: why CREX
48Ca
208Pb
n
Physics of nuclei is demanding
Input
Forces, operators
• rooted in QCD
• insights from Density Functional Theory
• many-body interactions
• in-medium renormalization
• low-energy coupling constants optimized to data
• crucial insights from exotic nuclei
Many-body
dynamics
• many-body techniques
o direct ab-initio schemes
o symmetry-based truncations
o symmetry breaking and restoration
• high-performance computing
Open
channels
nuclear structure impacted by couplings to
reaction and decay channels
Interfaces provide
crucial clues
dimension of the problem
H.-W. Hammer, A. Nogga, A. Schwenk
Three-body forces: From cold atoms to nuclei, Rev. Mod. Phys. 85, 197 (2013)
A.T. Gallant et al.,
Phys. Rev. Lett. 109, 032506 (2012)
Three-body forces and shell structure in calcium isotopes
J.D. Holt et al.,
J.Phys.G 39, 085111 (2012)
Ab-initio description of Calcium isotopes
G. Hagen et al., Phys. Rev. Lett. 109, 032502 (2012)
RIKEN
500 MeV N3LO NN potential combined with N2LO 3NF
Neutron matter based on SRG-evolved chiral three-nucleon
interactions
K. Hebeler and R. J. Furnstahl
Phys. Rev. C 87, 031302(R) (2013)
Neutron matter EOS including NN, 3N and 4N cEFT forces at
N3LO
I. Tews et al.
Phys. Rev. Lett. 110, 032504 (2013)
The counting of triples seems to work only in very light nuclei…Local density estimates based on
infinite matter suggest a ratio of three-body to two-body scaling proportional to the first power of
the density.
From Finite Nuclei to the Nuclear Liquid Drop
Leptodermous Expansion Based on the Self-consistent Theory
P.G. Reinhard et al., Phys. Rev. C 73, 014309 (2006)
The limitations of applying the leptodermous expansion for finite nuclei are discussed. While the leading terms in the macroscopic energy expansion can be extracted very
precisely, the higher-order, isospin-dependent terms are prone to large uncertainties due to finite-size effects.
We expand the smooth energy in terms of 1/R and I2…
Liquid-Drop Expansion
O(0) O(1) O(2)
asurf
300 12510008000
Conclusion: Properties of 48Ca are dramatically affected by surface effects
Quantities of interest…
bulk equilibrium
symmetry energy
symmetry energy
at surface density
slope of binding energy
of neutron matter
dipole polarizability
neutron skin
Information content of a new observable
P.G. Reinhard and WN, Phys. Rev. C 81, 051303 (R) (2010)
Good isovector
indicators
Poor isovector
indicators
more in talk by Jorge Piekarewicz
F.J.Fattoyev et al., Phys.Rev. C 86, 025804 (2012)
M. Kortelainen et al.,
Phys. Rev. C 82, 024313 (2010)
Phys.Rev. C 85, 024304 (2012)
Early attempts to employ statistical methods of linear-regression and error analysis have been revived recently and been applied to determine the correlations
between model parameters, parameter uncertainties, and the errors of calculated observables. This is essential for providing predictive capability and extrapolability,
and estimate the theoretical uncertainties.
M. Kortelainen et al., Phys. Rev. C 77, 064307 (2008)
J. Toivanen et al., Phys. Rev. C 78, 034306 (2008)
P. Klüpfel et al., Phys. Rev. C 79, 034310 (2009)
U. Lombardo, Prog.Theor.Phys.(Kyoto), Suppl. 196, 39 (2012)
Lots of action on a DFT front
Erler et al. Nature 486, 509 (2012)
• Surface (shell) effects very large in 48Ca
• Isovector properties not fully controlled
• Important insights from ab-initio theory
Gandolfi et al. PRC85, 032801 (2012)
Erler et al., arXiv:1211.6292 (2012)
PREX:
Tamii et al.:
Theory:
E1 polarizability provides excellent constaint
J. Piekarewicz et al., Phys. Rev. C 85, 041302(R) (2012)
J. Piekarewicz et al.,
Phys. Rev. C 85, 041302(R) (2012).
P.G. Reinhard et al.,
in preparation (2013)
P.G. Reinhard et al., in preparation (2013)
the large span of predictions for 48Ca
rskin
=(0.168 ± 0.022) fm in 208Pb
J. Piekarewicz et al.,
Phys. Rev. C 85, 041302(R) (2012)
rskin
=(0.168 ± 0.022) fm in 208Pb
rskin
=(0.176 ± 0.018) fm in 48Ca
Mammei (Sunday):
Drskin
= ± 0.06 fm in 208Pb
Drskin
= ± 0.03 fm in 48Ca
Projected uncertainties
2013
Summary: Why CREX after PREX?
• Precise PREX-II data needed to clarify the situation after PREX. (If the mean value of PREX for neutron skin is
correct, there is something basically wrong with our current models of nuclei).
• The isovector data for 48Ca offer stronger model dependence than the corresponding 208Pb data; hence,
they provide tighter constraints.
• 48Ca can be computed with ab-initio approaches and with DFT.
• 48Ca data can provide a test of 3N forces (T=3/2 and T=1/2), which are important for the neutron matter EOS;
hence, neutron star physics.
• The combination of precise data on dipole polarizability and neutron skin will provide stringent constraints on
nuclear structure models.
• 48Ca is affected by surface/shell effects more dramatically than 208Pb. Therefore, the main motivation is in nuclear structure.
Astrophysical motivation is secondary, mainly related to 3N forces and/or gradient terms.
• Lots of activities worldwide on optimization/quantification of nuclear models.