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Neutron Skins and Neutron Stars Physics with Intense Polarized Electron Beams Organizing Committee Chuck Horowitz (Indiana) Kees de Jager (JLAB) Jim Lattimer (Stony Brook) Witold Nazarewicz (UTK, ORNL) Jorge Piekarewicz (FSU Sponsors: Jefferson Lab, JSA PREXis a fascinating experiment that uses parity violation to accurately determine the neutron radius in Pb. This has broad applications to astrophysics, nuclear structure, atomic parity non- conservation and tests of the standard model. The conference will begin with introductory lectures and we encourage new comers to attend. For more information contact [email protected] Topics Parity Violation Theoretical descriptions of neutron-rich nuclei and bulk matter Laboratory measurements of neutron-rich nuclei and bulk matter Neutron-rich matter in Compact Stars / Astrophysics Website: http://conferences.jlab.org/PREX MIT - March 14-16, 2013 J. Piekarewicz (FSU) Neutron Skins and Neutron Stars MIT - March 14-16, 2013 1 / 13

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Page 1: Neutron Skins and Neutron Starsweb.mit.edu/lns/PEB_Workshop/talks/JPiekarewicz.pdfNeutron-Star Structure Neutron Stars satisfy the Tolman-Oppenheimer-Volkoff equation General-Relativistic

Neutron Skins and Neutron Stars

Physics with Intense Polarized Electron Beams

Organizing Committee

Chuck Horowitz (Indiana)

Kees de Jager (JLAB)

Jim Lattimer (Stony Brook)

Witold Nazarewicz (UTK, ORNL)

Jorge Piekarewicz (FSU

Sponsors: Jefferson Lab, JSA

PREX is a fascinating experiment that uses parity

violation to accurately determine the neutron

radius in 208Pb. This has broad applications to

astrophysics, nuclear structure, atomic parity non-

conservation and tests of the standard model. The

conference will begin with introductory lectures

and we encourage new comers to attend.

For more information contact [email protected]

Topics

Parity Violation

Theoretical descriptions of neutron-rich nuclei and

bulk matter

Laboratory measurements of neutron-rich nuclei

and bulk matter

Neutron-rich matter in Compact Stars / Astrophysics

Website: http://conferences.jlab.org/PREX

MIT - March 14-16, 2013

J. Piekarewicz (FSU) Neutron Skins and Neutron Stars MIT - March 14-16, 2013 1 / 13

Page 2: Neutron Skins and Neutron Starsweb.mit.edu/lns/PEB_Workshop/talks/JPiekarewicz.pdfNeutron-Star Structure Neutron Stars satisfy the Tolman-Oppenheimer-Volkoff equation General-Relativistic

My FSU Collaborators

Genaro Toledo-SanchezKarim HasnaouiBonnie Todd-RutelBrad FutchJutri TarunaFarrukh FattoyevWei-Chia Chen

My Outside Collaborators

B. Agrawal (Saha Inst.)M. Centelles (U. Barcelona)G. Colò (U. Milano)C.J. Horowitz (Indiana U.)W. Nazarewicz (U. Tennessee)N. Paar (U. Zagreb)M.A. Pérez-Garcia (U.Salamanca)P.G.- Reinhard (U.Erlangen-Nürnberg)X. Roca-Maza (U. Milano)D. Vretenar (U. Zagreb)

J. Piekarewicz (FSU) Neutron Skins and Neutron Stars MIT - March 14-16, 2013 2 / 13

Page 3: Neutron Skins and Neutron Starsweb.mit.edu/lns/PEB_Workshop/talks/JPiekarewicz.pdfNeutron-Star Structure Neutron Stars satisfy the Tolman-Oppenheimer-Volkoff equation General-Relativistic

Neutron Skins and Density Dependence of the Symmetry Energy

Neutron densities are as fundamental as proton (charge) densitiesYet, still elusive after more than 80 years of nuclear physics

Hinders our understanding of density dependence symmetry energyPenalty for breaking N=Z symmetry [B(Z ,N) = −aa(N−Z )2/A + . . .]

Neutron matter as a resonant Fermi Gas with large effective rangeUniversality of dilute Fermi gases with infinite scattering length

Neutron skin strongly correlated to the symmetry pressure L∝PPNMSlope (pressure) of pure neutron matter poorly constrained

Symmetry (or PNM) pressure pushes against surface tension⇒ n-skin

0.2 0.4 0.6 0.8 1.0 1.2kF (fm-1)

0

2

4

6

8

E/N

(MeV

)

Schwenk-PethickFriedman-PandharipandeHF-Vlow-k (S-P)Hebeler-SchwenkGandolfi et al.Gezerlis-CarlsonVidana et al.NL3FSUIU-FSU

Pure Neutron Matter

Ferm

i Gas

J. Piekarewicz (FSU) Neutron Skins and Neutron Stars MIT - March 14-16, 2013 3 / 13

Page 4: Neutron Skins and Neutron Starsweb.mit.edu/lns/PEB_Workshop/talks/JPiekarewicz.pdfNeutron-Star Structure Neutron Stars satisfy the Tolman-Oppenheimer-Volkoff equation General-Relativistic

Neutron-Star StructureNeutron Stars satisfy the Tolman-Oppenheimer-Volkoff equationGeneral-Relativistic extension of Newtonian gravity (vesc/c . 1/2)Only unknown physics is the Equation of State [P = P(E)]EOS must span 10-11 orders of magnitude in baryon densityEnormous uncertainty in the prediction of neutron-star radiiPREX places a significant constraint on neutron-star radii

dMdr

= 4πr2E(r)

dPdr

= −GE(r)M(r)

r2

[1 +

P(r)E(r)

][1 +

4πr3P(r)M(r)

] [1− 2GM(r)

r

]−1

Need an E vs P relation!

J. Piekarewicz (FSU) Neutron Skins and Neutron Stars MIT - March 14-16, 2013 4 / 13

Page 5: Neutron Skins and Neutron Starsweb.mit.edu/lns/PEB_Workshop/talks/JPiekarewicz.pdfNeutron-Star Structure Neutron Stars satisfy the Tolman-Oppenheimer-Volkoff equation General-Relativistic

Enhanced Cooling as signature for Quark Stars: the case of 3C58

Core-collapse supernovae generates hot (proto) neutron star T '1012KNeutron stars cool promptly by ν-emission (D-URCA process)Standard (“inefficient") cooling scenario takes over (M-URCA process)Thermal emissions from 3C58 far below standard cooling scenario

This requires the presence of exotic stellar cores!Neutrino “enhanced” cooling driven by exotic matter (π, K , q . . .)

Unless symm. energy is stiff: large neutron skin⇔ large Yp ⇔ DURCA

J. Piekarewicz (FSU) Neutron Skins and Neutron Stars MIT - March 14-16, 2013 5 / 13

Page 6: Neutron Skins and Neutron Starsweb.mit.edu/lns/PEB_Workshop/talks/JPiekarewicz.pdfNeutron-Star Structure Neutron Stars satisfy the Tolman-Oppenheimer-Volkoff equation General-Relativistic

The Stellar Crust: Nuclear Crystals and Nuclear PastaFRIB ... will provide an understanding of matter in the crust of neutron stars (2007 Long Range Plan)

At crustal densities uniform state unstable against cluster formationCoulomb Crystal of neutron-rich nuclei immersed in a uniform e− gas56Fe, 62Ni, 68Ni, . . ., 118

36 Kr82(?)Coulomb frustration drives the formation of complex topological shapes“Nuclear Pasta” or “Micro-emulsions in 2D e-gas"Neutron-rich nuclei highly sensitive to symmetry energyNuclear Pasta highly sensitive to proton fractionSmall neutron skin⇔ large proton fraction⇔ Nuclear Pasta

J. Piekarewicz (FSU) Neutron Skins and Neutron Stars MIT - March 14-16, 2013 6 / 13

Page 7: Neutron Skins and Neutron Starsweb.mit.edu/lns/PEB_Workshop/talks/JPiekarewicz.pdfNeutron-Star Structure Neutron Stars satisfy the Tolman-Oppenheimer-Volkoff equation General-Relativistic

Neutron Stars and Density Dependence of the Symmetry Energy

Stellar radius strongly correlated to the symmetry pressure L∝PPNM

Symmetry (or PNM) pressure pushes against gravity⇒ NS radius

Symmetry (or PNM) pressure correlated to a myriad of NS observablesNS-radii, proton fraction, core-crust transition density, DUrca cooling, ...

40 50 60 70 80L (MeV)

12

12.5

13

13.5

14

14.5

R NS [

M/M

sun]

(km

) RNS[0.8]RNS[1.4]

CAB=0.988

FSUGold

CAB=0.946

0 0.2 0.4 0.6 0.8 1Correlation with L

t

skin 132Sn

RNS[1.4]

skin 48Ca

RNS[0.8]

skin 208Pb

L

MDUrca

PPNM

Yp

J. Piekarewicz (FSU) Neutron Skins and Neutron Stars MIT - March 14-16, 2013 7 / 13

Page 8: Neutron Skins and Neutron Starsweb.mit.edu/lns/PEB_Workshop/talks/JPiekarewicz.pdfNeutron-Star Structure Neutron Stars satisfy the Tolman-Oppenheimer-Volkoff equation General-Relativistic

Heaven on Earth: Neutron Skins and Neutron Stars

Same dynamical origin to neutron skin and NS radiusSame pressure creates neutron skin and NS radius

Correlation among observables differing by 18 orders of magnitude!

NS radius sensitive to the high-density component of the EOSHence the model dependence ...

Large neutron skin and small neutron radius?May be evidence in favor of a phase transition to exotic matter

The larger the neutron skin, the larger the neutron-star radius ...

0.16 0.20 0.24 0.28rskin[208Pb] (fm)

12

12.5

13

13.5

14

R[1.4

] (km

)

phase transition?

FSUGold

NL3

J. Piekarewicz (FSU) Neutron Skins and Neutron Stars MIT - March 14-16, 2013 8 / 13

Page 9: Neutron Skins and Neutron Starsweb.mit.edu/lns/PEB_Workshop/talks/JPiekarewicz.pdfNeutron-Star Structure Neutron Stars satisfy the Tolman-Oppenheimer-Volkoff equation General-Relativistic

PREX: The Lead Radius EXperiment [PRL 108, 112502 (2012)]

Ran for 2 months on April-June 2010 Organizing Committee

Chuck Horowitz (Indiana)

Kees de Jager (JLAB)

Jim Lattimer (Stony Brook)

Witold Nazarewicz (UTK, ORNL)

Jorge Piekarewicz (FSU

Sponsors: Jefferson Lab, JSA

PREX is a fascinating experiment that uses parity

violation to accurately determine the neutron

radius in 208Pb. This has broad applications to

astrophysics, nuclear structure, atomic parity non-

conservation and tests of the standard model. The

conference will begin with introductory lectures

and we encourage new comers to attend.

For more information contact [email protected]

Topics

Parity Violation

Theoretical descriptions of neutron-rich nuclei and

bulk matter

Laboratory measurements of neutron-rich nuclei

and bulk matter

Neutron-rich matter in Compact Stars / Astrophysics

Website: http://conferences.jlab.org/PREX

First purely electroweak (clean!) measurement of Rn(208Pb)

Promised a 1% measurement of Rn(208Pb)

Uses parity violation as Z0 couples preferentially to neutrons[Donnelly, Dubach, Sick, NPA 503, 589 (1989)]

up-quark down-quark proton neutronγ-coupling +2/3 −1/3 +1 0Z0-coupling ≈ +1/3 ≈ −2/3 ≈ 0 −1

gv=2tz − 4Q sin2 θW≈2tz−Q

A Physics case for PREX-II and beyond!J. Piekarewicz (FSU) Neutron Skins and Neutron Stars MIT - March 14-16, 2013 9 / 13

Page 10: Neutron Skins and Neutron Starsweb.mit.edu/lns/PEB_Workshop/talks/JPiekarewicz.pdfNeutron-Star Structure Neutron Stars satisfy the Tolman-Oppenheimer-Volkoff equation General-Relativistic

The Case for PREX-II, Super-PREX, CREX, and beyond

R208skin correlated to a myriad of NS observables (radii, cooling, glitches ...)

How accurate measure R208skin to constrain L to within a given error?

Many observables with realistic ± to constrain L to within a given error?R208

skin ,R48skin, α

208D , . . .

0 0.2 0.4 0.6 0.8 1Correlation with skin of 208Pb

skin 132Sn

RNS[0.8]RNS[1.4]

skin 48Ca

lt

skin 208Pb

L

Ypt

MDUrca

Icrust[0.8]

Stru

ctur

ePa

sta

Cooling

Glitches

40 50 60 70 80L (MeV)

0.18

0.2

0.22

0.24

R ski

n[20

8 Pb] (

fm) 6L/2

lAB=0.995

6Lmin=1.18 MeV

0.01

5 fm

J. Piekarewicz (FSU) Neutron Skins and Neutron Stars MIT - March 14-16, 2013 10 / 13

Page 11: Neutron Skins and Neutron Starsweb.mit.edu/lns/PEB_Workshop/talks/JPiekarewicz.pdfNeutron-Star Structure Neutron Stars satisfy the Tolman-Oppenheimer-Volkoff equation General-Relativistic

Systematic Theoretical Errors: Comparison among EDFs

Correlation between E1 polarizability and R208skin remains robust (0.77)

Piekarewicz et al., PRC 85, 041302(R) (2012)

... the impact of a 1% measurement of R208n is much smaller on the EOS

Reinhard-Nazarewicz, PRC 81, 051303(R) (2010)

... although very demanding, an accuracy of 0.02 fm in R208skin is desired

Roca-Maza et al., PRL 106, 252501 (2011)

... in order to constrain theory an accuracy of .0.03 fm is requiredPiekarewicz et al., PRC 85, 041302(R) (2012)

We suggest a 0.5% Super-PREX measurement to constrain the EOSFattoyev-Piekarewicz, PRC 86, 015802 (2012)

v090MSk7

HFB-8SkP

HFB-17SkM

*DD-M

E2DD-M

E1FSUGoldDD-PC1Ska

PK1.s24Sk-Rs

NL3.s25Sk-T4G2

NL-SV2PK1NL3

NL3*NL2

NL1

0 50 100 150 L(MeV)

0.1

0.15

0.2

0.25

0.3

0.35r sk

in[20

8 Pb](

fm)

Linear Fit, r = 0.979Mean Field

D1S

D1NSGII

Sk-T6SkX SLy5

SLy4

MSkA

MSL0

SIVSkSM

*SkM

P

SkI2SV

G1

TM1

NL-SHNL-RA1

PC-F1

BCP

RHF-PKO3Sk-GsRHF-PKA1

PC-PK1

SkI5

PREX-II

S-PREX

(63±16)Roca-Maza et al.

PRL106,252501(2011)

0.12 0.16 0.2 0.24 0.28 0.32rskin[208Pb](fm)

18

19

20

21

22

23

24

25

26

_D[20

8 Pb](f

m3 )

PREX-IIS-PREX

NL3/FSUDD-MESkyrmeSkyrme (SV)

RCNP

CABmodels =0.769

Few observables with realistic uncertainty to constrain the EOSJ. Piekarewicz (FSU) Neutron Skins and Neutron Stars MIT - March 14-16, 2013 11 / 13

Page 12: Neutron Skins and Neutron Starsweb.mit.edu/lns/PEB_Workshop/talks/JPiekarewicz.pdfNeutron-Star Structure Neutron Stars satisfy the Tolman-Oppenheimer-Volkoff equation General-Relativistic

PREX-II, Super-PREX, CREX as Anchors for FRIB Physics“One of the main science drivers of FRIB is the study of nuclei with neutron skins 3-4 times thicker than is currently possible.FRIB will provide rare isotopes to explore the properties of halos and skins. JLab uses parity violation to measure the neutronradius of stable lead and calcium nuclei. Studies of neutron skins at JLab and FRIB will help pin down the behavior of nuclearmatter at densities below twice typical nuclear density” 2013 Subcommittee Report to NSAC

The Traditional Approach: Proton-Nucleus ScatteringFRIB will scatter protons from radioactive nuclei in inverse kinematicsLarge and uncontrolled uncertainties in the reaction mechanismEnormous ambiguities yield an energy dependent neutron skinFRIB must use PREX-II and CREX as calibrating anchors

J. Piekarewicz (FSU) Neutron Skins and Neutron Stars MIT - March 14-16, 2013 12 / 13

Page 13: Neutron Skins and Neutron Starsweb.mit.edu/lns/PEB_Workshop/talks/JPiekarewicz.pdfNeutron-Star Structure Neutron Stars satisfy the Tolman-Oppenheimer-Volkoff equation General-Relativistic

Conclusions and OutlookSole ingredient required to understand neutrons stars is theEOS of neutron-rich matter in beta-equilibriumNeutron skins play a critical role in elucidating the richstructure, composition, and dynamics of neutron starsCovariance analyses uncover correlations and dictate therequired accuracy of laboratory experimentsElectroweak measurements of neutron skins should serveas anchors for hadronic experiments at FRIB-type facilitiesThe combination of precise data on dipole polarizabilityand neutron skins will provide stringent constraints onnuclear structure modelsAccurate measurements of neutron radii will continue toplay a fundamental role in elucidating the physics ofneutron-rich systems in both heaven and earth!

J. Piekarewicz (FSU) Neutron Skins and Neutron Stars MIT - March 14-16, 2013 13 / 13