Symmetry Energy Project (SEP)

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1 Symmetry Energy Project (SEP) Determination of the Equation of State of Asymmetric Nuclear Matter NSCL MSU, USA: B. Tsang & W. Lynch, RIKEN, JP: Hiroshi Sakurai, Shunji E. Brown, Zibi Chajecki, Pawel Danielewicz, Nishimura, Yoichi Nakai, Atsushi Taketani A. Steiner, Gary Westfall. Kyoto University: Tetsuya Murakami Texas A&M University, College Station: Tohoku University: Akira Ono Sherry Yennello, A. McIntosh Rikkyo University: Jiro Murata, K. Ieki Western Michigan University: Michael Famiano GSI,DE: Wolfgang Trautmann, Yvonne Leifels Daresbury Laboratory, UK: Roy Lemmon INFN LNS, Catania, IT: Giuseppe Verde, Angelo Pagano, Paulo Russotto, Massimo di Toro, Maria Colonna, Aldo Bonasera, Vincenzo Greco SUBATECH, FR: Christoph Hartnack GANIL, FR: Abdou Chbihi, John Frankland, Jean-Pierre Wieleczko China Institute of Atomic Energy: Yingxun Zhang, Zhuxia Li, Fei Lu (Peking University), Y.G. Ma, Wendong Tian (Chinese Shanghai Academy of Sciences) Brazil: Sergio Souza, Raul Donangelo, Brett Carlson

2 Symmetry Energy Project (SEP) Outline I. Introduction of NSCL, FRIB, rare isotopes II. Equation of State of Symmetric Nuclear Matter III. Symmetry energy in EoS of Asymmetric Matter A. Constraints from HIC a) n/p ratios b) Isospin diffusion B. Constraints from other observables from finite nuclei a) Nuclear masses Isobaric Analog States b) Neutron skin thicknesses c) Pygmy Dipole Resonances d) Giant Dipole Resonances e) Current Status of the Symmetry Energy Project IV. Current Status of the Symmetry Energy Project V. Summary & Conclusion

The National Superconducting Cyclotron Laboratory @Michigan State University A

astro-nuclear physics, accelerator physics, and societal applications 431

3 The National Superconducting Cyclotron State University A national user facility for rare isotope research and education in nuclear science, astro-nuclear physics, accelerator physics, and societal applications 431 employees, including 35 faculty, 70 graduate and 59 undergraduate students as of December 7, 2010

4 NSCL Michigan State University

FRIB will enable scientists to make discoveries about the properties of these rare isotopes in order to

5 Facility for Rare Isotope Beams (FRIB) FRIB will provide intense beams of rare isotopes (that is, short-lived nuclei not normally found on Earth). FRIB will enable scientists to make discoveries about the properties of these rare isotopes in order to better understand the physics of nuclei, nuclear astrophysics, fundamental interactions, and applications for society. Cost: $640M; construction start: 2013; completion: 2020

6 Proton Number Z From Elements to Rare isotopes Neutron Number N

Equation of State (EoS) Ideal gas: PV=nRT 30 EOS for Asymmetric Matter E/A (MeV) 20 10 0 Soft (=0, K=200 MeV)

7 Equation of State (EoS) Ideal gas: PV=nRT 30 EOS for Asymmetric Matter E/A (MeV) Soft (=0, K=200 MeV) asy-soft, =1/3 (Colonna) asy-stiff, =1/3 (PAL) =( - )/( + ) n p n p (fm -3 )

8 Measure collisions Procedure to study EOS Simulate collisions with transport theory (IBUU04, Li et al) Identify observables that are sensitive to EOS Directed transverse flow (in-plane) Elliptical flow out of plane, e.g. squeeze-out Find the mean field(s) that describes the data. Constrain the relevant input variables in the transport models by additional data. Use the mean field potentials to calculate the EOS.

9 Constraining the EOS using Heavy Ion collisions Au+Au collisions E/A = 1 GeV) pressure contours density contours Two observable due to the high pressures formed in the overlap region: Nucleons deflected sideways in the reaction plane. Nucleons are squeezed out above and below the reaction plane..

10 Determination of symmetric matter EOS from nucleus-nucleus collisions in plane / p x y A out of plane The curves represent calculations with parameterized Skyrme mean fields They are adjusted to find the pressure that replicates the observed flow. P (MeV/fm 3 ) 100 Danielewicz et al., Science 298,1592 (2002). symmetric matter RMF:NL3 10 Fermi gas Boguta Akmal K=210 MeV K=300 MeV experiment O / 0 The boundaries represent the range of pressures obtained for the mean fields that reproduce the data. They also reflect the uncertainties from the input parameters in the model.

11 Nuclear Equation of State E/A (,) = E/A (,0) + 2 S() = ( n - p )/ ( n + p ) = (N-Z)/A E sym S o L B K sym 18 B E L 30 sym B B 0 3 P 0 sym Research with rare isotope beams Nuclear Structure What is the nature of the nuclear force that binds protons and neutrons into stable nuclei and rare isotopes? Nuclear Astrophysics What is the nature of neutron stars and dense nuclear matter? What is the origin of elements heavier than iron in the cosmos? What are the nuclear reactions that drive stars and stellar explosions? Tests of Fundamental Symmetries Why is there now more matter than antimatter in the universe?

12 Symmetry Energy Project (SEP) Determination of the Equation of State of Asymmetric Nuclear Matter NSCL MSU, USA: B. Tsang & W. Lynch, RIKEN, JP: Hiroshi Sakurai, Shunji E. Brown, Zibi Chajecki, Pawel Danielewicz, Nishimura, Yoichi Nakai, Atsushi Taketani A. Steiner, Gary Westfall. Kyoto University: Tetsuya Murakami Texas A&M University, College Station: Tohoku University: Akira Ono Sherry Yennello, A. McIntosh Rikkyo University: Jiro Murata, K. Ieki Western Michigan University: Michael Famiano GSI,DE: Wolfgang Trautmann, Yvonne Leifels Daresbury Laboratory, UK: Roy Lemmon INFN LNS, Catania, IT: Giuseppe Verde, Angelo Pagano, Paulo Russotto, Massimo di Toro, Maria Colonna, Aldo Bonasera, Vincenzo Greco SUBATECH, FR: Christoph Hartnack GANIL, FR: Abdou Chbihi, John Frankland, Jean-Pierre Wieleczko China Institute of Atomic Energy: Yingxun Zhang, Zhuxia Li, Fei Lu (Peking University), Y.G. Ma, Wendong Tian (Chinese Shanghai Academy of Sciences) Brazil: Sergio Souza, Raul Donangelo, Brett Carlson

13 Hubble ST Proton Number Z B a Aa A Symmetry Energy in Nuclei Z( Z 1) a C A 2/3 V S 1/ 3 ( A 2Z) A a sym 2 ( a V sym A a S sym A 2 2 / 3 ( A 2Z) ) 2 A Inclusion of surface terms in symmetry Crab Pulsar Neutron Number N

14 Symmetry energy on vastly differing length scales ~10-15 m ~10 4 m 208 Pb Neutron Star extrapolation from 208 Pb radius to n-star radius C.J. Horowitz, J. Piekarewicz, Phys. Rev. Lett. 86 (2001) 5647

15 Extrapolation from 208 Pb radius to n-star radius

16 Relationship to EoS Nuclear masses and the EoS M c Zm c A Z m c B 2 E / A (,0, ) (,0,0) S ; n p / a sym (volume) =S( o ) a sym (surface) S() at sub-saturation densities 1/2 o. Fits of the binding energy formula to experimental masses to provide values for a v, a s, a c, a sym and using AME2003, NPA 729, (2003) 129, 337. The best fits may not give reasonable parameters: Problems: The binding energy formula is not unique a sym A B a Problems: a sym is small compared to other terms. a c, a sym are strongly correlated & shell effects are large. Can we isolate a sym from the rest of formula? A,Z p n A,Z Aa A 2/3 V S 1/ N Z 2 / 3 N Z A 2 OR avb1 asb2a 2 OR A A 1 Z( Z 1) a C A ( A 2Z) A a sym 2 A (Danielewicz, NPA727 (2003) 233) 1/ 3 N Z A 2 2

17 Symmetry coefficient from Isobaric Analog States E a V A a S A /3 Z ( N Z) ac a 1/3 a A A E mic Charge invariance: invariance of nuclear interactions under rotations in n-p space P. Danielewicz & J. Lee, NPA 818, 36 (2009)

18 Measurements of radii Karataglidis et al., PRC (2002) 208 Pb(p,p) E p =200 MeV <r n2 > 1/2 =5.7 fm <r n2 > 1/2 =5.6 fm Proton elastic scattering is sensitive to the neutron density, but the results can be ambiguous. Parity violating electron scattering may provide strong constraints on <r n2 > 1/2 - <r p2 > 1/2 and on S() for < s. Expected uncertainties are of order 0.06 fm. (Horowitz et al., Phys. Rev. 63, (2001).) cm (deg) O

19 Symmetry Energy from Nuclear collective motion Pygmy Dipole Resonance Giant Dipole Resonance Collective oscillation of neutron skin against the Core n-skin thickness Collective oscillation of neutrons against protons From Angela Bracco

20 Density dependence of Symmetry Energy How to reach different nuclear matter density?

21 Bulk nuclear matter properties from Heavy Ion Central Collisions E/A=1600 MeV 200 MeV 50 MeV Highest density reached by central collisions depends on incident beam energy. Pions, n, p fragments Types of fragment formed depend on emission times and density.

22 Heavy Ion collision: 124 Sn+ 124 Sn, E/A=50 MeV Reaction mechanism of fragment productions depends on impact parameters b=0 fm multifragmentation Charged fragments (Z=3-20) are formed at subnormal density b=7 fm Neck fragments S()=12.5(/ o ) 2/3 +19(/ o ) g i

projectile and targets 124 Sn+ 124 Sn, 124 Sn+ 112 Sn, 112 Sn+ 124 Sn, 112 Sn+ 112 Sn Measure N/Z compositions of emitted

23 Hubble ST Proton Number Z Strategies used to study the symmetry energy with Heavy Ion collisions Isospin degree of freedom B a Aa A Z( Z 1) a C 2/3 V S 1/ 3 2 A ( A 2Z) a sym A Neutron Number N Crab Pulsar Vary the N/Z compositions of projectile and targets 124 Sn+ 124 Sn, 124 Sn+ 112 Sn, 112 Sn+ 124 Sn, 112 Sn+ 112 Sn Measure N/Z compositions of emitted particles n & p yields isotopes yields isospin diffusion Results interpreted with transport models that simulate the collisions.

Two observation n/p ratios and isispin diffusion E/A (,) = E/A (,0) + 2 S() = ( n - p )/ ( n + p ) = (N-Z)/A V asy (MeV) 100 50 0 stiff Li et al.

24 Two observation n/p ratios and isispin diffusion E/A (,) = E/A (,0) + 2 S() = ( n - p )/ ( n + p ) = (N-Z)/A V asy (MeV) stiff Li et al., PRL 78 (1997) 1644 soft Neutron Proton Vary N/Z of projectile & target Projectile 124 Sn u = / o Y(n)/Y(p); t/ 3 He, p + /p - Target 112 Sn Isospin Diffusion; low, E beam

25 Famiano et al n/p Experiment 124 Sn+ 124 Sn; 112 Sn+ 112 Sn; E/A=50 MeV Scattering Chamber

26 Isotope Distribution Experiment MSU, IUCF, WU collaboration Sn+Sn collisions involving 124 Sn, 112 Sn at E/A=50 MeV Miniball + Miniwall 4 p multiplicity array Z identification, A<4 LASSA Si strip +CsI array Good E, position, isotope resolutions Xu et al, PRL, 85, 716 (2000)

27 Use of transport model to describe np ratios and two isospin diffusion measurements 0.4g i g i g i 0.95 Consistent constraints from the 2 analysis S()=12.5(/ o ) 2/3 +C (/ o ) g i C17.6; 0.4g i 1 E sym S o L 3 B 0 K 0 sym B

28 Constraints on symmetry energy at subnormal density from existing data GDR: Trippa, PRC77, Tsang et al., PRL 102, (2009) S()=12.5(/ o ) 2/ (/ o ) g IAS : Danielewicz, Lee, NPA 818, 36 (2009) PDR: A. Klimkiewicz, PRC 76, (2007) A.Carbone, O.Wieland PRC81,041301(2010) Tsang et al., PRL 102, (2009) Skin(Sn): Chen et al., arxiv:1004/4672 (2009) E sym S o L K B sym B E L 30 sym B B 0 3 P 0 sym

29 Constraints on the density dependence of symmetry energy? Au+Au

30 Constraints on the density dependence of symmetry energy at supra normal density Au+Au experiments in high energy are not designed to measure symmetry energy Need better experiments

31 SEP: a comprehensive scientific program to span a large range of densities at different facilities E/A=1600 MeV 200 MeV 50 MeV Pions, n, p fragments

32 Comprehensive Experimental Programs by SEP (international collaboration) MSU 09- RIBF 12, FRIB 17 GSI 11 FAIR scientific program spans density range from 0.3 to 3 o at different facilities

33 SE Observables at High Energy (density) I. Double ratio: pion production R p / Y Y p Sn Sn / Sn Sn p / Yp p / Yp II. n/p or t/3he flows. Yong et al., Phys. Rev. C 73, (2006) B.-A. Li et al., Phys. Rep. 464 (2008) 113.

34 New Detectors needed: n detectors: NSCL/pre-FRIB; GSI; RIBF/Riken Pions/kaons & p, t, 3 He detectors: TPC NSCL Dual purpose AT-TPC: TPC funded via MRI by NSF RIBF TPC: SUMARAI magnet funded, TPC Japan-US collaboration: funded by DOE ($1.2M). AT-TPC: FRIB ~ 1.2 M TPC ~ 0.8 M Travel: 0.4 M

35 Symmetry Energy Project (SEP) collaboration Determination of the Equation of State of Asymmetric Nuclear Matter MSU: B. Tsang & W. Lynch, G. Westfall, P. Danielewicz, E. Brown, A. Steiner Texas A&M University : Sherry Yennello, Alan McIntosh Western Michigan University : Michael Famiano RIKEN, JP: TadaAki Isobe, Atsushi Taketani, Hiroshi Sakurai Kyoto University: Tetsuya Murakami Tohoku University: Akira Ono GSI, Germany: Wolfgang Trautmann, Yvonne Leifels Daresbury Laboratory, UK: Roy Lemmon INFN LNS, Italy: Giuseppe Verde, Paulo Russotto GANIL, France: Abdou Chbihi CIAE, PU, CAS, China: Yingxun Zhang, Zhuxia Li, Fei Lu, Y.G. Ma, W. Tian 5th RIKEN PAC recommends completion of TPC in 2013 DOE FOA award $1.2 M includes US contributions to SAMARAI TPC 10/1/2010 9/30/2015

37 Design of New TPC chamber Alan McIntosh (Texas A&M University) Based on EOS TPC At FNAL in Aug 2010 Known technology

38 Texas A&M + MSU+WMU RIKEN+ Kyoto University Alan McIntosh Bill Lynch Fei Lu Jimmy Dunn (UG) Jon Gilbert (UG) Jon Barney (UG) Michael Famiano TadaAki Isobe Atsushi Taketani Hiro Sakurai Tetsuya Murakami

39 Conceptual Design of the TPC detector Alan McIntosh, Bill Lynch, Jimmy Dunn (UG), Jon Gilbert (UG), Jon Barney (UG) Electronics and pad plane Field Cage TPC chamber

40 Electronics on the move: Zibi Chajecki, Jack Winkelbauer

NSCL experiments 05049 & 09042 Density dependence of the symmetry energy with emitted neutrons and protons & Investigation of transport model parameters (May & October, 2009 ) facility Probe Beam

41 NSCL experiments & Density dependence of the symmetry energy with emitted neutrons and protons & Investigation of transport model parameters (May & October, 2009 ) facility Probe Beam Energy Travel (k) $ year density MSU n, p,t,3he < o GSI S394, May 2011 GSI n, p, t, 3He / o MSU iso-diffusion < o RIKEN iso-diffusion < o MSU p +,p o RIKEN n,p,t, 3 He,p +,p o GSI n, p, t, 3He o FRIB n, p,t, 3 He, p +,p o FAIR K + /K ? o NSCL experiment Precision Measurements of Isospin Diffusion, June 2011)

42 n/p Experiment 124 Sn+ 124 Sn; 112 Sn+ 112 Sn; E/A=50 MeV Famiano et al Mike Youngs & Dan Coupland thesis expts 124 Sn+ 124 Sn; 112 Sn+ 112 Sn; E/A=120 MeV 48,40 Ca+ 112,124 Sn; 48,40 Ca+ 112,124 Sn

NSCL experiment 07038 & RIKEN (2012) Precision Measurements of

Target E/A lab 124,118,112Sn 124,118,112Sn 50 NSCL

43 NSCL experiment & RIKEN (2012) Precision Measurements of Isospin Diffusion (Jack Winkelbauer, June 2011) Projectile Target E/A lab 124,118,112Sn 124,118,112Sn 50 NSCL 124,112,108Sn 124,112Sn 50 RIKEN NSCL transport simulation meeting twice a month

44 Milestone in Management Plan

45 Summary The density dependence of the symmetry energy is of fundamental importance to nuclear physics and neutron star physics. Observables in HI collisions provide unique opportunities to probe the symmetry energy over a range of density especially for dense asymmetric matter Calculations suggest a number of promising observables that can probe the density dependence of the symmetry energy. Isospin diffusion, isotope ratios, and n/p spectral ratios may provide some constraints at ρ ρ 0, π + vs. π - production, neutron/proton spectra and flows may provide constraints at ρ 2ρ 0 and above. The availability of intense fast rare isotope beams at a variety of energies at RIKEN, FRIB & FAIR allows increased precisions in probing the symmetry energy at a range of densities Symmetry Energy Project (SEP); international collaboration of a global program.

46 Involvement of undergraduate students Jon Barney Jimmy Dunn Jon Gilbert

Experimental Observables to study the nuclear symmetry energy with Heavy Ion Collision

Experimental Observables to study the nuclear symmetry energy with Heavy Ion Collision Heavy Ion Meeting April 13, 212 Pohang, Korea Betty Tsang The National Superconducting Cyclotron Laboratory Michigan