nuclear eos at low density

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ECT*, Trento 2013 A. Chbihi 1 Nuclear EOS at low density Abdou Chbihi GANIL

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Nuclear EOS at low density. Abdou Chbihi GANIL. Nuclear EOS at low density. EOS is the fundamental property of NM that descibes the relationships between E, P, T, r, d for nuclear system. Improved understanding of the S( r ) will provide : Masses, Fission barriers, - PowerPoint PPT Presentation

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Page 1: Nuclear EOS at low density

ECT*, Trento 2013 A. Chbihi 1

Nuclear EOS at low density

Abdou ChbihiGANIL

Page 2: Nuclear EOS at low density

Nuclear EOS at low density• EOS is the fundamental property of NM that descibes

the relationships between E, P, T, r, d for nuclear system

ECT*, Trento 2013 A. Chbihi 2

• Improved understanding of the S(r) will provide :o Masses,o Fission barriers, o Energies of isovector collective vibrations,o Thickness of the neutron skins of neutron rich exotic nucleio Impact on astrophysics

Page 3: Nuclear EOS at low density

Nuclear EOS at low density

ECT*, Trento 2013 A. Chbihi 3

• Neutron stars and type II supernovae are composed of macroscopic quantities of asymmetric NM at wide range of densities.

• Experimental information on EOS can help improving predictions of neutron star observables (satellite observatories) : o Stellar radii,o Moments of inertia,o Crustal vibration frequencies, o neutron star cooling rates

• Major theoretical uncertainties are due to absence of strong constraints on Esym of the EOS

• Constraints derived from NS observations should be supported by laboratory measurements (effective interaction)

Page 4: Nuclear EOS at low density

ECT*, Trento 2013 A. Chbihi 4

Exploring the density dependence of symmetry energy with heavy-ion collisions

Intermediate energiesMultifragmentationProbe subsaturation density

High energiesSuprasaturation density

soft

stiff

Density ρ/ρ0GANILRIKENMSULNSGSI

GSIRIKEN Eincident

Intermediate energiesPeripheral and semi peripheral collisionssaturation density

78Kr : 0.4692Kr : 4.35

Page 5: Nuclear EOS at low density

ECT*, Trento 2013 A. Chbihi 5

• At low densities reachable at GANIL, LNS, MSU, GSIoIsotopic distribution of complex fragments (GANIL, LNS, MSU)oIsoscaling of the nuclear multi-fragmentation (GANIL, LNS, MSU, GSI)oIsospin diffusion (MSU, Chimera at LNS, GANIL)oPre-equilibrium neutron/proton (MSU, GSI)oSpectra of light cluster 3H/3He (MSU, GANIL)oSpectra mirror nuclei 7Li/7Be (MSU, GANIL)oDifferential flow (GSI, MSU)oCorrelation functions at low momentum (HBT, MSU, LNS)

• At high densities reachable at RIKEN and GSIoNeutron-proton differential transverse flowoNeutron/proton mid-rapidity emissionop- and p-/p+ ration,oK-/K0 ratio

Probes of the density dependence of symmetry energyby studying heavy-ion collisions and N/Z d.o.f.

Page 6: Nuclear EOS at low density

A. Chbihi 6

Accessing the symmetry energyoutline

• From the isotopic distributions– SMF predictions – AMD predictions– Experiments 40,48Ca+40,48Ca @ E/A = 35 MeV (INDRA-

VAMOS)• From the ratio 3H/3He

– SMF predictions– Experiments 124,129Xe+112,124Sn @ E/A = 65-250 MeV

(INDRA@ GSI)• Conclusions

ECT*, Trento 2013

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Accessing the symmetry energyfrom isotopic distribution

SMF predictions

• Full SMF simulations in a box for unstable matter allows the fragment formation

• Analysis for local density at the freeze-out: – The isovector variance for cells

having the same density– if the equilibrium is obtain F will

corresponds to the symmetry energy.

ECT*, Trento 2013

freeze-out

ρ

F’ ~ T / σ

T = 3 MeV, Density: ρ1 = 0.025 fm-3 , 2ρ1 , 3ρ1

Page 8: Nuclear EOS at low density

A. Chbihi 8

– The Esym increases with density and the trend is more pronounced with stiff,

– In general, low density ->low sym ener -> large variance

– we should see this feature in the isotopic distribution of the fragment as well as in the LP.

ECT*, Trento 2013

F’ follows the local equilibrium value !

stiff

soft

Accessing the symmetry energyfrom isotopic distribution

SMF predictions

Page 9: Nuclear EOS at low density

ECT*, Trento 2013 A. Chbihi 9

Accessing the symmetry energyFrom isotopic distributions…

AMD simulations: 40Ca+40Ca,48Ca+48Ca,60Ca+60Ca,46Fe+46Fe E/A=35 MeV and b=0 Primary fragment distributions

A. Ono et al., Phys. Rev. C70, 041604(R) (2004)

K(N,Z) : a global isotopic distribution constructed by combining all yield of the frag. obtained in the 4 sys

Page 10: Nuclear EOS at low density

ECT*, Trento 2013 A. Chbihi 10

Accessing the symmetry energy

- z(Z) independent of Z (negligible surface effect) symmetry energy of INM- Probe density dependence of Csym(r) at subsaturation densities r<r0

A. Ono et al., Phys. Rev. C70, 041604(R) (2004)

statistical treatment

Page 11: Nuclear EOS at low density

A. Chbihi 11ECT*, Trento 2013

Effects of secondary decaysPrimary Secondary a=A/8 Secondary a=A/16

z(Z)

z(Z) z(

Z)

Z Z Z5 10 15 15 1510 105 5

Secondary decays need to be taken into account for comparison to experimental data (use of Statistical calculation.

Or/and : experimentally provide the primary distributions

A. Ono, Acta Physica Hungarica A - Heavy Ion Physics, in press

Page 12: Nuclear EOS at low density

ECT*, Trento 2013 A. Chbihi 12

Page 13: Nuclear EOS at low density

ECT*, Trento 2013 A. Chbihi 13

Symmetry energy experiments• 40Ca + 40Ca @ E/A = 35 MeV• 40Ca + 48Ca @ E/A = 35 MeV isospin diffusion• 48Ca + 40Ca @ E/A = 35 MeV isospin diffusion• 48Ca + 48Ca @ E/A = 35 MeVFor Br (Tm)= 2.2 , 2.12 , 1.957 , 1.80 , 1.656 , 1.523 , 1.401 , 1.289 , 1.186 ,

1.091 , 1.004 , 0.923 , 0.849 , 0.782 , 0.719 , 0.661Isospin dependence of level density experiments (N. Le Neindre)• 40Ar + 64Ni @ E/A = 12.7 MeV (104Pd)• 40Ar + 60Ni @ E/A = 12.7 MeV (100Pd)• 34Ar + 58Ni @ E/A = 13.5 MeV (92Pd)• 36Ar + 58Ni @ E/A = 13.3 MeV (94Pd)• 36Ar + 60Ni @ E/A = 13.3 MeV (96Pd)

Experiments coupling INDRA-VAMOS

Page 14: Nuclear EOS at low density

ECT*, Trento 2013 A. Chbihi 14

INDRA

Q1Q2

Dipole

beam

detection

VAMOS PLF (E503) or residues (E494s)High Isotopic Resolution

INDRA in coincidence LCP /IMF event characterization (b, excitation energy)

Page 15: Nuclear EOS at low density

A. Chbihi 15

INDRA-VAMOS

ECT*, Trento 2013

INDRA : • all charged

products, 7°<Q<176°, MINDRA≥1

• Z, Q, F, Ek and A for Z<5

• Impact parameter and excitation energy estimation.

VAMOS Spectrometer: • 2°<Q<7°, MVAMOS = 1• PLF : A, Z, Q, F, velocity, Q etc. • Full trajectory reconstruction.

Page 16: Nuclear EOS at low density

ECT*, Trento 2013 A. Chbihi 16

40Ca + 48Ca @ 35 MeV/AZ=N

BNF C

ONeNa MgAlSiP SClArKCa

BeLi

Result @ given Br and for a given Si detector

VAMOS Spectrometer

INDRA

Page 17: Nuclear EOS at low density

A. Chbihi 17

Global view of the reaction products

ECT*, Trento 2013

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A. Chbihi 18

Isotopic distributions of PLF

ECT*, Trento 2013

• Broad APLF distributions• Sensitive to the n-richness of the system• N/Z up to 1.58 (11% N/Z 48Ca)

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Reaction mechanism at fermi energy

• Peripheral collisions : – a few nucleons exchanges– The PLF/TLF can be moderately excited and decay by a few LP

• Semi-peripheral collisions : – P and/or T breackup into two or more fragments– The PLF/TLF can be moderately excited and decay by a few LP

• Central collisions : production of fragments (multifragmentation)

ECT*, Trento 2013

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Characteristics of LCP emitted in coincidence with the PLF

ECT*, Trento 2013

• Two components drawing coulomb rings:• One centered on the PLF velocity (origin)• Second centered on the TLF.• Velocity selection to associate LCP and PLF emitted from the same PLF• VCM>0

proton alphaZPLF = 20

Page 21: Nuclear EOS at low density

A. Chbihi 21ECT*, Trento 2013

Toward the primary fragment reconstructionCombining PLF and LCP information

• Small multiplicitiesproton and alpha up to 1.5

• Moderate Ex*

• Trend in agreementwith n-richness of the system

Page 22: Nuclear EOS at low density

A. Chbihi 22

Primary charge of the fragments

ECT*, Trento 2013

ZPLF can reconstruct different Zprimary

ORZprimary can populate different ZPLF

On average 2 charge units transfer

Page 23: Nuclear EOS at low density

A. Chbihi 23ECT*, Trento 2013

Toward primary mass of the fragments

Zprimary = 18Zprimary = 20

Zprimary = 16Zprimary = 12

is not measured

Can be used as an observable

Page 24: Nuclear EOS at low density

A. Chbihi 24

How to obtain Aprimary distributions ?• Impossible without measuring the neutrons• Even if we measure the neutron, their efficiency is

poor, we cannot reconstruct the Aprimary in event/event basis

• Simulation with statistical model GEMINI (R. Charity)– ZPLF, Zprimary, (Aprimary-Nn), (kinetic energy of LCP)

experimental quantities– For each measured Zprimary -> mapping of (Aprimary, E*) – Fit -> Weight to each Zprimary, Aprimary, E* which

reproduce ZPLF, APLF, MLCP, Ek LCP

• Simulations are in progress. ECT*, Trento 2013

Page 25: Nuclear EOS at low density

A. Chbihi 25ECT*, Trento 2013

First tests of the method

Page 26: Nuclear EOS at low density

A. Chbihi 26

Symmetry energy from primary fragments

ECT*, Trento 2013

Page 27: Nuclear EOS at low density

A. Chbihi 27ECT*, Trento 2013

Preliminary results on Symmetry energy

Esym/T for Apr and Apr-Nnare similar; for 40Ca+40Ca

As expected different for APLF

Esym/T = 10, Zpr = 20is compatible with Esym=27 MeVif one assumes T=2.5 MeV, and density close to the saturation

Need to estimate the temperatures for the other Zprfrom Ek of LCP

Page 28: Nuclear EOS at low density

A. Chbihi 28

Production cross section of exotic nuclei beyond the drip lines

ECT*, Trento 2013

Decay modesCP, n, g… spectroscopy

40Ca+40Ca

Page 29: Nuclear EOS at low density

A. Chbihi 29ECT*, Trento 2013

Production cross section of exotic nuclei beyond the drip lines

48Ca+48Ca

Page 30: Nuclear EOS at low density

ECT*, Trento 2013 A. Chbihi 30

INDRA@GSI experiments124,129Xe+112,124Sn @ E/A = 64-250 MeV

Probe : Spectra of light cluster 3H/3He

Famiano et al. PRL97.052701, 2006

Page 31: Nuclear EOS at low density

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Study of Light Fragment Emission: 136,124Xe+124,112Sn, E = 32,.,150 AMeV , Single yield ratios

son: asysoft, mn*>mp* stn: asystiff, mn*>mp* sop: asysoft, mn*<mp* stp: asystiff, mn*<mp*

Single ratio n/pneutron rich

Single ratio t/3Heneutron rich

Single ratio n/pneutron poor

Effects smaller For light clusterst/He

Smaller neutron excess: effects smaller

E=32 AMeV E=65 AMeVAsyEOS – eff mass dominates

Possibility to separate density and momentum dependence of symmetry energy

E=150 AMeV

Etransverse/A

E=150 AMeV

ECT*, Trento 2013

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A. Chbihi 32

Study of Light Fragment Emission: 136,124Xe+124,112Sn, E = 32,.,150 AMeV , Double yield ratios

Single ratio n/pneutron poor

Double ratio n/pneutron richneutron poor

Effects smaller For neutron poor system

Double ratio also shows effect but less sensitive to symmetry energy

E=32 AMeV E=65 AMeVAsyEOS – eff mass dominates

Possibility to separate density and momentum dependence of symmetry energy

E=150 AMeV

Etransverse/A

E=150 AMeV

son: asysoft, mn*>mp* stn: asystiff, mn*>mp* sop: asysoft, mn*<mp* stp: asystiff, mn*<mp*

Single ratio n/pneutron rich

ECT*, Trento 2013

Page 33: Nuclear EOS at low density

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Etr spectra and ratio 3H/3Hefor 129,124Xe+124,112Sn @ E/A = 100 MeV

124,129Xe+112,124Sn @ E/A=100 MeVCentral collisions (b<0.1 bmax)

70°< Qcm<110°

3H

3He

Etr (MeV/A)

The interval 40<Etr (MeV/A)<60Yield ratio independent of cluster energy-> free of spurious effects (evaporation etc.)

ECT*, Trento 2013

Page 34: Nuclear EOS at low density

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Excitation function of 3H/3He The ratio 3H/3He is taken in the interval [40,60] MeV/A of Etrans spectra

• Yield ratio at mid-rapidity in central collisions is nearly constant.

• If corrections for Coulomb effects are included, the 3H/3He ratio is only sensitive to N/Z -> Esym

As measured

Coulomb correction

Einc/A (MeV)

ECT*, Trento 2013

Page 35: Nuclear EOS at low density

• Exploration of Esym(r) with HI-Collisions• Accessing the symmetry energy from

– Primary experimental isotopic distributions– isospin diffusion– 3H/3He ratio

ECT*, Trento 2013 A. Chbihi 35

Summary and Conclusions

Page 36: Nuclear EOS at low density

ECT*, Trento 2013 A. Chbihi 36

A. Chbihi, G. Verde, J.D. Frankland, J. Moisan, B. Sorgunlu, F. Rejmund, M. Rejmund, J.P. Wieleczko, Sarmishtha Bhattacharya, P. NapolitaniGANIL, CEA, IN2P3‑CNRS, FRANCE

INFN, Catania, ITALYE. Bonnet, B. Borderie, E. Galichet, N. Le Neindre, M.F. Rivet

IPN Orsay, IN2P3‑CNRS, FRANCE R. Dayras, L. Nalpas, C. Volant

DAPNIA/SPhN, CEA Saclay, FRANCED. Guinet, P. Lautesse

Institut de Physique Nucléaire, IN2P3‑CNRS et Université, Caen Cedex, FRANCER. Bougault, O. Lopez, B. Tamain, E. Vient

LPC. IN2P3‑CNRS. ENSICAEN et Université, Caen Cedex, FRANCEA. Ono

Department of Physics, Tohoku University, Sendai, JAPANR. Roy

Université de Laval, Quebec, CANADAW. Trautmann, J. Lukasik

GSI, D-64291 Darmstadt, GERMANYE. Rosato, M. Vigilante

Dipartimento di Scienze Fisiche, Un. Federico II, Napoli, ITALYM. Bruno, M. D’Agostino, E. Geraci, G. Vannini

INFN and Dipartimento di Fisica, Bologna ITALYL. Bardelli, G. Casini, A. Olmi, S. Piantelli, G. Poggi

INFN and Dipartimento di Fisica, Firenze,ITALYF. Gramegna, G. Montagnoli

INFN, Laboratori Nazionali di Legnaro, ITALYU. Abbondanno

INFN, Trieste, ITALYM. Parlog, G. Tabacaru

National Institute for Physics and Nuclear Engineering, Bucarest‑Maguerele, ROMANIASaila. Bhattacharya, G. Mukherjee

Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata, INDIA

Paola Marini, Mark Boisjoli

Page 37: Nuclear EOS at low density

A. Chbihi 37ECT*, Trento 2013

Preliminary results on Symmetry energy

Esym/T for Apr and Apr-Nnare similar; for 40Ca+40CaBut different for APLF