Exochim & Farcos collaboration:L. Acosta, F. Amorini, A. Anzalone, L. Auditore, G. Cardella, A. Chbihi, E. De Filippo, L. Francalanza, E. Geraci, C. Guazzoni, E. La Guidara, G. Lanzalone, I. Lombardo, S. Lo Nigro, D. Loria, I. Martel, T. Minniti, E.V. Pagano, A. Pagano, M. Papa, S. Pirrone, G. Politi, F. Porto, F. Rizzo, P. Russotto, S. Santoro, A. Trifirò, M. Trimachi, G. Verde, M. Venhart, M. Veselsky, M. Vigilante

NSCL-Michigan State UniversityZ. Chajecki, P. Danielewicz and B. Barker

Acknowledgements

Dynamics and correlation studies @ INFN-Catania

CataniaLNS

Tandem (15 MV) EA ≤ 10 MeV Superconducting Cyclotron

K800

G. Verde & Exochim coll., INFN-CT, INFN-LNS, Univ. of Catania, LNS

Chimera… our “Alice” for intermediate energies…

1m

1°

30°

TARGET

176°

Beam1192 Si-CsI(Tl) Telescopes 18 rings in the range 1° ≤ θ ≤ 30°

17 rings in the range 30° ≤ θ ≤ 176° (sphere)High granularity and efficiency up to 94% 4π

• Z identification up to beam charge (ΔE-E)• Z and A identification by ΔE-E up to Z ≤ 9• Z and A identification in CsI up to Z ≤ 4• Mass identification with low energy threshold (< 0.3 MeV/u) by ToF• Z identification for particles stopping in Si (pulse shape)

SiCsI(Tl)

ΔE(Si)-E(CsI)

Charge Z for particles punching throught the Si detector

PSD in CsI(Tl)

Z and A for light charged particles

ΔE(Si)-ToF

Mass for particles stopping in the Si detector

E(Si)-Rise time

Charge Z for particle stopping in Si detectors (NEW)

ΔE(Si)-E(CsI)

Charge Z and A for light ions (Z<9) punching throught the Si detector

HI

pd

t

3Hea

LiBe

~300 μm

3-12 cm

V(t)

t

gate

fast

slow

Particle identification in Chimera

Farcos project: femtoscopy capabilities

Stay tuned!

Talk by T. Minniti, INFN-CT and University of Messina

What do you mean by “low energies”?

Dynamics/Thermodynamics

EoS, Asy-EoS

Space-time probes required (Two-particle correlations, Femtoscopy, emission chronology, time-scales, etc.)

Intermediate energies:E/A=30-100

MeV

Medium (GSI) energies:E/A=200-1500

MeV

High energy Vs. “low” energies

• Different interpretations, different models, different physics goals (not always, i.e. elliptic flow etc.), …

• Similar space- and time-scales involved:– R ~ 2-10 fm– τ ~ 2-104 fm/c

Share analysis techniques, ideas, detection technologies…

The EoS of asymmetric nuclear matter

Infinite nuclear matter: how does E depend on density?

???B.A. Li et al., Phys. Rep. 464, 113 (2008)

Many approaches… large uncertainties….

Microscopic many-body, phenomenological, variational, …

Asy-Stiff

Asy-Soft

Producing density gradients in HIC

SMF - Baran, Colonna, Di Toro, Greco

Intermediate energies: E/A=20-100 MeV

Ganil, Eurisol, Frib, Lns, Nscl, Spiral2, Tamu, …

High energies: E/A>200 MeV

CSR, GSI/Fair, NSCL/FRIB, Riken, …

Neutron Stars• Radii• Frequencies of crustal vibrations

• Composition, thickness of inner crust

• URCA processes• Phases within the star

Densities ~ 0.01ρ0 - 6ρ0 – Large Gradients!!!

Probes of the symmetry energy• Probes at Intermediate energies: sub-saturation

density Asy-EoS (ρ<ρ0)– Isospin diffusion and drift– Neutron-proton pre-equilibrium emission– nn, np, pp correlation functions

• Probes at GSI energies: supra-saturation density Asy-EoS (ρ>ρ0)– π+/π- and K+/K0 emission ratios– n/p elliptic flow– n/p pre-equilibrium emission

ρ0~ 0.17 fm-3

Effects of the Esym at high density

• N/Z of high density regions sensitive to Esym(ρ)• High ρ>ρ0 : asy-stiff more repulsive on neutrons -

opposite of sub-saturation trend

stiffness stiffness

B.A. Li et al., PRC71 (2005)

≈(ρ/ρ0)γ

1

0 )(cos212

),()( n

RntR

nvNpyddN

2

22

2 ),(t

yxt p

pppyV

Elliptic flow: competition between in plane (V2>0) and out-of-plane ejection (V2<0)

z

xV2

y

Y = rapiditypt = transverse momentum

High densities: flows

UrQMD vs. FOPI data:Au+Au @ 400 A MeV5.5<b<7.5 fm

Qingfeng Li, J. Phys. G31 1359-1374 (2005) P.Russotto et al., Phys. Lett. B

697 (2011)

ASY-EOS experiment (May 2011)“possible“ 1st phase toward FAIR ???

(e.g. 132Sn,106Sn beams)

Au+Au @ 400 AMeV96Zr+96Zr @ 400 AMeV 96Ru+96Ru @ 400 AMeV

~ 5x107 Events for each system

ASY-EOS S394 experiment @ GSI Darmstadt (Germany)

Beam Line

Shadow Bar

TofWall

Land(not splitted)

target

ChimeraKrakow array

MicroBall

P. Russotto, INFN-CT

Chimera for event shape: reaction plane, impact parameter

LAND: neutrons and protons elliptic flow

P. Russotto, INFN-CT

g32new

Kinematics Centrality dependence

sorted using transverse energy of LCP (Z≤2)

Au+Au @ 400 AMeV

projmid

preliminary

P. Russotto, INFN-CT

Pion ratios: controversial results….

Zhigang Xiao et al.PRL 102 (2009)

IBUU04: Supersoft IBUU04

ImQMD: superstiff

Zhao-Qing Feng, Gen-Ming Jin, Phys.Lett.B683, 2010

????

Pion and Kaon freeze-out in HIC

Warning with pions:• Strongly interacting in medium

• Freeze-out at late times (low ρ/ρ0)

• Difficult to isolate π+ and π- produced in the high density stage

Low ρ/ρ0 High ρ/ρ0

Kaons: more sensitive probes?• Higher thresholds• Weakly interacting in medium• Freeze-out already at 20 fm/c: real

high density region probes

K+,K0π+, π-

RBUU, Ferini et al., PRL97, 202301

HIC at Fermi energies: Esym(ρ) at ρ<ρ0

b=peripheral

PLF

TLF

Isospin diffusion & drift

Pre-equilibrium emission Expansion Multifragmentationb=central

b=mid-peripheral Neck fragments

PLF

TLF

Neck, low ρ, isospin drift

1

3

4

2

Isospin diffusion

TLF PLFNeck

N/ZPρoj

Taρg

n/p diffusion

Isospin drift & diffusion

ρ ~1/8ρ0

ρ~ρ0

ρ ~ρ0

n drift

Isospin drift

TLF PLFNeck

ρ/ρ01

Esym vs ρ

Asy-Stiff

Asy-Soft

Low ρ<ρ0

Isospin equilibration

Long τint

Isospin translucency

Short τint

Proj

Targ

TLF

PLFPLF

TLFTLF

PLF

Colonna et al.; Danielewicz et al.

Event characterization

TLF PLFIMF TLF PLFIMF TLF ~ PLF~ IMF

Characterize IMF emission IMF times

3Mc6

*bred>0.6

7Mc12

0.2<*bred<0.6 Mc>12

*bred<0.2

124Sn+64Ni @ 35 MeV/u

TLF seq. emission

Time-scales from three-fragment correlations

PLF seq. emission

Vrel (IMF-PLF) / VViola

V rel (

IMF-

TLF)

/ V Vi

ola

PLF TLF

IMF intermediate

TLFPLF

IMF

Prompt emissionfrom neck

1

Emission time-scales and chronology

12

3

2 80 fm/c

1 40 fm/c

3 120 fm/c

Light fragments are produced earlier than heavier ones

~40 fm/c vs ~120 fm/c

Simultaneous

Sequential

E. De Filippo, P. Russotto, A. PaganoPhys. Rev. C (2012)

Isospin chronologyLi Be

B C

<N/Z

>

124Sn + 64Ni 35 A.MeV Prompt emissions more neutron rich

neutron-enrichment in neck emissions

E. De Filippo, P. RussottoPRC (2012)

Isospin chronology and symmetry energy

“Quasi”-Asy-Stiff (γ~0.8) more consistent with experimental results

E. De Filippo, A. Pagano, P. Russotto et al., Phys. Rev. C (2012)

Femtoscopy in HIC

p-p

Hodo56 @ NSCL

n-nEDEN @ LNS

γ-γMEDEA@ GANIL

LCP-IMF

INDRA @ GANIL

IMF-IMF

Chimera @ LNS

d-α

Lassa @ NSCL 1+R(

q)

0.6

1.2

q (MeV/c)100 20000

HODOCT/Aladin @ GSI

p-α

p-p

FOPI@ GSI

NN correlations and symmetry energy

IBUU simulations 52Ca+48Ca E/A=80 MeV Central collisions

Proton/neutron emission times sensitive to density dependence of the symmetry energy

Asy-stiff

Correlation functions

neutron-neutron

proton-proton

0.0

0.5

1.0

1.5

1

2

3

4

1

3

5

7

q (MeV/c)

1+R(

q)

proton-neutron

Asy-soft

Lie-Wen Chen et al., PRL (2003), PRC(2005)

Neutron-proton emission chronology

Time delay between emissions Δt≠0 - Example: p emitted first

pp

p

n

Vp > Vn

n

p

Vp < Vn

Stronger interaction“particle catch-up”

Interaction attenuated

Lednicky recipe: p-n correlations1+R+(q)

1+R−(q)

Ratio +/-

Ratio R+/R- tells us which is emitted first

R. Lednicky et al., Phys. Lett. B373, 30 (1996)

Nuclear FSI

q (MeV/c)q (MeV/c)q (MeV/c)

n first +100 fm/cn first +50 fm/cp first -100 fm/c

p-n p-n p-n

Isospin effects on p-p

R 48Ca+ 48Ca > R 40Ca+ 40Ca

48Ca+48Ca vs 40Ca+40CaE/A=80 MeV - Central

Correlations Emitting sources

Larger size for more n-rich system: N/Z effect? Size effect? Asy-EoS? σNN

Z. Chajecki, et al. Phys. Rev. C (2012)

Multi-Particle Correlation Spectroscopy (MPCS) – “non-femtoscopic” stuff…

HIC and correlations as a spectroscopic tool

• Cluster states in stable and exotic nuclei• BEC, Hoyle

Expansion

Not only EoS…

Several unbound species in just one single experiment!

10C*

8B unbound state: spin determination

States of 8B p+7Be

p+7Be

0.774

1.4 (?)

2.32

8B1+

3+

p-7Be correlations

W.P. Tan et al. Phys. Rev. C69, 061304 (2004)

7Be

8B p

Xe+Au E/A50 MeV Central collisions

Sequential decay modes: multi-particle correlation functions

• Peripheral projectile fragmentation12C+24Mg E/A=53, 95 MeV (Indra@GANIL)Decay of 12C and 10C quasi projectiles (QP*)

12C* α + α + α 10C* α + α + p + p

α + 8Be

α + α

2p+8Be

α+α

p+9B

α+ α+p

α+6Be

α+2p

2α+2pdirect

α + α + α

direc

t

Hoyle states?Boson condensate?

2α-2p correlations : states in 10C*

Ek(MeV)

10C 6Be+α (2p+α)α10C 8Be+p+p (α+α)+p10C 9B+p (+αα)pF. Grenier et al., Nucl. Phys.

A811 (2008) 233

Search for Hoyle states in Nα nuclei

Three-alpha correlations12C* α + α + α

Gated 8Be* α + α

No direct three-body decay of Hoyle state in 12C

J. Manfredi, R.C. Charity et al., PRC 2012 A. Raduta et al., Phys. Lett. B705, 65, 2011

40Ca+12C, E/A=25 MeV @ Chimera

12C 3 alpha

Γ~ 7.5% direct three-body decay (BC?)

Conclusions• Probes of symmetry energy at high density:

– GSI energies: n/p flow Chimera-LAND@GSI– π+/π- and K+/K0 emission ratios– Understand where and when π’s and K’s are

produced… correlation techniques (?)• Probes of symmetry energy at low density:

– Intermediate energies: Isospin diffusion and drift; moderately soft symmetry energy (γ~0.6-0.9)– Still missing probes from femtoscopy future projects

• “non-femtoscopic” correlations to learn about new phenomena and exotic nuclear systems