Femtoscopy and dynamics/ intermediate energies

• Imaging “Femtoscopy”

• Transport models / Asy-EOS

• Complex particle correlations

• Our future

R~1-10fm~10-21-10-15sec

G. Verde, INFN, Italy

p-p correlations

S.E. Koonin, PLB70 (1977) 43S.Pratt et al., PRC42 (1990) 2646

Kernel = ( ) 12

−rq

rrψ

€

R(r q ,

r P ) = d

r r ⋅S r

P (r r )∫ ⋅K

r r ,

r q ( )

• = Source function

€

S r P (r r )

• If (not simultaneous)21 tt ≠

r0

⋅+≈ VrRL 0

Pr

M. Lisa, P

RL70 (1993)

Directional measurements at GSI energies

FOPI

•FOPI: central collisions @ 400 MeV/u

v ~ 2-3 fm

•ALADiN: Target spectators Au+Au @ 1 GeV/u

< 20 fm/c

Kotte et al., Eur. Phys. J.A 9 (1999)

Schwarz, NPA 681 (2001)

…these are short time scales

Long-lived emissions at intermediate energies

r0

⋅+≈ VrRL 0

Pr

Secondary decays: enormous elongations (>104 fm/c…)

Weak sensitivity to very long (Awes, Phys. Rev. Lett. 61, 1988)

Directional correlations cannot tell the full story…

Angle-averaged correlations: information content

q (MeV/c)

1+R

(q)

G. Verde et al., PRC65, 054609 (2002)

Dynamical fast source (pre-equilibrium)

Long-lived sources (evaporation, sec. decays, …)

Ytotal=Dynamical + Sec. Decays Yfast + Yslow

“Femtoscopes”… from the widths

20 40 60 800 100

q (MeV/c)

1+R

(q)

p-p

q (MeV/c)

1+R

(q)

1

2

3

1

4

Peak A

Peak B

d-

G. Verde et al., PRC65, 054609 (2002)

Source size (fm)

Width (M

eV/c)

p-pAngle-averaged

d-

Source size (fm)

Width (M

eV/c)

Peak A

Peak B

Imaging at intermediate energies

Ytotal=Dynamical + Sec. Decays Yfast + Yslow

dynamical source (pre-eq.)

Source size

evap. sources (sec. decays)

14N+197Au E/A=75 MeV

€

R(q) = 4π dr ⋅r2 ⋅S(r) ⋅K(r,q)∫G. Verde et al., PRC65, 069604 (2002)P. Danielewicz, D.A. Brown

What physics from imaging

1. Sizes from width of peaks

2. Relative contributions from long-lived emissions from integral of source (peak height)

Handle on secondary decays!

3. Entire source profile: probes of transport models (EOS, Asy-EOS,…)

Probing transport properties?Central Collisions

D.O. Handzy et al., PRL 75 (1995) 2916

Early comparisons to BUU failed:

Long-lived emitting sources not handled properly

USE IMAGED SOURCE TO RENORMALIZE BUU SOURCES

Imaging and transportAr+Sc central

eq

G. Verde et al., Phys. Rev. C67, 034606 (2003)

Handzy, Lisa (1994)

Imaged S(r) vs BUU S(r)

E/A=120 MeV

r (fm)

S(r)

(fm

-3)

Imaging Data

BUU free NN

BUU red NN

Models

Source shape sensitive to NN

pp source systematics in central collisions

S(r

)S

(r)

r (fm)

Imaged sources

• No E/A dependence

What do transport models say about it?

Apart

Siz

e (f

m)

• Size increases with nr. of participants

• Dynamical features

Central collisions - Imaging vs BUUKr+Nb bred<0.4

r (fm)

S(r

) (a

.u.)

S(r

) (a

.u.)

E/A=100 MeV

E/A=70 MeV

Imaging data

BUU free NN

BUU red NN

• Imaged sources reproduced by BUU with red NN

G. Verde, B. Barker,P. Danielewicz (2008)

• E/A independence

• Apart dependence

Kr+Nb BUU

Ar+Sc BUU

E/A=120 MeV 100 MeV 70 MeV

E/A=150 MeV 100 MeV

Probing dynamical early stages?

Back-tracing p emission in BUU

Protons emission time and transverse momentum

112Sn+124Sn E/A=50 MeV bred=0-0.4

time (fm/c)

dN/d

t

PT/m > 0.2

PT/m > 0.3

Early

Late

pp sources

High PT: shorter emission times and smaller source sizes

“Back-tracing” p emission as it is probed by HBT

PT > 0.2

No PT gate

r (fm)

S(r

) (f

m-3)

PT > 0.3 Early pp emitting source

Emission times and Asy-EOS

Asy-Stiff

Asy-Soft

Emmission times of neutrons and protons

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

IBUU:52Ca+48Ca E/A=80 MeV

Emitting source functions

r (fm)

S(r

) (f

m-3)

Asy-stiff

Asy-soft

Density dependence of symmetry potential in EOS

0

Vsy

m(M

eV)

Asy-Stiff

Asy-Soft

Isotopic effects on p-p imaging 40,48Ca + 40,48Ca E/A=80 MeV

Si strips X-Y CsI

Angular resolution !

HiRAHigh angular resolution required: accessing low q-values…

1+R

(q)

q (MeV/c)

Asy-stiff

Asy-soft

Collaboration: MSU, IU, WU

INFN Catania GANIL

N/Z effects on p-p correlation functions

r (fm)

S(r

) (a

.u.)

40Ca+40CaN/Z=1

r (fm)

S(r

) (a

.u.)

48Ca+48CaN/Z=1.4

q (MeV/c)

1+R

(q)

40Ca+40Ca N/Z=1

48Ca+48CaN/Z=1.4

E/A=80 MeV central

prelimr (fm)

S(r

) (a

.u.)

Sensitivity to Esym(),stopping, NN, asy-transport (IBUU)… in progress

Em. source more localized in N=Z than in N>Z

Neutron-proton correlation functions

neu

tro

n-p

roto

n

Ghetti et al, PRC 69 (2004) 031605Protons

Neutrons

… in memory of Tano Lanzano’…

Accessing emission chronology - high sensitivity to Asy-EOS

Verde, Chbihi, Ghetti, Helgesson, EPJA 30, 2006Verde, Chbihi, Ghetti, Helgesson, EPJA 30, 2006

Beyond pp correlations…

1+R

(E* )

E*(MeV)

p-p

d-

-6Li

• Chronology and Hierarchy: different particles emitted at different times

• Non-identical particle correlations relevant to pp correlations

•IMF emission times: talk by E. De Filippo tomorrow stay tuned!

IMF emission timesKr + Au

Emission time decreases with velocity

Evolutionary fragment emission mechanisms (EES predictions)

Miniball data, E

. Cornell et al., P

RL

75 (1995) 1475

-, p + A 8.0, 8.2, 9.2, 10.2 GeV/c

From surface to bulk emission (Liquid-gas phase transition?)

Surf

Bulk

ISiS data, L. Beaulieu et al., PRL84 (2000) 5971

Light complex particles• Dominated by nuclear short-range interaction

d- correl

q (MeV/c)

1+R

(q)

Distortions due to position/momentum correlations

Second peak attenuated

Collective motion and correlations

Position dependent velocity fields:

€

rq =

r q thermal +

r q coll (

r r )

Thermal

r (fm)

q (M

eV/c

)

G. Verde et al., Physics Letters B653, 12 (2007)

Thermal+Collective

q (M

eV/c

)

r (fm)

r-q correlations!(r-P correlations!)

•S = S(r,q)

•Line-shape of R(q) distorted and depending on T

d vs pp radii

q (MeV/c)

1+R

(q)

1+R

(q)

1+R

(q)

Ep>30 MeV

15 <Ep<30 MeV

0 <Ep<15 MeV

slow

medium

fast

r0=5.6 fm

r0=9.4 fm

r0=14 fm

p-p1+

R(q

)1+

R(q

)1+

R(q

)

Ed>40MeV E>45MeV

20<Ed<40MeV 25<E<45MeV

0<Ed<20MeV 0<E<25MeV

q (MeV/c)

fast

medium

slow

Xe+Au E/A=50 MeV bred<0.3

No Teffcorrection

Small Teff correction

Large Teff correction

r0=9 fm

r0=6 fm

r0=2.2 fm

d-

Sizes: pp vs d

d- sources more localized than p-p sources

14.00

9.40

5.60

9.00

6.00

2.20

0

2

4

6

8

10

12

14

16

Ecm gates

Siz

es (

fm)

pp

d

Different particles emitted at different time stages (hierarchy)

EES scenario (W. Friedmann)

Xe+Au E/A=50 MeV central

HIC as a spectroscopic tool• Several unbound states are produced in each collision

- reconstructed with correlations

Relative heights of peak heights sensitive to spin of 8Be states

LASSA dataT

. Wanpeng et al., P

RC

(2004)

8B*---> p+7Be F. Grenier, A. Chbihi, R. Roy, G. Verde et al., NPA, in print

Ek(MeV)Probe sequential decays 10C-->9B+p vs 10C-->6Be+

10C* ---> p+p+

C+Mg

INDRA

Conclusions

• Femtoscopy and imaging – Sizes, contributions pre-eq/evap

• Probing transport theories and back-tracing particle emissions

• Isotopic effects (N/Z) to access Asy-EOS - preliminary results on Ca+Ca data

• Extend to several particle species - reveal hierarchy and chronology

Active projects

• Chimera and Indra + Silicon strips (INFN, GANIL) improving angular resolution

• Fazia (Italy, France, Poland, Romania, Spain, UK, India)

- 4 detector with high isotopic resolution, PSA and digitalization, low thresholds- well suited to future Spiral2 experiments

• HiRA, LASSA+First (USA)presently exploring isospin and HBT physics

Acknowledgements• NSCL/MSU (P. Danielewicz, W.G. Lynch,

M.B. Tsang, Wanpeng Tan, K. Gelbke, B. Barker, REU students)

• HiRA groups (IU, MSU, WU)• LLNL (D.A. Brown)• INDRA group (A. Chbihi, J. Frankland et al.)• Laval University (F. Grenier, R. Roy)