heavy-ion dynamics at the fermi energy a theoretical point of view heavy-ion dynamics at the fermi...
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Heavy-ion dynamics at Heavy-ion dynamics at the Fermi energythe Fermi energyA theoretical point of A theoretical point of viewview
Heavy-ion dynamics at Heavy-ion dynamics at the Fermi energythe Fermi energyA theoretical point of A theoretical point of viewview
Laboratory for heavy-ion physicsLaboratory for heavy-ion physics Division of Experimental Physics RDivision of Experimental Physics Ruđeruđer
Bošković Bošković Institute, Zagreb, CroatiaInstitute, Zagreb, Croatia
Zoran Basrak
EWON Town Meeting, May 10 –12, 2007, Prague, Czek Republic
EWON
RRuđeruđer Bošković Bošković Institute – SUBATECH Institute – SUBATECH collaborationcollaboration
Introduction
The Fermi energy & BDC
QP properties
Mid-rapidity emission
Early energy transformation
Conclusions
Outlook
Talk overview
From Coul. barrier to ~20 MeV/u
Global properties Mean field governs collision dynamics The Pauli blocking “freezes” “hard” . NN collisions
Central collisions: Fusion
Peripheral collisions: Binary Processes
TOTTOT
FUSFUS
B.P.B.P.
The Fermi energy region
Expected global properties Weakened influence of the mean field With increasing energy larger phase . space opens to the NN collisions
Still holds:
Till early 90’s believed:
TOTTOT
FUSFUS
B.P.B.P.
TOTTOT
FUSFUS
Hot nuclei !!!Hot nuclei !!!
Binary Dissipative Collisions
– BDC opens around the Fermi energy
Irrespectively of - event centrality
- system size
- system asymmetry
V.M
etiv
ier
et a
l . (I
ND
RA
Co l
labo
rat i
o n),
Nuc
l . P
hys.
A67
2 (2
000)
357
.
TOTTOT
FUFU
SS
BDC reaction mechanism
A compact quickly evolving early . reaction phase (prior to scission)
By birth of the primary QP & QT . starts the second reaction phase
A two-stage process:
J. P
eter
et a
l ., N
u cl .
Ph y
s. A
593
(199
5) 9
5.
Reconstructed primary QP mass approxim. . equal to the projectile mass
QP emission in BDC’s
QP emission in BDC’s
J. P
eter
et a
l ., N
u cl .
Ph y
s. A
593
(199
5) 9
5.
Reconstructed primary QP mass approxim. . equal to the projectile mass
Thus obtained primary QP extremely hot
Y. -
G. M
a et
al . ,
Ph y
s. L
ett .
B39
0 (1
997)
41.
Ar (95 MeV/u) Ni
QP emission in BDC’s
J. P
eter
et a
l ., N
u cl .
Ph y
s. A
593
(199
5) 9
5.
Reconstructed primary QP mass approxim. . equal to the projectile mass
Thus obtained primary QP extremely hot
Y. -
G. M
a et
al . ,
Ph y
s. L
ett .
B39
0 (1
997)
41.
Ar (95 MeV/u) Ni
Dynamical emission component
Ph .
Eud
es, Z
. Bas
rak
a nd
F. S
ebi l
le, P
hys.
Rev
. C56
(19
9 7)
200 3
.Landau-Vlasov model simulation
Ar ( 65 MeV / u ) Al
Dynamical emission component
Ph .
Eud
es, Z
. Bas
rak
a nd
F. S
ebi l
le, P
hys.
Rev
. C56
(19
9 7)
200 3
.Landau-Vlasov model simulation
Ar ( 65 MeV / u ) Al
Ar ( 65 MeV / u ) Al
Dynamical emission component
Ph .
Eud
es, Z
. Bas
rak
a nd
F. S
ebi l
le, P
hys.
Rev
. C56
(19
9 7)
200 3
.Landau-Vlasov model simulation
Ar ( 65 MeV / u ) Al
Ar ( 65 MeV / u ) Al
F. H
adda
d e t
al . ,
Ph y
s. R
ev. C
60 (
199 9
) 03
1 603
.
Z dynam emiss
Z targ + Z proj
= 100
Dynamical emission component
Dem (%) =
SystemIncident
energy (MeV/u)
40Ar+27Al 41, 65
40Ar+107Ag 50, 75, 100
107Ag+40Ar 50
36Ar+58Ni 52, 74, 95
12OXe+129Sn 50, 75, 100
Statistical emission componentLandau-Vlasov model simulation
The geniune primary QP emission
Ar ( 65 MeV / u ) Al
Statistical emission component
Ph .
Eud
es a
nd Z
. Bas
rak,
Eu r
. Phy
s. J
. A 9
(20
00)
207.
Landau-Vlasov model simulationAr ( 65 MeV / u ) AlThe geniune
primary QP emission
Ar ( 65 MeV / u ) Al
D. Cussol et al., Nucl. Phys. A561 (1993) 298.
J. Peter et al., Nucl. Phys. A593 (1995) 95.
D. D
ore
et a
l. (I
ND
RA
Col
labo
rati
on),
Ph y
s. L
ett.
B49
1 (2
000)
15.Ar (95 MeV/u) + Ni INDRA experiment
analyzed in the 3 sources assumption
experiment
3 sources analyses
Proton reduced rapidity distribution
QP emission in BDC’s
Mid-rapidity emission in BDC’s
max. compression
max. compression
local equilibration
local equilibration
Co
nfi
gu
rati
on
sp
ace
Imp
uls
e sp
ace
pre-scission post-scission
Mid-rapidity emission in BDC’s
≈ pre-scission emissionMid-rapidity emission
max. compression
max. compression
local equilibration
local equilibration
Co
nfi
gu
rati
on
sp
ace
Imp
uls
e sp
ace
pre-scission post-scission
Early energy transformationEtot = Ecollect + Eintrin
Eintrin = Eexcit + Epotent
Decompression followed by abundant emission and fast system cooling.
Early energy transformationEtot = Ecollect + Eintrin
Eintrin = Eexcit + Epotent
Eexcit EEthth /A /A
Epotent EEcomprcompr /A /A
SystemIncident energy
(MeV/u)b/bmax
40Ar+27Al 41, 65 0, … (0.1) … 1
36Ar+58Ni 52, 74, 95 0, … (0.2) … 1
40Ar+107Ag 50, 75, 100 0, … (0.1) … 1
12OXe+129Sn 50, 75, 100 0, … (0.2) … 1
40Ar+107Ag 20, 30, 40, 45 0
40Ar+197Au 50, 75, 100 0
Decompression followed by abundant emission and fast system cooling.
- Asys = ~70 - ~250 nucl
- Aproj:Atarg = 1:1 – 1:5
- brel = 0, … (0.1) … 1
I. N
ovos
el, Z
. Bas
rak
et a
l. , P
hys.
Let
t . B
625
(200
5) 2
6.
Heat & compression
– Maximal compression at ~25 fm/c
– In each volume cell a local equilibration at ~35 fm/c
– System scission at ~55 fm/c
I. N
ovos
el, Z
. Bas
rak
et a
l. , P
hys.
Let
t . B
625
(200
5) 2
6.
Heat & compression
– Maximal compression at ~25 fm/c
– In each volume cell a local equilibration at ~35 fm/c
– System scission at ~55 fm/c
I. N
ovos
el, Z
. Bas
rak
et a
l. , P
hys.
Let
t . B
625
(200
5) 2
6.
Heat & compression
– Maximal compression at ~25 fm/c
– In each volume cell a local equilibration at ~35 fm/c
– System scission at ~55 fm/c
Despite of the establishment of a local equili-brium throughout the compact system the (Eth/A)sys and (Ath/A)proj differ substantially: Global equilibrium is far from being reached!
I. N
ovos
el, Z
. Bas
rak
et a
l. , P
hys.
Let
t . B
625
(200
5) 2
6.
Reaction geometryMaxima of the Eth/A and Acompr/A show as a function of reaction centrality strong geometrical effects.
I. N
ovos
el, Z
. Bas
rak
et a
l. , P
hys.
Let
t . B
625
(200
5) 2
6.
Reaction geometryMaxima of the Eth/A and Acompr/A show as a function of reaction centrality strong geometrical effects.
Observed feature is in the spirit of the participant-spectator picture.
I. N
ovos
el, Z
. Bas
rak
et a
l. , P
hys.
Let
t . B
625
(200
5) 2
6.
Reaction geometryMaxima of the Eth/A and Acompr/A show as a function of reaction centrality strong geometrical effects.
Observed feature is in the spirit of the participant-spectator picture.
An interplay of the NN collisions and the Pauli principle in the overlap zone.
I. N
ovos
el, Z
. Bas
rak
et a
l. , P
hys.
Let
t . B
625
(200
5) 2
6.
Head-on collisionsA targ
(A targ + A proj ) 2Eavail =
c.m. E proj
A proj
A projDependence on available energy
I. N
ovos
el, Z
. Bas
rak
et a
l. , P
hys.
Let
t . B
625
(200
5) 2
6.
Head-on collisions
A universal linear proportionality law proves the eminent role of “hard” NN collisions.
A targ
(A targ + A proj ) 2Eavail =
c.m. E proj
A proj
A projDependence on available energy
I. N
ovos
el, Z
. Bas
rak
et a
l. , P
hys.
Let
t . B
625
(200
5) 2
6.
Dependence of relative sub-systems Eth/A on incident energy for head-on collisionsProjectile ratio =
(Eth/A)proj
Target ratio =
(Eth/A)sys
(Eth/A)targ
(Eth/A)sys
Ratio of thermal energy maxima
I. N
ovos
el, Z
. Bas
rak
et a
l. , P
hys.
Let
t . B
625
(200
5) 2
6.
Dependence of relative sub-systems Eth/A on incident energy for head-on collisionsProjectile ratio =
(Eth/A)proj
Target ratio =
(Eth/A)sys
(Eth/A)targ
(Eth/A)sys
A symmetric system
Ratio of thermal energy maxima
I. N
ovos
el, Z
. Bas
rak
et a
l. , P
hys.
Let
t . B
625
(200
5) 2
6.
Dependence of relative sub-systems Eth/A on incident energy for head-on collisionsProjectile ratio =
(Eth/A)proj
Target ratio =
(Eth/A)sys
(Eth/A)targ
(Eth/A)sys
An asymmetric system
Ratio of thermal energy maxima
I. N
ovos
el, Z
. Bas
rak
et a
l. , P
hys.
Let
t . B
625
(200
5) 2
6.
Dependence of relative sub-systems Eth/A on incident energy for head-on collisionsProjectile ratio =
(Eth/A)proj
Target ratio =
(Eth/A)sys
(Eth/A)targ
(Eth/A)sys
Increasingly asymmetric systems
Ratio of thermal energy maxima
I. N
ovos
el, Z
. Bas
rak
et a
l. , P
hys.
Let
t . B
625
(200
5) 2
6.
Dependence of relative sub-systems Eth/A on incident energy for head-on collisionsProjectile ratio =
(Eth/A)proj
Target ratio =
(Eth/A)sys
(Eth/A)targ
(Eth/A)sys
Increasingly asymmetric systems
Ratio of thermal energy maxima
I. N
ovos
el, Z
. Bas
rak
et a
l. , P
hys.
Let
t . B
625
(200
5) 2
6.
Dependence of relative sub-systems Eth/A on incident energy for head-on collisions
tal change from the fusion-deep inelastic into the BDC – partic.-spect,(fireball)-like behavior.
The reaction geo-metry is important in intermediate E HIC.
The Fermi energy is a transient region where the main reac-tion mechanism un-dergoes a fundamen-
Ratio of thermal energy maxima
I. N
ovos
el, Z
. Bas
rak
et a
l. , P
hys.
Let
t . B
625
(200
5) 2
6.
Conclusions
Mid-rapidity emissionMid-rapidity emission is dominated by the pre-scission dynamicaldynamical contribution
MaximaMaximal heat and pressure generated in a collision closely follow reaction geometryreaction geometry
Head-on collisionsHead-on collisions obey a universal linear linear dependencedependence on the available c.m. energy
Conclusions
Mid-rapidity emissionMid-rapidity emission is dominated by the pre-scission dynamicaldynamical contribution
MaximaMaximal heat and pressure generated in a collision closely follow reaction geometryreaction geometry
Head-on collisionsHead-on collisions obey a universal linear linear dependencedependence on the available c.m. energy
A crucial role of “hard” NN collisions
Conclusions
Mid-rapidity emissionMid-rapidity emission is dominated by the pre-scission dynamicaldynamical contribution
MaximaMaximal heat and pressure generated in a collision closely follow reaction geometryreaction geometry
Head-on collisionsHead-on collisions obey a universal linear linear dependencedependence on the available c.m. energy
A crucial role of “hard” NN collisions
Explains the apparent controversy on the quickly established local equilibrium throughout the compact system and complete lack of global equilibration
OutlookTRacing EQuilibration by ISospin
(the LNS experiment C-71, spokesperson Z. Basrak)
Landau-Vlasov model simulation of the isospin asymmetric 48Ca + 40Ca reaction at 40 MeV/u
N/Z ratio of the quasi-N/Z ratio of the quasi-projectile as a function of bprojectile as a function of b
OutlookTRacing EQuilibration by ISospin
(the LNS experiment C-71, spokesperson Z. Basrak)
Landau-Vlasov model simulation of the isospin asymmetric 48Ca + 40Ca reaction at 40 MeV/u
N/ZN/ZQPQP=1.27 – 1.31=1.27 – 1.31
N/Z ratio of the quasi-N/Z ratio of the quasi-projectile as a function of bprojectile as a function of b
for b < 2 fmfor b < 2 fm
The same system at a similar E in the last month GANIL experiment E-503
(spokesperson A. Chibihi)
Heavy-ion dynamics at Heavy-ion dynamics at the Fermi energythe Fermi energyA theoretical point of A theoretical point of viewview
Heavy-ion dynamics at Heavy-ion dynamics at the Fermi energythe Fermi energyA theoretical point of A theoretical point of viewview
Laboratory for heavy-ion physicsLaboratory for heavy-ion physics Division of Experimental Physics RDivision of Experimental Physics Ruđeruđer
Bošković Bošković Institute, Zagreb, CroatiaInstitute, Zagreb, Croatia
Zoran Basrak
EWON Town Meeting, May 10 –12, 2007, Prague, Czek Republic
EWON
RRuđeruđer Bošković Bošković Institute – SUBATECH Institute – SUBATECH collaborationcollaboration
