Transcript Presentazione di PowerPoint - Dipartimento di Fisica

HIC
B
large
nucleon
momenta
Isospin-Dynamics
Dynamics
inHeavy
HeavyIon
Ion
Collisions:
Isospin
in
Collisions
probing
different
B :regions
IsospinEOSDynamics
in
Heavy
Ion
Collisions
:
-sensitive observables
EOS
EOS-sensitive
observables
 Mean field
EOSEOS-sensitive observables
- large
momenta
Transportnucleon
properties
 Effective masses
HIC
HIC
 Cross
sections
Mean
field
probing - different B regions
probing- -large
different
Bmomenta
regions
nucleon
- large nucleon momenta

 Mean field
 Mean field
 Effective masses
 Effective masses
 Effective masses
 Cross sections
 Cross sections
 Cross sections
Transport properties
Transport properties
Transport properties
Isospin distillation
 Isospin diffusion
 Neck
fragmentation
 Isospin distillation
Isospindiffusion
distillation
 Isoscaling
Isospin
Fermi Energies

Isospin
diffusion
 Neck fragmentation
symmetric
 Lane
Potential, E-slope
 Neck fragmentation

1
neutron
symmetric
1
neutron
neutron
1
Sly4
symmetric
1
Sly4
Sly4
a4
neutron
 Isoscaling
Isoscaling
Lane
Potential,
1

1
E-slope
Lane
Potential,
E-slope

Isospin distillation
 Isospin diffusion
 Neck fragmentation
 Isoscaling
 Lane Potential, E-slope
1
a4
a4
symmetric
Sly4
1
 Pre-equilibrium dipole
Instability of binary systems
F = e - Ts
Free energy density
d
3
Instability Condition
r F  0
 P    p 
  0

 
  T , y  y T , P
 1  F0pp  2  1  F0nn  2  F0np F0pn 

  
pn  0
  

 N  p  N  n N

p 
n 


 p Nn 
X u2+Y
v2 <
0
X<0 isoscalar-like
Y<0 isovector-like
u= cosb p+senb n
v= cosb p-senb n
X Y=
tg 2 b 
Mechanical
n n Chemical

effect
 p  p
N n F0pn  N p F0np
N p (1  F0nn ) - N n (1  F0pp )
N p2 N n2  P    p 
  0

 
2
(1 - y )    T , y  y T , P
Chemical
n = p
b  45
V. Baran et al., PRL86 (2001) 4492
Isospin Distillation Mechanism:
“direction” of the spinodal unstable mode
~
E SYM

!
y = proton fraction =Z/A
124Sn+124Sn
50AMeV, central
STOCHASTIC
MEAN-FIELD
Freeze-out
configuration
124Sn+ 124Sn
50 AMeV: average asymmetry
time evolution
I(t)
freeze-out
IMF
gas
Central
b=0.15 bmax
liquid
Asy-soft
I(t)
600 SMF events
Semi-central
b=0.5 bmax
V. Baran et al., NPA(2002)
124Sn+ 124Sn
50 AMeV: average asymmetry
time evolution
freeze-out
IMF
gas
Central
b=0.15 bmax
I(t)
liquid
Asy-stiff
Semi-central
b=0.5 bmax
I(t)
600 SMF events
V. Baran et al., NPA(2002)
Dynamical Isoscaling
124
Sn
light ion yield
112
Sn
primary
50 AMeV
Z=1
(central coll.)
Z=7
final
 ( -  ) 2A

Y ( N , Z )  f ( A) exp 2
s


2 1 - (Zº/ Aº)²
N -2 Z

α
= 4ln[R(Zº/ Aº)²
]/σ²






21
2
1
s2
 A 
not very sensitive to Esym ?
124Sn
Carbon isotopes (primary)
T.X.Liu et al.
PRC 2004
Asy-stiff
Asy-soft
A