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Acknowledgements. Exochim & Farcos collaboration : - PowerPoint PPT Presentation
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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