Heavy-ion dynamics at the Fermi energy A theoretical point of view Heavy-ion dynamics at the Fermi energy A theoretical point of view Laboratory for heavy-ion.

Heavy-ion dynamics at the Fermi energy A theoretical point of view Heavy-ion dynamics at the Fermi energy A theoretical point of view Laboratory for heavy-ion physics Division of Experimental Physics Ruđer Bošković Institute, Zagreb, Croatia Zoran Basrak EWON Town Meeting, May 10 –12, 2007, Prague, Czek Republic Ruđer Bošković Institute – SUBATECH collaboration

 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  TOT   FUS   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:  TOT   FUS   B.P.  TOT   FUS Hot nuclei !!!

Binary Dissipative Collisions – BDC opens around the Fermi energy Irrespectively of - event centrality - system size - system asymmetry V.Metivier et al. (INDRA Collaboration), Nucl. Phys. A672 (2000) 357.  TOT   FUS

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. Peter et al., Nucl. Phys. A593 (1995) 95.  Reconstructed primary QP mass approxim.. equal to the projectile mass QP emission in BDC’s

J. Peter et al., Nucl. Phys. A593 (1995) 95.  Reconstructed primary QP mass approxim.. equal to the projectile mass  Thus obtained primary QP extremely hot Y.-G. Ma et al., Phys. Lett. B390 (1997) 41. Ar (95 MeV/u) Ni

QP emission in BDC’s J. Peter et al., Nucl. Phys. A593 (1995) 95.  Reconstructed primary QP mass approxim.. equal to the projectile mass  Thus obtained primary QP extremely hot Y.-G. Ma et al., Phys. Lett. B390 (1997) 41. Ar (95 MeV/u) Ni

Dynamical emission component Ph. Eudes, Z. Basrak and F. Sebille, Phys. Rev. C56 (1997) 2003. Landau-Vlasov model simulation Ar ( 65 MeV / u ) Al

F. Haddad et al., Phys. Rev. C60 (1999) 031603. Z dynam emiss Z targ + Z proj = 100 Dynamical emission component D em (%) = System Incident energy (MeV/u) 40 Ar+ 27 Al41, 65 40 Ar+ 107 Ag50, 75, 100 107 Ag+ 40 Ar50 36 Ar+ 58 Ni52, 74, 95 12O Xe+ 129 Sn50, 75, 100

Statistical emission component Landau-Vlasov model simulation The geniune primary QP emission Ar ( 65 MeV / u ) Al

Statistical emission component Ph. Eudes and Z. Basrak, Eur. Phys. J. A 9 (2000) 207. Landau-Vlasov model simulation Ar ( 65 MeV / u ) Al The 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. Dore et al. (INDRA Collaboration), Phys. Lett. B491 (2000) 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 local equilibration Configuration space Impulse space pre-scissionpost-scission

Mid-rapidity emission in BDC’s ≈ pre-scission emissionMid-rapidity emission max. compression local equilibration Configuration space Impulse space pre-scissionpost-scission

Early energy transformation E tot = E collect + E intrin E intrin = E excit + E potent Decompression followed by abundant emission and fast system cooling.

Early energy transformation E tot = E collect + E intrin E intrin = E excit + E potent System Incident energy (MeV/u) b/b max 40 Ar+ 27 Al41, 650, … (0.1) … 1 36 Ar+ 58 Ni52, 74, 950, … (0.2) … 1 40 Ar+ 107 Ag50, 75, 1000, … (0.1) … 1 12O Xe+ 129 Sn50, 75, 1000, … (0.2) … 1 40 Ar+ 107 Ag20, 30, 40, 450 40 Ar+ 197 Au50, 75, 1000 Decompression followed by abundant emission and fast system cooling. - A sys = ~70 - ~250 nucl - A proj :A targ = 1:1 – 1:5 - b rel = 0, … (0.1) … 1 I. Novosel, Z. Basrak et al., Phys. Lett. B625 (2005) 26.

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. Novosel, Z. Basrak et al., Phys. Lett. B625 (2005) 26.

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 equilibrium throughout the compact system the (E th /A) sys and (A th /A) proj differ substantially: Global equilibrium is far from being reached! I. Novosel, Z. Basrak et al., Phys. Lett. B625 (2005) 26.

Reaction geometry Maxima of the E th /A and A compr /A show as a function of reaction centrality strong geometrical effects. I. Novosel, Z. Basrak et al., Phys. Lett. B625 (2005) 26.

Reaction geometry Maxima of the E th /A and A compr /A show as a function of reaction centrality strong geometrical effects. Observed feature is in the spirit of the participant- spectator picture. I. Novosel, Z. Basrak et al., Phys. Lett. B625 (2005) 26.

Reaction geometry Maxima of the E th /A and A compr /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. Novosel, Z. Basrak et al., Phys. Lett. B625 (2005) 26.

Head-on collisions A targ (A targ + A proj ) 2 E avail = c.m. E proj A proj Dependence on available energy I. Novosel, Z. Basrak et al., Phys. Lett. B625 (2005) 26.

Head-on collisions A universal linear proportionality law proves the eminent role of “hard” NN collisions. A targ (A targ + A proj ) 2 E avail = c.m. E proj A proj Dependence on available energy I. Novosel, Z. Basrak et al., Phys. Lett. B625 (2005) 26.

Dependence of relative sub-systems E th /A on incident energy for head-on collisions Projectile ratio = (E th /A) proj Target ratio = (E th /A) sys (E th /A) targ (E th /A) sys Ratio of thermal energy maxima I. Novosel, Z. Basrak et al., Phys. Lett. B625 (2005) 26.

Dependence of relative sub-systems E th /A on incident energy for head-on collisions Projectile ratio = (E th /A) proj Target ratio = (E th /A) sys (E th /A) targ (E th /A) sys A symmetric system Ratio of thermal energy maxima I. Novosel, Z. Basrak et al., Phys. Lett. B625 (2005) 26.

Dependence of relative sub-systems E th /A on incident energy for head-on collisions Projectile ratio = (E th /A) proj Target ratio = (E th /A) sys (E th /A) targ (E th /A) sys An asymmetric system Ratio of thermal energy maxima I. Novosel, Z. Basrak et al., Phys. Lett. B625 (2005) 26.

Dependence of relative sub-systems E th /A on incident energy for head-on collisions Projectile ratio = (E th /A) proj Target ratio = (E th /A) sys (E th /A) targ (E th /A) sys Increasingly asymmetric systems Ratio of thermal energy maxima I. Novosel, Z. Basrak et al., Phys. Lett. B625 (2005) 26.

Dependence of relative sub-systems E th /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 geometry is important in intermediate E HIC.  The Fermi energy is a transient region where the main reaction mechanism un- dergoes a fundamen- Ratio of thermal energy maxima I. Novosel, Z. Basrak et al., Phys. Lett. B625 (2005) 26.

Conclusions

A crucial role of “hard” NN collisions

Conclusions 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

Outlook TRacing EQuilibration by ISospin (the LNS experiment C-71, spokesperson Z. Basrak) Landau-Vlasov model simulation of the isospin asymmetric 48 Ca + 40 Ca reaction at 40 MeV/u N/Z ratio of the quasi- projectile as a function of b N/Z ratio of the quasi- projectile as a function of b

Outlook TRacing EQuilibration by ISospin (the LNS experiment C-71, spokesperson Z. Basrak) Landau-Vlasov model simulation of the isospin asymmetric 48 Ca + 40 Ca reaction at 40 MeV/u N/Z QP =1.27 – 1.31 N/Z ratio of the quasi- projectile as a function of b N/Z ratio of the quasi- projectile as a function of b for 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 the Fermi energy A theoretical point of view Heavy-ion dynamics at the Fermi energy A theoretical point of view Laboratory for heavy-ion physics Division of Experimental Physics Ruđer Bošković Institute, Zagreb, Croatia Zoran Basrak EWON Town Meeting, May 10 –12, 2007, Prague, Czek Republic Ruđer Bošković Institute – SUBATECH collaboration

Heavy-ion dynamics at the Fermi energy A theoretical point of view Heavy-ion dynamics at the Fermi energy A theoretical point of view Laboratory for heavy-ion.

Similar presentations

Presentation on theme: "Heavy-ion dynamics at the Fermi energy A theoretical point of view Heavy-ion dynamics at the Fermi energy A theoretical point of view Laboratory for heavy-ion."— Presentation transcript:

Similar presentations

About project

Feedback

Log in

Auth with social network:

Heavy-ion dynamics at the Fermi energy A theoretical point of view Heavy-ion dynamics at the Fermi energy A theoretical point of view Laboratory for heavy-ion.

Similar presentations

Presentation on theme: "Heavy-ion dynamics at the Fermi energy A theoretical point of view Heavy-ion dynamics at the Fermi energy A theoretical point of view Laboratory for heavy-ion."— Presentation transcript:

Similar presentations

About project

Feedback