Investigation of the freezeout conguration in the 197

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Investigation of the freeze-out configuration in the 197 Au + 197 Au reaction at

Investigation of the freeze-out configuration in the 197 Au + 197 Au reaction at 23 AMe. V Rafał Najman for CHIMERA collaboration M. Smoluchowski Institute of Physics Jagiellonian University The theoretical analysis of properties of superheavy nuclei do not predict any long living nuclei with compact shapes beyond the island of stability (N ~ 184, Z ~ 114).

Search for superheavy nuclei Liquid drop model with shell corrections and Hartree – Fock

Search for superheavy nuclei Liquid drop model with shell corrections and Hartree – Fock – Bogoliubov theory with the Gogny D 1 S force calculations have shown that metastable islands of nuclear bubbles can exist for nuclei in the range A=450 -3000 K. Dietrich, K. Pomorski Phys. Rev. Lett. 80, 37 (1998) J. Decharge et al. Nucl. Phys. A 716, 55 (2003 ) The energy of the toroidal minimum decrease relatively to the potential energy of the spherical configuration with increase of the mass of the system For Z>140 , the global minimum of potential energy corresponds to the toroidal shape M. Warda, Int. J. of Mod. Phys. E 16, 452 (2007)

BUU simulations for central collisions of Au + Au Calculations predict that a threshold

BUU simulations for central collisions of Au + Au Calculations predict that a threshold energy for toroidal freeze-out configuration is at about 23 Me. V / nucleon A. Sochocka et al. , Int. J. Mod. Phys. E 17, 190 (2008)

Results of Im. QMD simulation Prolate spheroid E = 5. 4 – 7. 4

Results of Im. QMD simulation Prolate spheroid E = 5. 4 – 7. 4 AMe. V Flat shape Time evolution of quadrupole moment for 238 U + 238 U Time evolution of 238 U + 238 U at Ecm=3570 Me. V and b=0 fm E = 30 AMe. V Tian et al. , Phys. Rev. C 77, 064603 (2008) 4

Macroscopic droplet collisions Formation the toroidal-shapes configurations can be observed in binary droplet collision

Macroscopic droplet collisions Formation the toroidal-shapes configurations can be observed in binary droplet collision at high velocity V=3. 89 m/s V=9. 1 m/s 5 Phys. Rev. E 80, 036301 2009

CHIMERA – Charged Heavy Ion Mass and Energy Resolving Array 17 rings CHIMERAs advantage:

CHIMERA – Charged Heavy Ion Mass and Energy Resolving Array 17 rings CHIMERAs advantage: • • 687 telescopes on 9 wheels • • 1192 telescopes: Si and Cs. I Low detection threshold 1 Me. V/A Covering almost 94% of 4 Z and A identification

ΔE-E technique

ΔE-E technique

Time of Flight Techinique

Time of Flight Techinique

Global properties of experimental data from 197 Au+197 Au reaction at 23 AMe. V

Global properties of experimental data from 197 Au+197 Au reaction at 23 AMe. V well defined events TLF IVS PLF Fission fragments from PLF decay

Multiplicity distribution for well defined events Nfrag ≥ 5 Nfrag = 3 Nfrag =

Multiplicity distribution for well defined events Nfrag ≥ 5 Nfrag = 3 Nfrag = 4 Nfrag ≥ 5 Zfrag > 2 Zfrag > 9 646000 211000 129000 377000 44000 5000

Shape analysis δ parameter measures the shape of the events in momenta space. Zfrag

Shape analysis δ parameter measures the shape of the events in momenta space. Zfrag > 9

Shape analysis Δ 2 parameter measures the flatness of the events in velocity space.

Shape analysis Δ 2 parameter measures the flatness of the events in velocity space. For toroids it is much smaller than for sphere or bubble. A, B, C, D - plane parameters

Observables distributions Flat events conditions: One can see that for both observables the biggest

Observables distributions Flat events conditions: One can see that for both observables the biggest difference between experimental distribution and model predictions is observed for the Ball 8 V 0, and Bubble 8 V 0 configurations. In contrast to that, the experimental data seem to be more consistent with the simulations assuming toroidal freeze-out configurations.

Location of toroidal events on the ϴplane vs ϴflow plane

Location of toroidal events on the ϴplane vs ϴflow plane

Efficiency factor: Efficiency factor – ratio of number of events fulfilling the selection conditions

Efficiency factor: Efficiency factor – ratio of number of events fulfilling the selection conditions to the total number of events with 5 heavy fragments Flat events conditions: EF is: • Very low for spherical freeze-out configurations in respect to the corresponding values for toroidal configuration • For QMD calculations is strongly dependent on the ϴplane range • For experimental data the value of the EF is about 50% for events located in the reaction plane (ϴplane > 750 ) • Is reduced by factor 2 for events perpendicular to the reaction EF values for experimental data are very close to the model predictions for toroidal configurations. This observation may indicate the formation of toroidal/flat freeze-out configuration created in the Au + Au collisions at 23 Me. V/nucleon.

Other observables In order to get additional evidence to support the hypothesis that toroidal

Other observables In order to get additional evidence to support the hypothesis that toroidal objects are created, the behavior of other observables was investigated: mass standard deviations of fragments, relative angles of fragment pairs, mean velocities of fragments as a function of their mass relative velocities of fragments pairs

Other observables A standard deviation of masses for flat events with 5 fragments

Other observables A standard deviation of masses for flat events with 5 fragments

New observables: Other observables θflow > 20 θplane < 75 θflow > 20 θplane

New observables: Other observables θflow > 20 θplane < 75 θflow > 20 θplane > 75 θflow < 20 θplane < 75 θflow < 20 θplane > 75 Inside reaction plane Vij is mean value of relative velocities for flat events with 5 fragments Outside reaction plane Inside reaction plane Outside reaction plane region where observation of toroidal freeze-out configuration is expected region dominated noncentral collisions For Vij distributions the mean values for class of events located outside the reaction plane are smaller in comparison to the case of events located in the reaction plane. This observation may be used as an indication that for events located outside the reaction plane freeze-out configuration is more extended in comparison with that for events located inside reaction plane.

Road Map 1. Search for toroidal freeze-out configurations in events with smaller number of

Road Map 1. Search for toroidal freeze-out configurations in events with smaller number of fragments (3 and 4) 2. Isotopic identification of light fragments ( 3 ≤ Z ≤ 9 ) 3. Investigation of isotopic composition of IVS

Summary and outlook The experimental data for well defined events have been shown. The

Summary and outlook The experimental data for well defined events have been shown. The experimental data are compared with ETNA and QMD model predictions. Efficiency factor is used as indication of formation of exotic freeze-out configuration. Comparison between experimental data and model predictions may indicate the formation of flat/toroidal nuclear system. Distribution of vij indicates that toroidal freeze-out configuration may be created outside reaction plane Additional analysis of experimental data

Breakup Collaboration F. Amorini 1, 2, L. Auditore 3, A. Bubak 4, T. Cap

Breakup Collaboration F. Amorini 1, 2, L. Auditore 3, A. Bubak 4, T. Cap 5, G. Cardella 6, E. De Filippo 6, E. Geraci 2, 6, L. Grassi 2, 6, A. Grzeszczuk 4, E. La Guidara 7, J. Han 1, D. loria 3, S. Kowalski 4, T. Kozik 8, G. Lanzalone 1, 9, I. Lombardo 2, 9, Z. Majka 8, R. Najman 8, N. G. Nicolis 10, A. Pagano 6, E. Piasecki 11, S. Pirrone 6, R. Płaneta 8, G. Politi 2, 6, F. Rizzo 1, 2, P. Russotto 1, 2, K. Siwek-Wilczyńska 5, I. Skwira-Chalot 5, A. Sochocka 12, A. Trifirò 3, M. Trimarchi 3, J. Wilczyński 13, G. Verde 6, W. Zipper 4 1) INFN, Laboratori Nazionali del Sud, Catania, Italy 2) Dipartimento di Fisica e Astronomia Universitá di Catania, Italy 3) Dipartimento di Fisica Universitá di Messina and INFN Gruppo Collegato di Messina, Italy 4) Institute of Physics, University of Silesia, Katowice, Poland 5) Faculty of Physics, University of Warsaw, Poland 6)INFN, Sezione di Catania, Italy 7)Centro Siciliano di Fisica Nucleare e Struttura della materia 8) M. Smoluchowski Institute of Physics, Jagiellonian University, Kraków, Poland 9)Università Kore, Enna, Italy 10)Department of Physics, The University of Ioannina, Greece 11) Heavy Ion. Laboratory, University of Warsaw, Poland 12) Department of Physics, Astronomy and Applied Informatics, Jagiellonian University, Kraków, Poland 13) A. Sołtan. Institute for Nuclear Studies, Świerk, Poland

Reconstruction results

Reconstruction results

Estimation of collision centrality One can see on this plot that noncentral events are

Estimation of collision centrality One can see on this plot that noncentral events are located at small θflow angles (> 20 degree) and big θplane angles (< 75 degree). As an impact parameter estimator for experimental data we used total transverse momentum

CHIMERA – Charged Heavy Ion Mass and Energy Resolving Array

CHIMERA – Charged Heavy Ion Mass and Energy Resolving Array

To. F Techinique E- particle energy [Me. V] calculated from: E=a. L· Channeldesilpg +

To. F Techinique E- particle energy [Me. V] calculated from: E=a. L· Channeldesilpg + b. L m- ion mass [u] R – distance from target to detector [cm] t 0 – time offset calculated for each detector [ns] α= 3·T / d T- cyclotron period [ns] d- distance between two beam bursts [channels] For calibration data the following 8 -parametres function is fitted:

To. F Techinique

To. F Techinique

QMD + GEMINI Nukleony są przedstawione w formie paczek falowych o stałej szerokości w

QMD + GEMINI Nukleony są przedstawione w formie paczek falowych o stałej szerokości w czasie układ ewoluuje zgodnie z równaniem Hamiltona. CM b) 0 Klasteryzacja 300 Czas [ fm/c ] QMD – model dynamiczny detektor LAB Rozpad gorących frgmentów i przyśpiesznie w polu kulombowskim Zimne fragmenty Kod GEMINI Czas [ fm/c ]

ETNA – Expecting Toroidal Nuclear Agglomeration + GEMINI kod Opisuje rozpad obiektu tworzonego w

ETNA – Expecting Toroidal Nuclear Agglomeration + GEMINI kod Opisuje rozpad obiektu tworzonego w fazie wymrażania. Obiekt taki tworzy się po emisji nukleonów przedrównowagowych z systemu złożonego, który powstaje w wyniku połączenie się jądra wiązki z jądrem tarczy. ACN = AT + AP ZCN = ZT + ZP -minus nukleony emitowane w początkowej fazie (preequilibrium) reakcji Losowanie fragmentów: • Rozkład Gaussa < Zfrag > = Ztot / N N =5 – liczba fragmentow Wszystkie fragmenty są umieszczane w konfiguracji “wymrożenia” w kształcie kuli, bańki i toroidu warunek przekrywania: Rij > Ri + Rj + 2 fm Uwzględnienie niecentralnych kolizji dla zadanego parametru zderzenia b Eava = ECM + Q – ECOULOMB - dostępna energia Podział dostępnej energii: Eava= E* + E th = Na. T 2 +3/2 k(N-1)T ; zakladając równą temperaturę, N – liczba fragmentów Dynamiczny kod GEMINI: rozpad wzbudzonych fragmentów przyśpieszanie w polu kulombowskim Detekcja cząstek w detektorze CHIMERA , numer detektora rand , rand Próg energetyczny Ethr= 1 Me. V/A Z FWHM = 1 ch. u. A=2. 08* Z ( przewidywania kodu GEMINI )

Definition of sphericity and coplanarity From the cartesian components of fragment Z 5 momenta

Definition of sphericity and coplanarity From the cartesian components of fragment Z 5 momenta in the centre of mass may construct the tensor where p(n) i is the i-th Cartesian momentum component of the n-th particle, and is the n-th fragment momentum vector. The diagonalization of the momentum tensor gives the eigenvalues: ti, (t 1 < t 2 < t 3).