Nuclear physics activity in Institute for Nuclear Research and Nuclear Energy, Sofia Ch....

Nuclear physics activity inNuclear physics activity inInstitute for Nuclear Institute for Nuclear

Research and Nuclear Research and Nuclear Energy,Energy,

SofiaSofia

Ch. Protochristov, Ch. StoyanovCh. Protochristov, Ch. Stoyanov

Historical remarksHistorical remarks

Prof. Dr. Elisabeth Prof. Dr. Elisabeth Kara – Michailova Kara – Michailova

(1897-1968)(1897-1968)

• obtained Ph.D at the Vienna University, Austria in 1923• Nucl. Spectroscopy research at the Radium Institute Vienna• invited by Rutherford in Cavendish Laboratory in Cambridge, important contributions in dosimetry• the first women, to become professor at the Sofia University• head of the newly established chair of Atomic Physics• introduced the photo emulsion method in cosmic-ray investigations in Bulgaria

Prof. Dr. sc. Zhelio Zhelev (1923-1988)Prof. Dr. sc. Zhelio Zhelev (1923-1988)

investigations of natural radioactivity in Bulgariainvestigations of natural radioactivity in Bulgaria postgraduated in Leningrad (St.Peterburg), Russiapostgraduated in Leningrad (St.Peterburg), Russia experimental investigations of short-lived isotopesexperimental investigations of short-lived isotopes headed the Department of Nuclear Spectroscopyheaded the Department of Nuclear Spectroscopy In 1969 he founded the International School on In 1969 he founded the International School on Nuclear Physics, Neutron Physics and Nuclear EnergyNuclear Physics, Neutron Physics and Nuclear Energy

Acad. Wenzeslav Andrejtscheff Acad. Wenzeslav Andrejtscheff (1941-2001)(1941-2001)

studied at the Technical studied at the Technical University Dresden University Dresden developed the Generalized developed the Generalized Centroid Shift Method (GCSM)Centroid Shift Method (GCSM) head of the Department of Nuclear Spectroscopyhead of the Department of Nuclear Spectroscopy professor in the University of New Brunswick, USAprofessor in the University of New Brunswick, USA member of the Bulgarian Academy of Sciencesmember of the Bulgarian Academy of Sciences

Head of the group JRSI (Nuclear & Roentgen Head of the group JRSI (Nuclear & Roentgen Research) in the Department of Nuclear Research) in the Department of Nuclear Spectroscopy(1966-1996);Spectroscopy(1966-1996);

Professor in the Physics Department of Sofia Professor in the Physics Department of Sofia (1964-1996);(1964-1996);

Member of the Bulgarian Academy of Member of the Bulgarian Academy of Sciences (1995);Sciences (1995);

Vice-director of the Laboratory of Nuclear Vice-director of the Laboratory of Nuclear Reactions, JINR - Dubna (1982-1986).Reactions, JINR - Dubna (1982-1986).

He combined scientific investigationsHe combined scientific investigations in theoretical nuclear physics andin theoretical nuclear physics and experimental nuclear spectroscopy. experimental nuclear spectroscopy. In the seventies some 30% of the data ofIn the seventies some 30% of the data of lifetimes of high-spin states in deformed lifetimes of high-spin states in deformed rare-earth nuclei have been generated by therare-earth nuclei have been generated by the group headed by acad. E. Nadjakov in closegroup headed by acad. E. Nadjakov in close collaboration with JINR-Dubna. collaboration with JINR-Dubna. Often citatedOften citated is his last work no nuclear charge radii.is his last work no nuclear charge radii.

Acad. Emil G.NadjakovAcad. Emil G.Nadjakov (1929-1996)(1929-1996)

Joint Institute for Nuclear Research Joint Institute for Nuclear Research Dubna Dubna

Present statusPresent statusThe activity in the nuclear physics in INRNE is concentrated The activity in the nuclear physics in INRNE is concentrated

mainly in the Department of Nuclear Physics. There are 4 laboratories mainly in the Department of Nuclear Physics. There are 4 laboratories in the Department:in the Department:

Laboratory of Nuclear SpectroscopyLaboratory of Nuclear Spectroscopy Laboratory of Nuclear ReactionLaboratory of Nuclear Reaction Laboratory of Positron SpectroscopyLaboratory of Positron Spectroscopy Laboratory of Semi-conductor DetectorsLaboratory of Semi-conductor Detectors Laboratory of Theoretical Nuclear Physics does not belong to Laboratory of Theoretical Nuclear Physics does not belong to

Department of Nuclear Physics but the activity of this Lab is mainly Department of Nuclear Physics but the activity of this Lab is mainly devoted to study the structure of atomic nuclei.devoted to study the structure of atomic nuclei.

Altogether, INRNE is the leading and complex center for research and application Altogether, INRNE is the leading and complex center for research and application of nuclear science in Bulgaria. More that 40 researchers are included in the activity of nuclear science in Bulgaria. More that 40 researchers are included in the activity connected with nuclear physics. Around half of them are less than 40 years oldconnected with nuclear physics. Around half of them are less than 40 years old . .

Experimental physics:

The basic facilities like accelerators are not available and the research reactor is under reconstruction. Because of that the main part of experimental work is done in collaboration with European research centers like CERN, GANIL, INFN, LNL-Legnaro, GSI-Darmstadt, IreS Strasbourg, JINR-Dubna etc.

The members of the Lab applied the method of high-resolution gamma-The members of the Lab applied the method of high-resolution gamma-spectroscopy to study the environmental problems. The systematical spectroscopy to study the environmental problems. The systematical investigations of the environmental radioactivity in the Bansko – Razlog investigations of the environmental radioactivity in the Bansko – Razlog region, carried out during the recent years, have been enlarged with region, carried out during the recent years, have been enlarged with investigations of Cs-137 concentration in soil, performed here for the first investigations of Cs-137 concentration in soil, performed here for the first time. A total area of about 40 km2 has been investigated, by means of high-time. A total area of about 40 km2 has been investigated, by means of high-resolution gamma-ray spectroscopy, thereby the radio-nuclide content of the resolution gamma-ray spectroscopy, thereby the radio-nuclide content of the soil samples has been determined. The results gave us the opportunity to soil samples has been determined. The results gave us the opportunity to assess the total Cs-137 fallout in the region. The measured concentrations assess the total Cs-137 fallout in the region. The measured concentrations are compared with previous data obtained for other regions in Bulgaria. The are compared with previous data obtained for other regions in Bulgaria. The Cs-137 fallout following the Chernobyl accident has been estimated and Cs-137 fallout following the Chernobyl accident has been estimated and compared with the results obtained in other countries. The additional dose compared with the results obtained in other countries. The additional dose rate caused by this fallout has been estimated. `rate caused by this fallout has been estimated. `

Laboratory of Nuclear SpectroscopyLaboratory of Nuclear Spectroscopy

During the last years the activity of Laboratory During the last years the activity of Laboratory of Nuclear Spectroscopy was concentrated on of Nuclear Spectroscopy was concentrated on the traditional for the Lab fields – theoretical the traditional for the Lab fields – theoretical and experimental nuclear physics and some and experimental nuclear physics and some applications.applications.

The new direction of the experimental activity of the Lab is connected with The new direction of the experimental activity of the Lab is connected with nuclear waist transmutation problems. Spalation neutrons, produced by nuclear waist transmutation problems. Spalation neutrons, produced by bombardment of heavy targets such as Pb, Pb-Bi, Hg etc. are used for bombardment of heavy targets such as Pb, Pb-Bi, Hg etc. are used for transmutation of long-lived radioactive waste. The special design of the transmutation of long-lived radioactive waste. The special design of the transmutation facilities depends on the neutron spectra and on details of transmutation facilities depends on the neutron spectra and on details of nuclear reactions induced by neutrons, which can be studied by high-nuclear reactions induced by neutrons, which can be studied by high-resolution gamma-ray spectroscopy. Therefore spallation spectra from resolution gamma-ray spectroscopy. Therefore spallation spectra from massive lead targets (20 cm), irradiated with 1 GeV protons from the massive lead targets (20 cm), irradiated with 1 GeV protons from the NUCLOTRON accelerator, have been investigated. The gamma-ray spectra NUCLOTRON accelerator, have been investigated. The gamma-ray spectra emitted by decaying of residual nuclei produced by spallation neutrons in emitted by decaying of residual nuclei produced by spallation neutrons in (n,xn), (n,xnyp), (n,p) and (n,n) reactions with activation threshold detectors (n,xn), (n,xnyp), (n,p) and (n,n) reactions with activation threshold detectors 209-215 Bi were measured in the Laboratory of Nuclear Problems (LNP), 209-215 Bi were measured in the Laboratory of Nuclear Problems (LNP), JINR Dubna. The corresponding gamma-ray spectra have been analyzed JINR Dubna. The corresponding gamma-ray spectra have been analyzed with specialized software and the cross sections for the different reactions with specialized software and the cross sections for the different reactions have been obtained. have been obtained.

The experimental techniques employed include the Recoil distanceDoppler-shift (RDDS) method, the Doppler-shift attenuation method (DSAM)and the delayed-coincidence method. These techniques cover a rangefrom e.g. hundred nanoseconds (which is not an upper limit) down tofew fs. This range nearly exhausts most of the level lifetimes of interest for Nuclear Spectroscopy.

Most important results:

• For the first time it was possible to take into account precisely the time-velocity correlations in Doppler-shift coincidence measurements when the gate is set on a fraction of the line-shape.

•For the first time taking into account of the finite stopping time of the recoils in the stopper in RDDS measurements led to a correction for the lifetimes typically from 20% to 70%, for lifetime values of about 1 ps and 0.3 ps, respectively.

In this experimental field, since more than 20 years we have a collaboration with the Institute fuer Kernphysik of the University of Cologne, namely with the group of Prof. J. Jolie, Prof. P. von Brentano and Dr. A. Dewald. This collaboration resulted so far in more than 40 publications in refereed journals like Phys. Rev. C and Nucl. Phys. A.

Recently, some new topics are the focus of our collaboration asa possible new region of X(5) nuclei around mass A=180, the application of the theoretical supersymmetry scheme to 195Pt and the isospin purity in Z=N nuclei (e.g. Ref.[20]) as well as experimental developments with the aim to perform RDDS measurements with beams of relativistic ions in exotic nuclei.

The knowledge of the lifetimes of excited nuclear states allows thederivation of absolute transition probabilities and of absolute values of reduced transition matrix elements. These experimental quantities represent a stringent test information for nuclear models because they are very sensitive to the wave functions of the initial and final states. Therefore the determination of lifetimes is of importance for the understanding of nuclear structure.

Lifetime Measurements in Nuclear Lifetime Measurements in Nuclear Spectroscopy Spectroscopy

•collaboration: Laboratori Nazionali di Legnaro, Italy

•Publications related to this subject:1. D. Tonev, G. de Angelis, P. Petkov, A. Dewald, S. Brant,S. Frauendorf, D. L. Balabanski, P. Pejovic, D. Bazzacco, P. Bednarczyk, F. Camera, A. Fitzler, A. Gadea, S. Lenzi, S. Lunardi, N. Marginean, O. M\"oller, D. R. Napoli, A. Paleni, C. M. Petrache, G. Prete, K. O. Zell, Y. H. Zhang, Jing-ye Zhang, Q. Zhong, and D. Curien, "Transition probabilities in 134Pr: A test for chirality in nuclear systems", Phys. Rev. Lett. 96 (2006) 052501.

2. D. Tonev, G. de Angelis, P. Petkov, A. Dewald, A. Gadea, P. Pejovic, D. L. Balabanski, P. Bednarczyk, F. Camera, A. Fitzler, O. Moller, N. Marginean, A. Paleni, C. Petrache, K. O. Zell, Y. H. Zhang,"Check for chirality in real nuclei",Eur. Phys. J. A 25 Suppl. 1, (2005) 447

Investigation of chiral symmetry in Investigation of chiral symmetry in nuclear systems. nuclear systems.

Since few years, we have also a fruitful collaboration with the group of G. de Angelis from the Laboratori Nazionali di Legnaro, Italy, where operates the multidetector array GASP. The main topic studied within this collaboration is chirality in nuclear physics, concentrating on RDDS and DSAM data for 134Pr, which was considered to be the best example where the broken symmetry is realized. It was found that in this nucleus chirality exists only in a dynamical context.

•collaborations:

University of Cologne

•Publications related to this subject:• D. Tonev, A. Dewald, T. Klug, P. Petkov, J. Jolie, A. Fitzler, O. Moller, S. Heinze, P. von Brentano and R. F. Casten,"Transition probabilities in 154Gd: Evidence for X(5) critical point symmetry", Phys. Rev. C 69 (2004) 034334.• A. Dewald, O. Moller, D. Tonev, A. Fitzler, B. Saha, K. Jessen, S. Heinze, A. Linnemann, J. Jolie, K. O. Zell, P. von Brentano,P.Petkov, R. F. Casten, M. Caprio, J. R. Cooper, R. Krucken, V. Zamfir, D. Bazzacco, S. Lunardi, C. Rossi-Alvarez, F. Brandolini, C. Ur, G. De Angelis, D. R. Napoli, E. Farnea, N. Marginean, T. Martinez, M. Axiotis, "Shape changes and test of the critical point symmetry X(5) in N=90 nuclei",European Physical Journal A 20 (2004) 173.• O. Mőller, A. Dewald, P. Petkov, B. Saha, A. Fitzler, K. Jessen,D. Tonev, T. Klug, S. Heinze, J. Jolie, P. von Brentano, D. Bazzacco,C. Ur, E. Farnea, M. Axiotis, S. Lunardi, G. de Angelis, D.R. Napoli,N. Marginean, T. Martinez, M. Caprio, and R.F. Casten, "Electromagnetic transition strengths in 156Dy", Phys. Rev. C 74 (2006) 024313.

Investigation of critical points of Investigation of critical points of shape/phase transitions in nuclei.shape/phase transitions in nuclei.

Lifetime measurements in 154Gd were performed by means of the RecoilDistance Doppler-shift method. Excited states of 154Gd were populatedvia Coulomb excitation with a 32S beam at 110 MeV delivered by the FNtandem accelerator of the University of Cologne. The data show that154Gd is one of the good examples of the realization of the X(5) dynamicalsymmetry. In addition, the experimental data are compared to fits in theframework of the IBA and the General Collective Model (GCM). A comparisonof the model predictions and experimental data are shown in Fig. 2.

The activity of Laboratory of The activity of Laboratory of Nuclear SpectroscopyNuclear Spectroscopy

Several theoretical results have been obtained:Several theoretical results have been obtained:

MICROSCOPIC DESCRIPTION OF THE STRUCTURE OF EXCITED STATES

Dipole excitations

Dipole excitationsDipole excitations Dipole excitations below the neutron threshold in neutron-rich Dipole excitations below the neutron threshold in neutron-rich

Sn isotopes are studied theoretically in the Quasiparticle-Sn isotopes are studied theoretically in the Quasiparticle-Phonon Model with Hartree-Fock-Bogoliubov single-particle Phonon Model with Hartree-Fock-Bogoliubov single-particle input. Of special interest are the low-lying two-phonon 1-input. Of special interest are the low-lying two-phonon 1-states and Pygmy Dipole Resonance (PDR). The evolution of states and Pygmy Dipole Resonance (PDR). The evolution of low-energy dipole excitations with neutron excess are low-energy dipole excitations with neutron excess are investigated over the Sn isotopic chain including the investigated over the Sn isotopic chain including the experimentally unknown region close to 132 Sn. A experimentally unknown region close to 132 Sn. A dependence of the PDR strengths and centroid energies on the dependence of the PDR strengths and centroid energies on the neutron skin thickness is found. Despite significant multi-neutron skin thickness is found. Despite significant multi-phonon contributions to mean energies and transition phonon contributions to mean energies and transition strengths, the PDR states retain their one-phonon character. strengths, the PDR states retain their one-phonon character. The fragmentation pattern is reduced with increasing neutron The fragmentation pattern is reduced with increasing neutron excess towards the N=82 shell closure which will be of excess towards the N=82 shell closure which will be of advantage for the future experimental work.advantage for the future experimental work.

COLLABORATIONS•Institut für Theoretische Physik, Universität Giessen, Germany•Institute de Physique Theorique, Univeriste Paris-Sud XI, France•Bogolyubov Laboratory of Theoretical Physics , Dubna, Russia

SOME RECENT PUBLICATIONS:•N. Tsoneva, H. Lenske, Ch. Stoyanov. Pygmy Dipole Resonances as a Manifestation of the Structure of

the Neutron Rich Nuclei . Nucl. Phys. A731(2004) pp. 273 - 280•N. Tsoneva, H. Lenske, Ch. Stoyanov. Probing the nuclear skin by low-energy dipole modes. Phys. Lett. B586 (2004) pp. 213 - 218




Dipole excitations

High-lying states

High-lying statesHigh-lying states Highly excited single-particle states in nuclei are coupled with Highly excited single-particle states in nuclei are coupled with

the excitations of more complex character, first of all with the excitations of more complex character, first of all with collective phononlike modes of the core. In the framework of collective phononlike modes of the core. In the framework of the quasiparticle-phonon model, the structure of resulting the quasiparticle-phonon model, the structure of resulting complex configurations is considered, using 1kcomplex configurations is considered, using 1k17/217/2 orbital in orbital in 209209 Pb as an example. Although, on the level of one- and two-Pb as an example. Although, on the level of one- and two-phonon admixtures, the fully chaotic Gaussian orthogonal phonon admixtures, the fully chaotic Gaussian orthogonal ensemble regime is not reach, the eigenstates of the model ensemble regime is not reach, the eigenstates of the model carry a significant degree of complexity that can be quantified carry a significant degree of complexity that can be quantified with the aid of correlated invariant entropy. Artificially with the aid of correlated invariant entropy. Artificially enhanced particle-core coulping, the system undergoes the enhanced particle-core coulping, the system undergoes the doubling phase transition with the quasiparticle strength doubling phase transition with the quasiparticle strength concemtrated in two repelling peaks. This phase transition is concemtrated in two repelling peaks. This phase transition is clearly detected by correlational entropy clearly detected by correlational entropy

COLLABORATIONSDepartment of Physics and Astronomy, Michigan State University, National Superconducting Cyclotron Laboratory and East Lansing, Michigan

SOME RECENT PUBLICATIONS:Ch. Stoyanov, V. Zelevinsky. High-lying single-particle modes, chaos, correlational entropy, and doubling phase transition. Phys. Rev. C v. 70 (2004) p. 014302, 7p.




Dipole excitations

High-lying states

Mixed symmetry states

Mixed symmetry statesMixed symmetry states

Within the microscopic multiphonon approach the Within the microscopic multiphonon approach the proton-neutron symmetry symmetry and phonon proton-neutron symmetry symmetry and phonon structure of some low-lying states in 92 Zr is studied. structure of some low-lying states in 92 Zr is studied. The breaking of F-spin symmetry is confirmed, but The breaking of F-spin symmetry is confirmed, but the breaking mechanism is more complex than one the breaking mechanism is more complex than one suggested in the original shell model analysis of the suggested in the original shell model analysis of the data. The new intriguing features of the spectrum, data. The new intriguing features of the spectrum, such as a pronounced multiphonon fragmentation of such as a pronounced multiphonon fragmentation of the states and a tentative evidence of three-phonon the states and a tentative evidence of three-phonon mixed-symmetry state is found .mixed-symmetry state is found .

COLLABORATIONS•Dipartimento di Scienze Fisiche , •Universita di Napoli Federico II and •Istituto Nazionale di Fisica Nucleare, sezione di Napoli Complesso Monte S. Angelo, via Cintia I-80126, Napoli

SOME RECENT PUBLICATIONS:•N. Lo Iudice, Ch. Stoyanov, Microscopic description of newly discovered mixed symmetry states. Phys. Rev. C, v. 62 (2000) pp. 047302, 4p. •N. Lo Iudice, Ch. Stoyanov, Mroscopic Study of the Proton-Neutron Symmetry and Phonon Structure of the Low-Lying States in 92Zr., Phys. Rev. C, v. 69 (2004) p. 044312, 6p.

High-spin states in the neutron-richHigh-spin states in the neutron-rich nuclei withnuclei with

80 80 < < A A < < 150 150

produced as fission fragments produced as fission fragments (FF)(FF)

byby heavy ion reactions heavy ion reactions

collaboration betweencollaboration between CNRSCNRS//FranceFrance and BASand BAS::

Contracts NoContracts No 2937, 8198, 12531, 16946. 2937, 8198, 12531, 16946. IPN Orsay; IreS Strasbourg; CEA/DSM/DAPNIA/SPhN IPN Orsay; IreS Strasbourg; CEA/DSM/DAPNIA/SPhN Gif-sur-Gif-sur-Yvette; IPNL, Uni Claude Bernard, Villeurbanne; IPN LyonYvette; IPNL, Uni Claude Bernard, Villeurbanne; IPN Lyon, , France; Dep. of Phys., Dep.Phys.Astronomy University of France; Dep. of Phys., Dep.Phys.Astronomy University of Manchester, Manchester Manchester, Manchester

Fission Fragments (FF)

106,107,108,109,110,111,112,113Rh (Z=45), 110,112,114,116Ag (Z=47), 115,117,119,121In (Z=49), 121,123,125,127Sb (Z=51), 140Ba (Z=56), 142,143,145,147Ce (Z=58), 147,149Nd(Z=60)

11. . TsTs..VenkovaVenkova, , MM.-.-GG..Porquet, M.Houry, R.Lucas, Ch.Theisen, J.Durell and A.RoachPorquet, M.Houry, R.Lucas, Ch.Theisen, J.Durell and A.Roach

“ “A new high-spin level scheme for A new high-spin level scheme for 149149Nd from a fusion-fission reaction”Nd from a fusion-fission reaction” EurEur. . PhysPhys. . JJ. . AA 28, 14728, 147 (200 (20066)) 22. . TsTs..VenkovaVenkova, , MM.-.-GG..PorquetPorquet, , AA..AstierAstier, , II..DeloncleDeloncle, , PP..PetkovPetkov, , AA..PrevostPrevost, , FF..AzaiezAzaiez, ,

AA..BogachevBogachev, , AA..ButaButa, , DD..CurienCurien, , OO..Dorvaux, Dorvaux, GG..DucheneDuchene, , J.Durell, J.Durell, BB..JJ..PP..GallGall, , MM..HouryHoury, , FF..KhalfallahKhalfallah, , RR..LucasLucas, , MM..MeyerMeyer, , II..PiquerasPiqueras, , NN..RedonRedon, , A.Roach, A.Roach, MM..RousseauRousseau, , OO..StezowskiStezowski, , and and ChCh..TheisenTheisen

“ “New high-spin states of New high-spin states of 147147Nd and Nd and 145145Ce: Octupole correlation in the N = 87 Ce: Octupole correlation in the N = 87 isotones”isotones”

Eur.Phys. J. A 26, 315 (2005)Eur.Phys. J. A 26, 315 (2005)

33. . M.-G. Porquet, Ts.Venkova, M.-G. Porquet, Ts.Venkova, R.Lucas, R.Lucas, AA..AstierAstier,, A.Bauchet, I A.Bauchet, I..Deloncle, A.Prevost, Deloncle, A.Prevost, F.Azaiez, G.Barreau, A.Bogachev, N.Buforn, A.Buta, D.Curien, T.P.Doan, L.Donadille, F.Azaiez, G.Barreau, A.Bogachev, N.Buforn, A.Buta, D.Curien, T.P.Doan, L.Donadille, O.Dorvaux, G.Duchene, J.Durell, Th. Ethvignot, BO.Dorvaux, G.Duchene, J.Durell, Th. Ethvignot, B..JJ..PP..GallGall, , M.Houry, Ch.Theisen, M.Houry, Ch.Theisen, D.Grimwood, W.Korten, , S.Lalkovski, Y.Le Coz, MD.Grimwood, W.Korten, , S.Lalkovski, Y.Le Coz, M..MeyerMeyer, , A.Minkova, I.Piqueras, A.Minkova, I.Piqueras, N.Redon, A.Roach, M.Rousseau, N.Schulz, A.G.Smith, ON.Redon, A.Roach, M.Rousseau, N.Schulz, A.G.Smith, O..Stezowski, Ch.Theisen, and Stezowski, Ch.Theisen, and B.J.VarleyB.J.Varley

High-spin structure of High-spin structure of 121,123,125,127121,123,125,127SbSb nuclei: single proton and core-coupled nuclei: single proton and core-coupled states”states”

Eur. Phys. J. A 24, 39 (2005)Eur. Phys. J. A 24, 39 (2005)

44. . R.Lucas, M.-G. Porquet, Ts.Venkova,R.Lucas, M.-G. Porquet, Ts.Venkova, II..Deloncle, M.Houry, Ch.Theisen, Deloncle, M.Houry, Ch.Theisen, AA..AstierAstier,, A.Bauchet, S.Lalkovski, G.Barreau, N.Buforn, T.P.Doan, L.Donadille, A.Bauchet, S.Lalkovski, G.Barreau, N.Buforn, T.P.Doan, L.Donadille, O.Dorvaux, J.Durell, Th. Ethvignot, BO.Dorvaux, J.Durell, Th. Ethvignot, B..JJ..PP..GallGall,, D.Grimwood, W.Korten, Y.Le D.Grimwood, W.Korten, Y.Le Coz, MCoz, M..MeyerMeyer, , A.Minkova, A.Prevost, N.Redon, A.Roach, N.Schulz, A.Minkova, A.Prevost, N.Redon, A.Roach, N.Schulz, A.G.Smith, OA.G.Smith, O..Stezowski, B.J.VarleyStezowski, B.J.Varley

“ “High-spin study of High-spin study of odd-Aodd-A 4949InIn isotopes beyond the neutron mid-shell” isotopes beyond the neutron mid-shell” Eur. Phys. J. Eur. Phys. J. A 15, 315 (2002)A 15, 315 (2002)

5.5. M.-G. Porquet, Ts.Venkova, AM.-G. Porquet, Ts.Venkova, A..AstierAstier,, A.Bauchet, I A.Bauchet, I..Deloncle, N.Buforn, Deloncle, N.Buforn, L.Donadille, O.Dorvaux, BL.Donadille, O.Dorvaux, B..JJ..PP..GallGall,, S.Lalkovski, R.Lucas, M S.Lalkovski, R.Lucas, M..MeyerMeyer, , A.Minkova, A.Prevost, N.Redon, N.Schulz, OA.Minkova, A.Prevost, N.Redon, N.Schulz, O..StezowskiStezowski

“ “Evolution of the π g 9/2 ν h11/2 configuration in the neutron-rich Evolution of the π g 9/2 ν h11/2 configuration in the neutron-rich 110,112110,112Rh and Rh and 114,116114,116AgAg isotopes” isotopes”

Eur. Phys. J. A 18, 25 (2003)Eur. Phys. J. A 18, 25 (2003)

6. 6. MM.-.-GG..PorquetPorquet, , TsTs..VenkovaVenkova, , PP..PetkovPetkov, , AA..BauchetBauchet, , II..DeloncleDeloncle, , AA..AstierAstier, , NN..BufornBuforn, , JJ..DupratDuprat, , BB..JJ..PP..GallGall, , CC..GautherinGautherin, , EE..GueorgievaGueorgieva, , FF..HoellingerHoellinger, , TT..KutsarovaKutsarova, , RR..LucasLucas, , MM..MeyerMeyer, , AA..MinkovaMinkova, , NN..RedonRedon, , NN..SchulzSchulz, , HH..SergolleSergolle, , AA..WilsonWilson

“ “High-spin structure of the neutron-rich odd-odd High-spin structure of the neutron-rich odd-odd 106,108106,108Rh Rh and and 110,112110,112 Ag Ag isotopes”isotopes” Eur. Phys. J. A 15, 463 (2002)Eur. Phys. J. A 15, 463 (2002)

77. . TsTs..VenkovaVenkova, , MM.-.-GG..PorquetPorquet, , AA..AstierAstier, , AA..BauchetBauchet, , II..DeloncleDeloncle, , SS..LalkovskiLalkovski, , NN..BufornBuforn, , LL..DonadilleDonadille, , OO..DorvauxDorvaux, , BB..JJ..PP..GallGall, , RR..LucasLucas, , MM..MeyerMeyer, , AA..MinkovaMinkova, , AA..PrevostPrevost, , NN..RedonRedon, , NN..SchulzSchulz, , OO..StezowskiStezowski

“ “High-spin structure of the neutron-rich High-spin structure of the neutron-rich 109,111,113109,111,113RhRh isotopes” isotopes” Eur.Phys. J. A 15, 429 (2002)Eur.Phys. J. A 15, 429 (2002)

8. 8. MM.-.-GG..PorquetPorquet, , TsTs. . VenkovaVenkova,, AA..AstierAstier, , II..DeloncleDeloncle, , AA..PrevostPrevost, , FF..AzaiezAzaiez, , AA..ButaButa, , DD..CurienCurien, , GG..DucheneDuchene, , BB..JJ..PP..GallGall, , FF..KhalfallahKhalfallah, , II..PiquerasPiqueras, , MM..RousseauRousseau, , NN..RedonRedon, , MM..MeyerMeyer, , OO..StezowskiStezowski, , RR..LucasLucas, , AA. . BogachevBogachev

” ”Beyond the N = 50 shell closureBeyond the N = 50 shell closure: High-spin excitations of : High-spin excitations of 8787KrKr isotope and isotope and ground state spin of ground state spin of 8787BrBr””

Eur. Phys. J. A 28, 153 (200Eur. Phys. J. A 28, 153 (20066) )

Laboratory of Theoretical Nuclear Laboratory of Theoretical Nuclear PhysicsPhysics

SUPERSCALING ANALYSIS OF INCLUSIVE ELECTRON SUPERSCALING ANALYSIS OF INCLUSIVE ELECTRON SCATTERING AND ITS EXTENSION TO CHARGE- AND NEUTRAL-SCATTERING AND ITS EXTENSION TO CHARGE- AND NEUTRAL-

CURRENT NEUTRINO-NUCLEUS SCATTERING BEYOND THE CURRENT NEUTRINO-NUCLEUS SCATTERING BEYOND THE RELATIVISTIC FERMI GAS MODELRELATIVISTIC FERMI GAS MODEL

The superscaling analysis of inclusive electron scattering from nuclei in the quasielastic and delta-region is extended to calculate and to predict charge-changing neutrino (antineutrino) scattering [(νμ,μ-) and (νμ,μ+)] as well as of neutral current neutrino (antineutrino) scattering [(ν,N) and (ν,N)] on 12C at incident energies from 1 to 2 GeV. The calculations are performed using scaling function f(ψ') obtained in approaches beyond the Relativistic Fermi Gas model and mean-field approximation, such as Coherent Density Fluctuation Model and the Light-Front Dynamics Method. The analyses account for the nucleon-nucleon correlations in nuclei. It is found that the behavior of f(ψ') for ψ'<-1 depends on the particular form of the general power-low asymptotics of the momentum distribution n(k)~1/k4+m at large k. The best agreement with the experimental scaling function found for m≈4.5 gives a link to a corresponding particular behavior of the in medium NN forces around the core: VNN(r) goes to infinity for r→0 as 1/r or softer.

COLLABORATIONS•The Institute of the structure of matter, CSIC, and the Complutense University, Madrid, E-28040 Madrid, Spain (Prof. Elvira Moya de Guerra and Prof. J.M. Udias);•The University of Sevilla, Spain (Prof. J.A. Caballero)•The University of Torino, Italy (Prof. M.B. Barbaro)

SOME RECENT PUBLICATIONS:•A. N. Antonov, M. V. Ivanov, M. K. Gaidarov, E. Moya de Guerra, P. Sarriguren, and J. M. Udias, Phys. Rev. C 73, 047302 (2005).•A. N. Antonov, M. V. Ivanov, M. K. Gaidarov, E. Moya de Guerra, J. A. Caballero, M. B. Barbaro, J. M. Udias, and P. Sarriguren, Phys. Rev. C 74, 054603 (2006).•A. N. Antonov, M. V. Ivanov, M. K. Gaidarov, E. Moya de Guerra, nucl-th/0703003, Phys. Rev. C 75 (April 2007).

SUPERSCALING ANALYSIS OF INCLUSIVE ELECTRON SUPERSCALING ANALYSIS OF INCLUSIVE ELECTRON SCATTERING AND ITS EXTENSION TO CHARGE- AND NEUTRAL-SCATTERING AND ITS EXTENSION TO CHARGE- AND NEUTRAL-

CURRENT NEUTRINO-NUCLEUS SCATTERING BEYOND THE CURRENT NEUTRINO-NUCLEUS SCATTERING BEYOND THE RELATIVISTIC FERMI GAS MODELRELATIVISTIC FERMI GAS MODEL


EFFECTS OF NUCLEON CORRELATIONS ON CHARACTERISTICS EFFECTS OF NUCLEON CORRELATIONS ON CHARACTERISTICS OF NUCLEAR STRUCTURE AND REACTIONSOF NUCLEAR STRUCTURE AND REACTIONS

MODELS OF COMPLEX DEFORMED NUCLEI, SYMMETRIES AND MODELS OF COMPLEX DEFORMED NUCLEI, SYMMETRIES AND FINE STRUCTURE OF NUCLEAR SPECTRAFINE STRUCTURE OF NUCLEAR SPECTRA

MODELS OF COMPLEX DEFORMED NUCLEI, MODELS OF COMPLEX DEFORMED NUCLEI, SYMMETRIES AND FINE STRUCTURE OF SYMMETRIES AND FINE STRUCTURE OF

NUCLEAR SPECTRANUCLEAR SPECTRA

Collective model approaches are proposed for Collective model approaches are proposed for description of rotation and rotation-vibration description of rotation and rotation-vibration motion of nuclei with quadrupole and octupole motion of nuclei with quadrupole and octupole degrees of freedom. They are applied to study degrees of freedom. They are applied to study the fine structure of energy spectra, E1, E2, E3 the fine structure of energy spectra, E1, E2, E3 transition probabilities and complex shape transition probabilities and complex shape deformations in different nuclear regions.deformations in different nuclear regions.

COLLABORATIONSD. Bonatsos (Athens), W. Scheid (Giessen), R. Jolos (Dubna)

SOME RECENT PUBLICATIONS:N. Minkov, P. Yotov, S. Drenska and W. Scheid, J. Phys. G: Nucl. Part. Phys. 32, 497-509 (2006)

N. Minkov, P. Yotov, S. Drenska, W. Scheid, D. Bonatsos, D. Lenis and D. Petrellis, Phys. Rev. C 73, 044315 (2006)

N. Minkov, P. Yotov, R. V. Jolos and W. Scheid, J. Phys. G: Nucl. Part. Phys. 34 299-313 (2007)

Coherent quadrupole octupole modes in nucleiCoherent quadrupole octupole modes in nuclei Quadrupole-octupole potential, octupole band levels, B(E1) and B(E2)’s in Quadrupole-octupole potential, octupole band levels, B(E1) and B(E2)’s in 152152SmSm


EFFECTS OF NUCLEON CORRELATIONS ON CHARACTERISTICS EFFECTS OF NUCLEON CORRELATIONS ON CHARACTERISTICS OF NUCLEAR STRUCTURE AND REACTIONSOF NUCLEAR STRUCTURE AND REACTIONS

MODELS OF COMPLEX DEFORMED NUCLEI, SYMMETRIES AND MODELS OF COMPLEX DEFORMED NUCLEI, SYMMETRIES AND FINE STRUCTURE OF NUCLEAR SPECTRAFINE STRUCTURE OF NUCLEAR SPECTRA

APPLICATION OF THE ALGEBRAIC AND GEOMETRICAL APPLICATION OF THE ALGEBRAIC AND GEOMETRICAL ASPECTS OF DYNAMICAL SYMMETRIES IN THE DESCRIPTION ASPECTS OF DYNAMICAL SYMMETRIES IN THE DESCRIPTION

OF CRITICAL PHENOMENA IN THE DEVELOPMENT OF OF CRITICAL PHENOMENA IN THE DEVELOPMENT OF NUCLEAR COLLECTIVITY.NUCLEAR COLLECTIVITY.

APPLICATION OF THEAPPLICATION OF THE ALGEBRAIC AND ALGEBRAIC AND GEOMETRICAL ASPECTS OF DYNAMICAL GEOMETRICAL ASPECTS OF DYNAMICAL

SYMMETRIES IN THE DESCRIPTION OF CRITICAL SYMMETRIES IN THE DESCRIPTION OF CRITICAL PHENOMENA IN THE DEVELOPMENT OF NUCLEAR PHENOMENA IN THE DEVELOPMENT OF NUCLEAR

COLLECTIVITY.COLLECTIVITY.

The symplectic extensions of the boson and fermion The symplectic extensions of the boson and fermion representations of the convenient unitary algebras and representations of the convenient unitary algebras and their deformations are used to classify the basis states their deformations are used to classify the basis states that correspond to different types of experimentally that correspond to different types of experimentally observed collective spectra. In the framework of the observed collective spectra. In the framework of the so developed dynamical symmetries exact analytic so developed dynamical symmetries exact analytic solutions are obtained for the respective Hamiltonians solutions are obtained for the respective Hamiltonians that describe the mixed mode collective spectra, even that describe the mixed mode collective spectra, even at the critical points of phase/shape transitions. at the critical points of phase/shape transitions.

COLLABORATIONS Prof. J.P. Draayer, Department of Physics and Astronomy,

Louisiana State University, Baton Rouge, LA70803

SOME RECENT PUBLICATIONS: K. D. Sviratcheva, C. Bahri, A. I. Georgieva, and J. P.

Draayer, Physical Significance of q-Deformation and Many-Body Interactions in Nuclei, Phys. Rev. Lett. 93, 152501 (2004).

H. G. Ganev, A. I. Georgieva, and J. P. Draayer, Six-dimensional Davidson potential as a dynamical symmetry

of the symplectic interacting vector boson model, Phys. Rev. C 72, 014314 (2005).

Microscopic description of pairing-governed 0+ states in even A nuclei

-10 -5 5 10

-200

-100

100

200

300

400

A=56

1f5/2 2p1/2 2p3/2 1g9/2

• two-body interactions

• common nuclear properties

• two-body interactions

• common nuclear properties

Non-negligible higher-order many-body interactions (q) in regions of dominant pairing correlations

N–

N+

(n, i)

0

5

10

15

20

0

0.5

1

1.5

0

5

10

15

20

n

i

Smooth dependence on nuclear characteristics

Local non-linear effects (within individual nucleus)

• Two-proton drip line• N=Z irregularities• Pairing gaps• Staggering behavior

Interacting Vector Boson Model Application of new dynamical symmetries arising

in the symplectic extension of the model for the description of the

SUpn(3)

Sp(12,R) Sp(4,R) SO(3)

U(1,1)O(6)

O(2)

U(6) U(2) U(3)

Negative and possitive parity bands

6-D Davidson potential

States with fixed L

mixing of collective modes in the heavy even-even nuclei

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