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Lifetime measurements in 128 Cs and 132 La as a test of chirality Kazimierz Dolny September 2005 Julian Srebrny Nuclear Physics Division Institute of Experimental Physics Warsaw University

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Three angular momentum vectors can form two systems of different handedness O operator acting on 3 vectors in a plane, does not change the handedness. O operator acting on 3 aplanar vectors does change the handedness.

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Where it can be find in nuclear case ? - three-axial even even core - one particle takes maximum overlap. - one hole takes minimum overlap example: 132 La 75 and 128 Cs 73 p(h 11/2 ) n -1 (h 11/2 ) three-axial core ( angular momentum R ) ( angular momentum p ) (angular momentum n -1 ) intrinsic system

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Restoration of the chiral symmetry in the laboratory reference frame forms two nearly degenerate bands: chiral partner bands

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Candidates for chiral partner bands identified in 10 odd-odd nuclei in A130 HIL Warsaw

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Experimental facility U200P Cyclotron 10 AntiCompton Shielded germanium spectrometers Heavy Ion laboratory Warsaw University Heavy Ion laboratory University of Warsaw Reactions 122 Sn ( 14 N,4n) 132 La 10mg/cm 2 70MeV 122 Sn ( 10 B,4n) 128 Cs 40mg/cm 2 55MeV Ge-Ge coincidences Doppler Shift Attenuation Method

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E detector Thick target N recoils Beam ions Doppler Shift Attenuation Method Doppler shifts, attenuated during the stopping process in the target, are analysed.

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Results of transition probabilities for 132 La Absolute transition probabilities are different in both bands. Transition probabilities in side band are 20 times smaller than in the yrast band. Int.J.Mod.Phys. E13, 243 (2004) E.Grodner, J.Srebrny, Ch.Droste, T.Morek, A.Pasternak, J.Kownacki

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The newest results for 128 Cs comparison with 132 La electromagnetic properties similar in both bands in 128 Cs. chiral symmetry can be broken. preliminary results in E.Grodner et al. HIL An..Rep.2004 http:/www.slcj.uw.edu.pl/reports/Report04.pdf

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B(M1) staggering is reproduced by the CQPHC calculations CQPHC results for 128 Cs theoretical calculations done in frame of CQPHC model - core properties taken from 128 Xe Phys. Rev. C67, 044319 (2003) T. Koike, K. Starosta, C.J. Chiara, D.B. Fossan, D.R. LaFosse

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E. Grodner, I. Zalewska, T. Morek, J. Srebrny, Ch. Droste, M. Kowalczyk, J. Mierzejewski, M. Sałata. Institute of Experimental Physics, Warsaw University, Warsaw, Poland A. A. Pasternak A. F. Ioffe Physical Technical Institute RAS, St. Petersburg, Russia J. Kownacki, M. Kisieliński, A. Kordyasz, P. Napiorkowski, M.Wolińska-Cichocka Heavy Ion Laboratory of Warsaw University, Warsaw, Poland L. Nowicki, R. Ratajczak, R. Kaczarowski, W. Płóciennik, E. Ruchowska, A. Wasilewski The Andrzej Sołtan institute for Nuclear Studies, Otwock-Świerk, Poland P.Olbratowski, J. Dobaczewski, S. G. Rohoziński, W. Satuła Institute of Theoretical Physics, Warsaw University, Warsaw, Poland

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1. New phenomena of chiral symmetry breaking first theoretical prediction Frauendorf, Meng 1997 interpretation of 134 Pr data Petrache et al. 1996 2. Experimental identification of chiral doublets based on energy levels only- about 10 cases for A 130 2001-2003 3. CPHC model formulated and firstly applied to 132 La K. Starosta et al. 2002 4. First self-consistent HF chiral solutions P. Olbratowski et al. 2002 5. First lifetime measurements in supposed chiral bands 132 La Warsaw Cyclotron and OSIRIS II,DSAM 2003 6. 128 Cs lifetime measurements Warsaw Cyclotron and OSIRIS II,DSAM 2004 128 Cs – the best case interpreted within chiral symmetry braking 2005 The important role of smaller accelerators for nonstandard idea

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Later on some usefull foils not presented at the Workshop

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Lifetimes in 132 La All lifetimes are in 0.5-1.5ps range. More than 20 lifetimes were measured. New band was discovered Lifetimes were recalculated to more than 40 absolute reduced transition probabilities

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Stopping power parameters for 132 La Stopping power parameters can be obtained from the velocity distribution of recoils Target thickness comarable with recoils range Observed transition from state living more then few picoseconds Velocity distribution depends only on the stopping process

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Stopping power parameters for 132 La

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Nucl.Phys. A292, 66 (1977) S.G.Rohozinski, J.Dobaczewski, B.Nerlo-Pomorska, K.Pomorski, J.Srebrny reference paper on triaxiality in A = 130 region of nuclei

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Energy splitting between partner bands This picture shown in 2003 supposed to proof the chirality discovery in atomic nucleus Phys.Rev. C65, 044328 (2002) K.Starosta, C.J.Chiara, D.B.Fossan, T.Koike, T.T.S.Kuo, D.R.LaFosse, S.G.Rohoziński, Ch.Droste, T.Morek, J.Srebrny

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