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.

Lifetime measurements in 128Cs and 132Laas a test of chirality

Kazimierz Dolny September 2005

Julian Srebrny

Nuclear Physics Division

Institute of Experimental Physics

Warsaw University

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.

Where it can be find in nuclear case ?

- three-axial even even core - one particle takes maximum overlap. - one hole takes minimum overlap

example: 132La75 and 128Cs73

p(h11/2) n-1(h11/2 ) three-axial core

( angular momentum R )( angular momentum p )(angular momentum n-1)

intrinsic system

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

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

HIL Warsaw

Experimental facility

U200P Cyclotron

10 AntiCompton Shielded germanium spectrometers

Heavy Ion laboratory Warsaw University

Heavy Ion laboratoryUniversity of Warsaw

Reactions 122Sn (14N,4n)132La 10mg/cm2 70MeV

122Sn (10B,4n)128Cs 40mg/cm2 55MeV

Ge-Ge coincidences

Doppler Shift Attenuation Method

E

detector

Thick target

N

recoils

Beam ions

Doppler Shift Attenuation Method

Doppler shifts, attenuated during the stopping process in the target, are analysed.

12 14 16 18 20

1

10

100 Intraband transitions

132La

B(E

2,I-

>I-

2) [W

.u.]

I [h]

yrast band side band

Results of transition probabilities for 132La

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

The newest results for 128Cs comparison with 132La

electromagnetic properties similar in both bands in 128Cs.

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

B(M1) staggering is reproduced by the CQPHC calculations

CQPHC results for 128Cs

theoretical calculations done in frame of CQPHC model - core properties taken from 128Xe

Phys. Rev. C67, 044319 (2003)

T. Koike, K. Starosta, C.J. Chiara, D.B. Fossan, D.R. LaFosse

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. PasternakA. 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. SatułaInstitute of Theoretical Physics, Warsaw University, Warsaw, Poland

1. New phenomena of chiral symmetry breaking first theoretical prediction Frauendorf, Meng 1997 interpretation of 134Pr 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 132La 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 132La Warsaw Cyclotron and OSIRIS II,DSAM 2003

6. 128Cs lifetime measurements Warsaw Cyclotron and OSIRIS II,DSAM 2004

128Cs – the best case interpreted within chiral symmetry braking 2005

The important role of smaller accelerators for nonstandard idea

Later on some usefull foilsnot presented at the Workshop

Lifetimes in 132La

All lifetimes are in 0.5-1.5ps range.

More than 20 lifetimes were measured.

New band was discoveredLifetimes were recalculated

to more than 40 absolute reduced transition

probabilities

Stopping power parameters for 132La

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

Stopping power parameters for 132La

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

Energy splitting between partner bands

This picture shown in 2003supposed to proof the chirality discoveryin 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