Parity Non-Conservation in the Decay of Polarized —

Parity Non-Conservation in the Decay of Polarized - Isomers in 93 Tc 17/2 B. S. Nara Singh 1, M. Hass 1, G. Goldring 1, D. Ackerman 2, J. Gerl 2, F. P. Hessberger 2, S. Hofmann 2, P. 2, H. Schaffner 2, B. Sulignano 2, B. A. Brown Kuusiniemi 1. Weizmann Institute of Science, ISRAEL, 2. GSI, GERMANY, 3. NSCL, Michigan, USA. PNC in Nuclei • • Non-leptonic, Non-strangeness changing. Probes HWeak of Nuclear Hamitonian. Etablishes IS, IV and IT strengths. Parity mixing in Nuclear levels: can be Observed through their Eletro Magnetic and Strong decays. Exp. Method • Polarization: Tilted Foil Technique. • 0 -180° Asymmetry (A ) in the M 2/E 3( ) -decay due to E 2 Component • Only Few Cases 19 F 21 Ne 30 me. V pl = 0. 15 known from QP interaction measurements M. Hass et al. , PRC 43, 2140. e. V 90 me. V 93 Tc Results ~ 0. 59 (31) me. V 180 Hf~1. 0(0. 1) 18 F Beam current fluctuation and experimental artifacts 1 mg/cm 2 SHIP, GSI 93 Tc Independent of Gamma efficiency Previous work at SHIP-GSI, RMS-LNL: M. Hass et al. , PLB 371, 25 45 Sc ~380(100) me. V Triple Ratios, A High Spin Isomer 16 foils, @70º 15 -15 g/cm 2 PLB, 371, 25: A = 8. 4(2. 7). 10 -4 , =0. 59(19)(25) me. V Setup • Parity doublet at 300 e. V Proximity. • N=50, Reasonable nuclear Structure Calculations within Shell model. • Establishes IT component and complementary to the studies in light nuclei. • Unique case For non-zero PNC. Isomer Beam • • 2 p 2 n)93 Tc Elab(93 Tc) = 65 Me. V SHIP: Tranfers to Focal Plane Area E-degrader 0. 2 mg/cm 2 avoids foil stack damage. SHIP optimization: PSD at the Entrance of Foils and gamma counting. Present+PLB, 371, 25: A = 4. 8 (2. 1). 10 -4 , =0. 34(14)(25) me. V 45 Sc(52 Cr, • • • Acquisition system upgraded to handle high counting rates. VME-CPU and Labview control. Counts in 751 ke. V line, 6 M per crystal Theory: 1 p 1/2 -0 g 9/2 with IV strength correction by an empirical factor of 0. 15± 0. 15. = - 0. 2 to 1 me. V