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Anomalous behaviour of 2 + excitations around 132 Sn

Instituto de Estructura de la Materia – Consejo Superior de Investigaciones Científicas. Anomalous behaviour of 2 + excitations around 132 Sn. S. Pietri, A. Jungclaus, R. Orlandi, D. Rudolph, A. Gadea et al.

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Anomalous behaviour of 2 + excitations around 132 Sn

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  1. Instituto de Estructura de la Materia – Consejo Superior de Investigaciones Científicas Anomalous behaviour of 2+ excitations around 132Sn S. Pietri, A. Jungclaus, R. Orlandi, D. Rudolph, A. Gadea et al. GSI Darmstadt, IEM-CSIC Madrid, Lund University, IFIC-CSIC Valencia …

  2. Anomalous behaviour of 2+ excitations around 132Sn Te B(E2) anomaly Cd E(2+) anomaly ? What is the origin of these anomalies ?

  3. The anomalous behaviour of E(2+) in the Cd isotopes Compare 48Cd and 52Te isotopic chains ! Beyond-mean-field calculations with particle number and angular momentum projection T.R. Rodríguez, J.L. Egido, A. Jungclaus Physics Letters B668 (2008) 410 Cd E(2+) anomaly Calculations reproduce qualitatively the diffe- rent behaviour !

  4. Deformation as the main cause for the 2+ energy anomaly in the Cd isotopes towards N=82 peculiar coincidence of closed shell proton and neutron configurations “blocking” of the oblate branch, where 128Cd behaves as doubly-magic nucleus 128Cd 132Te prolate deformation of the 2+ state T.R. Rodríguez, J.L. Egido, A. Jungclaus Physics Letters B668 (2008) 410 2+

  5. The anomalous behaviour of B(E2) in the Te isotopes Te B(E2) anomaly ? slight E(2+) and B(E2) asymmetries with respect to N=82 E(2+) for N=82+x < E(2+) for N=82-x B(E2) for N=82+x > B(E2) for N=82-x except for the Te isotopes ! with Habs’ factor Raman’s version of Grodzins’ formula

  6. The anomalous behaviour of B(E2) in the Te isotopes B(E2) = 0.103(15) e2b2 from low-energy Coulex D. Radford et al., Phys. Rev. Lett. 88 (2002) 222501 D. Radford et al., Nucl. Phys. A752 (2005) 264c reanayzing the data yielded slightly larger value D. Radford, private communication ? B(E2) = 0.122(24) e2b2 from lifetime measurement (fast timing) L.M. Fraile, H. Mach et al., Nucl. Phys. A805 (2008) 218 shell model B(E2) = 0.25 e2b2 D. Radford, A. Covello et al., Phys. Rev. Lett. 88 (2002) 222501 Remeasure B(E2) in 136Te with good precision, measure B(E2) in 138Te for the first time ! QRPA B(E2) = 0.09 e2b2 J. Terasaki et al., Phys. Rev. C66 (2002) 054313 shell model B(E2) = 0.15 e2b2 beyond-mean-field study underway N. Shimizu, T. Otsuka et al., Phys. Rev. C 70 (2004) 054313

  7. The rate estimate Primary beam: 238U @ 650 MeV/u intensity 109/s Production target: 2.2 g/cm2 Be S4 rates: 1400 ions/s for 136Te and 130 ions/s for 138Te Reaction target: 0.5 g/cm2 Au at S4 Coulomb excitation cross section: 190 mb for 136Te (from known B(E2)) g-ray efficiency: eg=0.10 (606 resp. 443 keV for 136Te resp. 138Te) Particle-g coincidence rate: 3500 per day for 136Te 325 per day for 138Te Rates allow for B(E2) measurements with good precision ! P.S.: normalization with known B(E2) in 136,138Xe contaminants

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