Münster 2011 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 3: Struktur und Dynamik von Kernen I

HK 3.4: Talk

Monday, March 21, 2011, 15:00–15:15, O-1

First combined DSAM and Coulex experiment at REX-ISOLDE - spectroscopic quadrupole moment of the 2₁⁺ state in neutron-rich ¹⁴⁰Ba * — •Christopher Bauer — Institut für Kernphysik, TU Darmstadt, Germany

The importance of precise lifetime information has recently been demonstrated in experiments at REX-ISOLDE and MINIBALL using the sensitivity of the Coulex yields to the nuclear reorientation effect in order to determine the sign of the spectroscopic quadrupole moment of the 2₁⁺ state in ⁷⁰Se [1,2]. Therefore we have utilized a new combined technique of lifetime measurement using the Doppler-Shift-Attenuation-Method (DSAM) and analysis of Coulex yields for the measurement of the spectroscopic quadrupole moment of the 2₁⁺ state in unstable neutron-rich ¹⁴⁰Ba. On the basis of the new lifetime of τ=12.5(6)ps it was possible to fix the sign of the spectroscopic quadrupole moment to be negative - equivalent to an oblate deformation. This is in agreement with recent Quasiparticle-phonon model calculations.

[1] A. M. Hurst et al., Phys. Rev. Lett. 98, 072501 (2007)

[2] J. Ljungvall et al., Phys. Rev. Lett. 100, 102502 (2008)
* supported by the BMBF (06DA9040I, 06DA9036I, 06MT238), EU (EURONS Nr. 506065), the MINIBALL/REX-ISOLDE collaborations and HIC for FAIR