CERN Accelerating science

Article
Title	Spin, quadrupole moment, and deformation of the magnetic-rotational band head in (193)Pb
Author(s)	Balabanski, D L (Sofiya, Inst. Nucl. Res. ; Leuven U.) ; Ionescu-Bujor, M (Bucharest, IFIN-HH) ; Iordachescu, A (Bucharest, IFIN-HH) ; Bazzacco, D (INFN, Padua ; Padua U.) ; Brandolini, F (INFN, Padua ; Padua U.) ; Bucurescu, D (Bucharest, IFIN-HH) ; Chmel, S (Bonn U., HISKP) ; Danchev, M (Sofiya U.) ; De Poli, M (INFN, Legnaro) ; Georgiev, G (CSNSM, Orsay) ; Haas, H (CERN ; Hahn-Meitner Inst.) ; Hubel, H (Bonn U., HISKP) ; Marginean, N (INFN, Legnaro ; INFN, Padua ; Padua U. ; Bucharest, IFIN-HH) ; Menegazzo, R (INFN, Padua ; Padua U.) ; Neyens, G (Leuven U.) ; Pavan, P (INFN, Padua ; Padua U.) ; Rossi Alvarez, C (INFN, Padua ; Padua U.) ; Ur, C A (INFN, Padua ; Padua U. ; Bucharest, IFIN-HH) ; Vyvey, K (Leuven U.) ; Frauendorf, S (Notre Dame U.)
Publication	2011
In:	Phys. Rev. C 83 (2011) 014304
DOI	10.1103/PhysRevC.83.014304
Subject category	Nuclear Physics - Experiment
Abstract	The spectroscopic quadrupole moment of the T(1/2) = 9.4(5) ns isomer in (193)Pb at an excitation energy E(ex) = (2585 + x) keV is measured by the time-differential perturbed angular distribution method as vertical bar Q(s)vertical bar = 2.6(3) e b. Spin and parity I(pi) = 27/2(-) are assigned to it based on angular distribution measurements. This state is the band head of a magnetic-rotational band, described by the coupling of a neutron hole in the 1i(13/2) subshell with the (3s(1/2)(-2)1h(9/2)1i(13/2))(11-) proton excitation. The pairing-plus-quadrupole tilted-axis cranking calculations reproduce the measured quadrupole moment with a moderate oblate deformation epsilon(2) = -0.11, similar to that of the 11(-)proton intruder states, which occur in the even-even Pb nuclei in the region. This is the first direct measurement of a quadrupole moment and thus of the deformation of a magnetic-rotational band head.

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