Ultrahigh-Resolution gamma-Ray Spectroscopy of Gd-156: A Test of Tetrahedral Symmetry
Jun 4, 2010
4 pages
Published in:
- Phys.Rev.Lett. 104 (2010) 222502
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Abstract: (APS)
Tetrahedral symmetry in strongly interacting systems would establish a new class of quantum effects at subatomic scale. Excited states in Gd156 that could carry the information about the tetrahedral symmetry were populated in the Gd155(n,γ)Gd156 reaction and studied using the GAMS4/5 Bragg spectrometers at the Institut Laue-Langevin. We have identified the 51−→31− transition of 131.983(12) keV in Gd156 and determined its intensity to be 1.9(3)x10−6 per neutron capture. The lifetime τ=220−30+180fs of the 51− state in Gd156 has been measured using the GRID technique. The resulting B(E2)=293−134+61Weisskopf unit rate of the 131.983 keV transition provides the intrinsic quadrupole moment of the 51− state in Gd156 to be Q0=7.1−1.6+0.7 b. This large value, comparable to the quadrupole moment of the ground state in Gd156, gives strong evidence against tetrahedral symmetry in the lowest odd-spin, negative-parity band of Gd156.- 27.60.+j
- 27.70.+q
- 21.10.Tg
- 23.20.-g
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