Ultrahigh-Resolution {gamma}-Ray Spectroscopy of {sup 156}Gd: A Test of Tetrahedral Symmetry

Journal Article · Fri Jun 04 00:00:00 EDT 2010 · Physical Review Letters

DOI:https://doi.org/10.1103/PHYSREVLETT.104.222502· OSTI ID:21410381

Jentschel, M; Krempel, J ^[1]; Urban, W ^[1]; Tonev, D; Petkov, P ^[2]; Dudek, J; Curien, D ^[3]; Lauss, B ^[4]; Angelis, G de ^[5]

---

1. Institut Laue-Langevin, 6 rue Jules Horowitz, BP 156, F-38042 Grenoble (France)
2. Institute for Nuclear Research and Nuclear Energy, BAS, BG-1784 Sofia (Bulgaria)
3. Departement de Recherches Subatomiques, Institut Pluridisciplinaire Hubert Curien, DRS-IPHC, 23 rue du Loess, BP 28, F-67037 Strasbourg (France)
4. Paul Scherrer Institut, CH-5232 Villigen-PSI (Switzerland)
5. Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy)

Tetrahedral symmetry in strongly interacting systems would establish a new class of quantum effects at subatomic scale. Excited states in {sup 156}Gd that could carry the information about the tetrahedral symmetry were populated in the {sup 155}Gd(n,{gamma}){sup 156}Gd reaction and studied using the GAMS4/5 Bragg spectrometers at the Institut Laue-Langevin. We have identified the 5{sub 1}{sup -{yields}}3{sub 1}{sup -} transition of 131.983(12) keV in {sup 156}Gd and determined its intensity to be 1.9(3)x10{sup -6} per neutron capture. The lifetime {tau}=220{sub -30}{sup +180}fs of the 5{sub 1}{sup -} state in {sup 156}Gd has been measured using the GRID technique. The resulting B(E2)=293{sub -134}{sup +61}Weisskopf unit rate of the 131.983 keV transition provides the intrinsic quadrupole moment of the 5{sub 1}{sup -} state in {sup 156}Gd to be Q{sub 0}=7.1{sub -1.6}{sup +0.7} b. This large value, comparable to the quadrupole moment of the ground state in {sup 156}Gd, gives strong evidence against tetrahedral symmetry in the lowest odd-spin, negative-parity band of {sup 156}Gd.

• OSTI ID: 21410381
• Journal Information: Physical Review Letters, Vol. 104, Issue 22; Other Information: DOI: 10.1103/PhysRevLett.104.222502; (c) 2010 The American Physical Society; ISSN 0031-9007
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
CAPTURE
EXCITED STATES
GADOLINIUM 155
GADOLINIUM 156
GAMMA SPECTROSCOPY
GROUND STATES
INTERATOMIC FORCES
KEV RANGE
LIFETIME
MEASURING METHODS
NEUTRON REACTIONS
NUCLEAR STRUCTURE
PARITY
QUADRUPOLE MOMENTS
RESOLUTION
SPECTROMETERS
SPIN
SYMMETRY
ANGULAR MOMENTUM
BARYON REACTIONS
ENERGY LEVELS
ENERGY RANGE
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
GADOLINIUM ISOTOPES
HADRON REACTIONS
INTERMEDIATE MASS NUCLEI
ISOTOPES
MEASURING INSTRUMENTS
NUCLEAR REACTIONS
NUCLEI
NUCLEON REACTIONS
PARTICLE PROPERTIES
RARE EARTH NUCLEI
SPECTROSCOPY
STABLE ISOTOPES