169Re

Future Triaxial StudiesFuture Triaxial Studies• What role does the proton Fermi Surface What role does the proton Fermi Surface

have in the observation of wobbling?have in the observation of wobbling?– Search for wobbling in Search for wobbling in 169169Re (approved)Re (approved)

161Lu

175Hf174Hf173Hf170Hf171Hf162Lu

168Hf 172Hf163Lu164Lu165Lu 168Lu167Lu

90 92 94 96 98 100 102

171Ta167Ta

161Tm

165Ta

SD seen, but no wobbling

Wobblingobserved

163Tm

169Ta

Future Triaxial StudiesFuture Triaxial Studies• Does the iDoes the i13/213/2 sequence in sequence in 167167Ta show Ta show

evolution from evolution from = 0 = 0oo to 20 to 20oo??– High-statistics lifetime experimentHigh-statistics lifetime experiment

161Lu

175Hf174Hf173Hf170Hf171Hf162Lu

168Hf 172Hf163Lu164Lu165Lu 168Lu167Lu

90 92 94 96 98 100 102

171Ta167Ta

161Tm

165Ta

SD seen, but no wobbling

Wobblingobserved

163Tm

169Ta

Future Triaxial StudiesFuture Triaxial Studies• Return to heavier HfReturn to heavier Hf• Why do even-even show so many SD Why do even-even show so many SD

bands while odd-A typically only have one?bands while odd-A typically only have one?• High-statistics run to observed linking High-statistics run to observed linking

transitions in transitions in 173,174173,174HfHf

161Lu

175Hf174Hf173Hf170Hf171Hf162Lu

168Hf 172Hf163Lu164Lu165Lu 168Lu167Lu

90 92 94 96 98 100 102

171Ta167Ta

161Tm

165Ta

SD seen, but no wobbling

Wobblingobserved

163Tm

169Ta

3 2 3 81 1 2

Equipment, computer Equipment, computer needs…needs…• Just need Gammasphere Just need Gammasphere • Digital DAQ would require fewer days Digital DAQ would require fewer days

to perform high-statistics to perform high-statistics experimentsexperiments

Plans with CARIBUPlans with CARIBU

Predicted Stable Triaxiality at Predicted Stable Triaxiality at High Spin in N-Rich Mo and Ru High Spin in N-Rich Mo and Ru NucleiNuclei• Skalski et al. find Skalski et al. find

stable stable γγ minimumminimum• Also see superdefAlso see superdef• J. Hamilton et al. & J. Hamilton et al. &

C.Y. Wu et al. pushed C.Y. Wu et al. pushed up around I=20up around I=20

• Safe Coulex to Safe Coulex to measure Qmeasure Q00

• Unsafe Coulex to go Unsafe Coulex to go beyond I=20beyond I=20

J. Skalski et al., NPA 617, 282 (1997)

Equipment, computer Equipment, computer needs…needs…• Need Gammasphere Need Gammasphere • Chico or Super-ChicoChico or Super-Chico

Hercules Projects…Hercules Projects…

nw=1

nw=2

• Triaxial nucleus allows Triaxial nucleus allows rotation about all 3 axesrotation about all 3 axes

• Collective angular momentum Collective angular momentum vector lies off principal axis vector lies off principal axis – Precession + WobblingPrecession + Wobbling

• Amount it lies off axis Amount it lies off axis quantized into wobbling quantized into wobbling phonons (nphonons (nww))

• See a family of bands based See a family of bands based on same configuration on same configuration (different n(different nww))

• Bands are linked togetherBands are linked together– I = 1 have dominant E2 natureI = 1 have dominant E2 nature

• Bands have similar propertiesBands have similar properties– Moments of inertia, quadrupole Moments of inertia, quadrupole

moment, alignmentmoment, alignmentD.R. Jensen et al., PRL 89, 142503 (02)

Direct Evidence of Direct Evidence of Triaxiality?Triaxiality?163Lu nw=0

The Continued Pursuit of The Continued Pursuit of Stable TriaxialityStable Triaxiality• Near Future:Near Future:

– Wobbling bands in tantalum nucleiWobbling bands in tantalum nuclei• Not-too-distant FutureNot-too-distant Future

– A ~ 110 neutron-rich nuclei through CARIBU A ~ 110 neutron-rich nuclei through CARIBU

STABLETRIAXIALITY ME