Nuclear Physics

Juan Collar

See Prof. Collar's entry under Observational Astrophysics & Cosmology.

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Zheng-Tian Lu

See Prof. Lu's entry under Experimental Atomic Physics.

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GuyGuy Savard

Ph.D., McGill, 1988.
Senior Scientist, Physics Division, Argonne National Laboratory.
Professor (part time), Dept. of Physics, Enrico Fermi Institute.
Experimental physics, nuclear physics.

My current research is centered around low-energy tests of the Standard Model of electroweak interaction. These studies are performed on samples of radioactive ions captured in ion traps where they are available for high-precision experiments. New techniques developed by our group to efficiently capture short-lived isotopes of essentially any species in ion trap allow us to select isotopes with decay properties which enhance and isolate specific effects and hence increase our sensitivity to the physics of interest. The present experimental program is looking at a more precise determination of the weak vector coupling constant and a more precise test of CVC and the unitarity of the Cabibbo-Kobayashi-Maskawa matrix. A related experiment currently in preparation will search for scalar currents outside the standard V-A form for the charged electroweak interaction using samples of trapped superallowed emitters.

The type of experiment I am performing would greatly benefit from a more intense and versatile source of radioactive ions, and such a source has been assessed a high priority for new construction in nuclear physics in the US. I am therefore also heavily involved in the R&D for such a facility, which will use a novel technical approach for the fast extraction of the radioactive species based on some of the technologies we developed for ion trapping. (The leading contender for this facility is Argonne National Laboratory, located a short distance from Chicago.) More information on the proposed radioactive beam facility (RIA).

Selected Publications:

  • Precise Half-life Measurement for the Superallowed 0+ to 0+ beta-emitter 74Rb: First Results from ISAC, the New Radioactive Beam Facility at TRIUMF. G.C. Ball et al. Phys. Rev. Lett. 86, 1454, 2001.
  • Precision Nuclear Measurements with Ion Traps. G. Savard and G. Werth. Ann. Rev. of Nucl. and Part. Sci. 50, 119, 2000.
  • High-Accuracy Mass Determination of Cesium and Barium Isotopes. F. Ames et al. Nucl. Phys. A651, 3, 1999.
  • Weak Interaction Studies with an On-line Penning Trap Mass Spectrometer. G. Savard et al. Nucl. Phys. A654, 961c, 1999.
  • Beta+ Decay Partial Half-Life of 54Mn and Cosmic Ray Chronometry. A.H. Wuosmaa et al. Phys. Rev. Lett. 80, 2085, 1998.
  • Ion trap technology at accelerator facilities. G. Savard. Nucl. Instr. & Meth. B126, 361, 1997.
  • Pionic fusion of heavy ions. D. Horn et al. Phys. Rev. Lett. 77, 2408, 1996.
  • 10C superallowed branching ratio and the Cabibbo-Kobayashi-Maskawa matrix unitarity. G. Savard et al. Phys. Rev. Lett. 74, 1521, 1995.

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Updated 5/2001

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SchifferJohn P. Schiffer

Ph.D., Yale, 1954.
Senior Physicist, Physics Division, Argonne National Laboratory.
Professor Emeritus, Dept. of Physics, Enrico Fermi Institute.
Experimental physics, nuclear physics.

Search for simple symmetries in nuclear structure using heavy-ion reactions; understanding dynamics of interactions between nuclear systems.

Study of crystalline order, phase transitions, and degrees of freedom in confined ionic systems in ion beams and ion traps.

Search for exotic objects in nature; e.g., particles of integral charge but anomalous mass such as strangelets, electron-positron peaks observed in conjunction with very high electromagnetic fields, "17-keV" neutrinos, etc.

Measurement of nuclear properties that are important in the processes of nucleosynthesis, with particular attention to the breakout point from the hot CNO cycle that is crucial in producing elements heavier than oxygen, and to the properties of some of the nuclei that are the principal visible remnants of supernova explosions.

Selected Publications:

  • The 44Ti(a,p) Reaction and its Implication on the 44Ti Yield in Supernovae. A. Sonzogni et al. Phys. Rev. Lett. 84,1651, 2000.
  • Temperature, Ordering, and Equilibrium with Time-Dependent Confining Forces. J. P. Schiffer et al. Proc. Nat. Ac. Sc. 97, 10697, 2000.
  • Nuclear Physics: The Core of Matter, The Fuel of Stars. Committee on Nuclear Physics, National Research Council. National Academy Press, Washington, D.C., 1999.
  • Stellar Reactions with Short-Lived Nuclei: 17F(p,a)14O. B. Harss et al. Phys. Rev. Lett. 82, 3964, 1999.
  • Study of the 56Ni(d,p) Reaction and the Astrophysical 56Ni(p,g) Reaction Rate. K.E. Rehm et al. Phys. Rev. Lett. 80, 676, 1998.
  • Positron-Electron Correlations in Internal Pair Conversion. A.H. Wuosmaa et al. Phys. Rev. C57, R2794, 1998.
  • Sympathetic Crystallization of Trapped Ions. P. Bowe et al. Phys. Rev. Lett. 82, 2071, 1998.

Updated 5/2001

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