UK Physics & Astronomy Physics & Astronomy
Colloquium


Colloquium



3:30 PM, Friday, March 22, 2002


Room 155, Chem-Phys Building







Dr. Leonti Labzowsky


Departments of Physics
St. Petersburg State University





Parity Nonconservation Effects in Neutral Atoms and Highly Charged Ions





The recent situation with the parity nonconservation (PNC) effects in the neutral atoms is shortly reviewed . After the construction of the Unified Electroweak Theory by S.Weinberg, A.Salam and S.Glashow (1974) it became evident that the parity violating weak interaction should exist between the electrons and nuclei in atoms. The first atomic experiment that demonstrated the parity violation in Bi atoms ( the optical rotation ) was performed in Novosibirsk in 1978. Now the most accurate atomic PNC experiment is the measurement of the optical dichroism in Cs atom (C.S.Wood et al. 1997). Comparison with the different theoretical calculations leads to the controversial conclusions: probably this result contradicts to the Standard Model of Electroweak Interactions based on the parameters defined from the high-energy experiments. The reason for that is the difficulty of the accurate evaluation of the PNC effects in the many-electron atom due to the complexity of the electron correlation problem. Therefore it would be desirable to perform the PNC experiments on the simpler atomic systems. One of the best candidates are the two-electron highly charged ions with the nuclear charge numbers Z=63 (europium) and Z=92 (uranium). For these ions the PNC effects are strongly enhanced due to the near-degeneracy of the low-lying excited levels with opposite parity. The new type of the PNC atomic experiment is proposed - the measurement of the asymmetry of the photon emission relative to the ion beam polarization. The methods of obtaining the polarized ion beam are discussed. This experiment is included in the future program of investigations at the ion storage ring in GSI ( Darmstadt, Germany ).



*** Refreshments served at 3:15 PM ***


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