Statistical properties of many-particle spectra VI. Fluctuation bounds on N--N T-noninvariance

Journal Article · Mon Feb 01 04:00:00 EST 1988 · Ann. Phys. (N.Y.); (United States)

DOI:https://doi.org/10.1016/0003-4916(88)90166-2· OSTI ID:7111105

French, J B; Kota, V K.B.; Pandey, A; Tomsovic, S

The preceding paper (V) shows that fluctuation analysis applied to experimental data in a chaotic region of the nuclear spectrum, determines values or bounds for a parameter ..lambda.., proportional to the mean-squared near-diagonal matrix element of a symmetry-breaking interaction. The immediate interest is with time-reversal invariance (TRI) for which bounds, not values, are found. We show here how this information can be reduced to a bound on ..cap alpha.., the relative magnitude of the time-reversal noninvariant (TRNI) part of the nucleon-nucleon interaction. This is done in terms of the level and transition-strength densities, both given as explicit functions of the Hamiltonian parameters. It is shown that, just as univariate Gaussian densities are essential ingredients of the state density, so also bivariate Gaussians enter naturally into a theory for the transition strengths. Calculations made for a subset, namely /sup 167,169/Er, /sup 233/Th, and /sup 239/U, of the nuclei considered in (V), give ..cap alpha..approx. <2 x 10/sup -3/, a value which by some arguments is at the boundary of fundamental interest. It is found that ..lambda..D..cap alpha../sup 2/ is roughly constant over the periodic table and varies only slowly with energy. This implies that, for ..cap alpha..-bounds better by perhaps a factor 4 (or ..cap alpha..-values), we need more small strengths in nuclei with small spacings such as /sup 236/U (which presently yields no ..lambda..-bound). The methods introduced here, which admit a number of simplifying approximations, are applicable to TRI studies via detailed-balance experiments proceeding through a compound nucleus, to other symmetries, and to a wide class of other problems. copyright 1988 Academic Press, Inc.

• Research Organization: Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627
• OSTI ID: 7111105
• Journal Information: Ann. Phys. (N.Y.); (United States), Journal Name: Ann. Phys. (N.Y.); (United States) Vol. 181:2; ISSN APNYA
• Country of Publication: United States
• Language: English

Related Subjects

653001* -- Nuclear Theory-- Nuclear Structure
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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
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URANIUM 239
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