11 research outputs found
Evaluation of the mean intensity of the P-odd mixing of nuclear compound states
A temperature version of the shell-optical-model approach for describing the
low-energy compound-to-compound transitions induced by external single-particle
fields is given. The approach is applied to evaluate the mean intensity of the
P-odd mixing of nuclear compound states. Unified description for the mixing and
electromagnetic transitions allows one to evaluate the mean intensity without
the use of free parameters. The valence-mechanism contribution to the mentioned
intensity is also evaluated. Calculation results are compared with the data
deduced from cross sections of relevant neutron-induced reactions.Comment: LaTeX, 10 page
The neutron and its role in cosmology and particle physics
Experiments with cold and ultracold neutrons have reached a level of
precision such that problems far beyond the scale of the present Standard Model
of particle physics become accessible to experimental investigation. Due to the
close links between particle physics and cosmology, these studies also permit a
deep look into the very first instances of our universe. First addressed in
this article, both in theory and experiment, is the problem of baryogenesis ...
The question how baryogenesis could have happened is open to experimental
tests, and it turns out that this problem can be curbed by the very stringent
limits on an electric dipole moment of the neutron, a quantity that also has
deep implications for particle physics. Then we discuss the recent spectacular
observation of neutron quantization in the earth's gravitational field and of
resonance transitions between such gravitational energy states. These
measurements, together with new evaluations of neutron scattering data, set new
constraints on deviations from Newton's gravitational law at the picometer
scale. Such deviations are predicted in modern theories with extra-dimensions
that propose unification of the Planck scale with the scale of the Standard
Model ... Another main topic is the weak-interaction parameters in various
fields of physics and astrophysics that must all be derived from measured
neutron decay data. Up to now, about 10 different neutron decay observables
have been measured, much more than needed in the electroweak Standard Model.
This allows various precise tests for new physics beyond the Standard Model,
competing with or surpassing similar tests at high-energy. The review ends with
a discussion of neutron and nuclear data required in the synthesis of the
elements during the "first three minutes" and later on in stellar
nucleosynthesis.Comment: 91 pages, 30 figures, accepted by Reviews of Modern Physic
Precise determination of the neutron scattering length of lead isotopes Pb, Pb and Pb by neutron interferometry
The neutron scattering length of lead isotopes Pb, Pb andPb are
determined by a set of neutron interferometry experiments. The obtained values fm, fm, fm have much higher accuracy then
current table data. Together with the precise value of b for natural lead, these results represent a
complete set of data and allow one to calculate fm, which is in the very good
agreement with the present day experimental value