15,960 research outputs found
Attitude control system Patent
Development of attitude control system for spacecraft orientatio
Neutrinos, Weak Interactions, and r-process Nucleosynthesis
Two of the key issues in understanding the neutron-to-proton ratio in a
core-collapse supernova are discussed. One of these is the behavior of the
neutrino-nucleon cross sections as supernova energies. The other issue is the
many-body properties of the neutrino gas near the core when both one- and
two-body interaction terms are included.Comment: To be published in the Proceedings of "International Symposium on
Structure of Exotic Nuclei and Nuclear Forces (SENUF 06)", March 2006, Tokyo,
Japa
On the asymmetry of Gamow-Teller beta-decay rates in mirror nuclei in relation with second-class currents
The theoretical evaluation of major nuclear structure effects on the
asymmetry of allowed Gamow-Teller beta-decay rates in light mirror nuclei is
presented. The calculations are performed within the shell model, using
empirical isospin-nonconserving interaction and realistic Woods-Saxon radial
wave functions. The revised treatment of p-shell nuclei is supplemented by
systematic calculations for sd-shell nuclei and compared to experimental
asymmetries when available. The results are important in connection with the
possible existence of second-class currents in the weak interaction.Comment: 16 pages, 6 figure
Singular point characterization in microscopic flows
We suggest an approach to microrheology based on optical traps in order to
measure fluid fluxes around singular points of fluid flows. We experimentally
demonstrate this technique, applying it to the characterization of controlled
flows produced by a set of birefringent spheres spinning due to the transfer of
light angular momentum. Unlike the previous techniques, this method is able to
distinguish between a singular point in a complex flow and the absence of flow
at all; furthermore it permits us to characterize the stability of the singular
point.Comment: 4 pages and 4 figure
Sun tracker with rotatable plane-parallel plate and two photocells Patent
Sun tracker with rotatable plane-parallel plate and two photocell
Possible CP-Violation effects in core-collapse Supernovae
We study CP-violation effects when neutrinos are present in dense matter,
such as outside the proto-neutron star formed in a core-collapse supernova.
Using general arguments based on the Standard Model, we confirm that there are
no CP-violating effects at the tree level on the electron neutrino and
anti-neutrino fluxes in a core-collapse supernova. On the other hand
significant effects can be obtained for muon and tau neutrinos even at the tree
level. We show that CP violating effects can be present in the supernova
electron (anti)neutrino fluxes as well, if muon and tau neutrinos have
different fluxes at the neutrinosphere. Such differences could arise due to
physics beyond the Standard Model, such as the presence of flavor-changing
interactions.Comment: 11 pages, 18 figure
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