3,448 research outputs found
Affleck-Dine baryo/leptogenesis with a gauged U(1)(B-L)
We briefly review the present status of Affleck-Dine baryo/leptogenesis
scenarios in the minimal supersymmetric standard model (MSSM) in the context of
the gravity-mediated SUSY breaking, and show that there is a serious
cosmological problem in the Affleck-Dine mechanism. That is, the late decay of
the associated large Q-balls leads to the over production of the lightest
supersymmetric particles. Then, we point out that the minimal extension of the
MSSM by introducing a gauged symmetry naturally solves this
problem. Here, the breaking scale of the can be determined quite
independently of the reheating temperature from the required baryon asymmetry.
It is extremely interesting that the obtained scale of the
breaking is well consistent with the one suggested from the seesaw mechanism to
explain the recent neutrino-oscillation experiments. We consider that the
present scenario provides a new determination of the breaking
scale fully independent of the neutrino masses. We also comment on viability of
the present scenario in anomaly-mediated SUSY breaking models.Comment: 19 pages, revtex, no figur
Supersymmetric seesaw model for the (1+3)-scheme of neutrino masses
A four-neutrino spectrum with a sterile neutrino without significant
involvement in the atmospheric and solar neutrino oscillation experiments has
been recently advocated as the correct picture to explain all existing
experimental data. We propose a supersymmetric model in which this picture can
be naturally implemented. In this model, the mass for the mainly active
neutrino eigenstates is induced by the seesaw mechanism with a large
intermediate scale , whereas the mass for the mainly sterile neutrino
state is closely related to supersymmetry breaking.Comment: 9 page
Theory of Interaction of Memory Patterns in Layered Associative Networks
A synfire chain is a network that can generate repeated spike patterns with
millisecond precision. Although synfire chains with only one activity
propagation mode have been intensively analyzed with several neuron models,
those with several stable propagation modes have not been thoroughly
investigated. By using the leaky integrate-and-fire neuron model, we
constructed a layered associative network embedded with memory patterns. We
analyzed the network dynamics with the Fokker-Planck equation. First, we
addressed the stability of one memory pattern as a propagating spike volley. We
showed that memory patterns propagate as pulse packets. Second, we investigated
the activity when we activated two different memory patterns. Simultaneous
activation of two memory patterns with the same strength led the propagating
pattern to a mixed state. In contrast, when the activations had different
strengths, the pulse packet converged to a two-peak state. Finally, we studied
the effect of the preceding pulse packet on the following pulse packet. The
following pulse packet was modified from its original activated memory pattern,
and it converged to a two-peak state, mixed state or non-spike state depending
on the time interval
Heat Transfer Characteristics of Regenerator Matrix (Case of Packed Wire Gauzes)
The average heat transfer coefficient in the matrix of laminated wire screens (10 to 250 mesh) for a Stirling engine heat exchanger was studied experimentally. The data are correlated by N sub ud = 0.42 R sub ed 0.56 (3 or = R sub ed or = 400), and R sub ed are the Nusselt and Reynolds nubmers based on the wire diameter. The pressure drop decreased and the heat transfer increased as the wire diameter was decreased
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