3,448 research outputs found

    Affleck-Dine baryo/leptogenesis with a gauged U(1)(B-L)

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    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 U(1)BLU(1)_{B-L} symmetry naturally solves this problem. Here, the breaking scale of the U(1)BLU(1)_{B-L} can be determined quite independently of the reheating temperature from the required baryon asymmetry. It is extremely interesting that the obtained scale of the U(1)BLU(1)_{B-L} 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 U(1)BLU(1)_{B-L} 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

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    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 MRM_R, 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

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    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)

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    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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