4,556 research outputs found
Numerical study on the correlation between CP violation in neutrino oscillations and baryogenesis
We numerically study the correlation between CP violation in the neutrino
oscillations and baryogenesis in the seesaw model. In this study we get the
heavy Majorana neutrino masses and lepton number asymmetries from their decays
by fitting the data of neutrino oscillations and by working on some hypothesis
of the Dirac-Yukawa term for neutrinos.Comment: 3 pages, 2 figures, Latex, presented at KEKTC5(Nov. 2001), to be
published in Nucl. Phys. Proc. Supp
Cross-Border Political Donations and Pareto-Efficient Tariffs
This paper examines the effects of lobbying activities across international borders, on determining each country’s import tariff in a multi-principal, multi-agent, menu-auction model. Cross-border political donations could promote international policy cooperation because of two of their distinctive characteristics. First, special interest groups use cross-border donations as tools to wield their influence on ruling parties of other countries directly, which promotes efficiency of policy formation. Second, for ruling parties of countries, cross-border donations make them take into account the impact of their policy on other countries, which makes them more sensitive to other countries’ welfare and, therefore, more cooperative with others. When ruling parties estimate the worth of political contributions from national special interest groups and from foreign lobbying groups with the same weight, Pareto-efficient tariffs are attained at which world welfare is maximized.Cross-border Donations, Truthful Equilibrium, Pareto-Efficient Tariffs
Leptogenesis and Low energy CP violation, a link
How is CP violation of low energy related to CP violation required from
baryon number asymmetry ? We give an example which shows a direct link between
CP violation of neutrino oscillation and baryogenesis through leptogenesis.Comment: 3 pages and 2 figures, Talk presented at 4th Nufac02, July 1-6, 200
Primordial Lepton Family Asymmtries in Seesaw Model
In leptogenesis scenario, the decays of heavy Majorana neutrinos generate
lepton family asymmetries, and . They are sensitive to
CP violating phases in seesaw models. The time evolution of the lepton family
asymmetries are derived by solving Boltzmann equations. By taking a minimal
seesaw model, we show how each family asymmetry varies with a CP violating
phase. For instance, we find the case that the lepton asymmetry is dominated by
or depending on the choice of the CP violating phase. We
also find the case that the signs of lepton family asymmetries and
are opposite each other. Their absolute values can be larger than
the total lepton asymmetry and the baryon asymmetry may result from the
cancellation of the lepton family asymmetries.Comment: 26 pages, 8 figures, ptp.styl
Can a Preferential Trade Agreement Benefit Neighbor Countries without Compensating Them?
PTAs are generally negotiated without any tariff concessions or transfers to non-member countries. Can such a PTA benefit the neighbors’ welfare? In a two-good competitive equilibrium model in the absence of an entrepot, a PTA without concessions to the outsider will hurt the outsider’s welfare when goods are normal. If one of the member countries is an entrepot, however, it definitely improves the neighbors’ welfare. In a multiple-good model, a PTA without concessions deteriorates the neighbors’ welfare, provided that all the goods are normal and substitutes, and that initial tariff levels are small.PTA, Neighbor’s Welfare, Kemp-Wan theorem, WTO, GATT Article 24, Entrepot
Three Dimensional Heisenberg Spin Glass Models with and without Random Anisotropy
We reexamine the spin glass (SG) phase transition of the Heisenberg
models with and without the random anisotropy in three dimensions ()
using complementary two methods, i.e., (i) the defect energy method and (ii)
the Monte Carlo method. We reveal that the conventional defect energy method is
not convincing and propose a new method which considers the stiffness of the
lattice itself. Using the method, we show that the stiffness exponent
has a positive value () even when . Considering the
stiffness at finite temperatures, we obtain the SG phase transition temperature
of for . On the other hand, a large scale MC
simulation shows that, in contrary to the previous results, a scaling plot of
the SG susceptibility for is obtained using almost the
same transiton temperature of . Hence we believe that
the SG phase transition occurs in the Heisenberg SG model in .Comment: 15 pages, 9 figures, to be published in J. Phys.
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