328 research outputs found
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
Neutrino mixing in Seesaw model
We study the neutrino mixing matrix (the MNS matrix) in the seesaw model. By
assuming a large mass hierarchy for the heavy right-handed Majorana mass, we
show that, in the diagonal Majorana base, the MNS matrix is determined by a
unitary matrix, , which transforms the neutrino Yukawa matrix, ,
into a triangular form, . The mixing matrix of light leptons is
, where
% and diagonalize %the Yukawa matrices of charged leptons,
%, and neutrinos, ,
%respectively, and . Large mixing
may occur without fine tuning of the matrix elements of even if
the usual KM-like matrix is given by . This large mixing
naturally may satisfy the experimental lower bound of the mixing implied by the
atmospheric neutrino oscillation.Comment: 14 pages, 4 figures, PTPTe
Low scale Seesaw model and Lepton Flavor Violating Rare B Decays
We study lepton flavor number violating rare B decays, , in a seesaw model with low scale singlet Majorana neutrinos
motivated by the resonant leptogenesis scenario. The branching ratios of
inclusive decays with two almost
degenerate singlet neutrinos at TeV scale are investigated in detail. We find
that there exists a class of seesaw model in which the branching fractions of and can be as large as and
within the reach of Super B factories, respectively, without being in
conflict with neutrino mixings and mass squared difference of neutrinos from
neutrino data, invisible decay width of and the present limit of .Comment: 19 pages, 6 figure
An Interesting Fitting of Quark Masses
In this note we show an empirical formula of quark masses, which is found by
implementing a least squares fit. In this formula the measured QCD coupling is
almost a "best fitting coupling".Comment: 5 pages, 2 figure
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
- …