2,071 research outputs found
A Unified Description of Quark and Lepton Mass Matrices in a Universal Seesaw Model
In the democratic universal seesaw model, the mass matrices are given by
\bar{f}_L m_L F_R + \bar{F}_L m_R f_R + \bar{F}_L M_F F_R (f: quarks and
leptons; F: hypothetical heavy fermions), m_L and m_R are universal for up- and
down-fermions, and M_F has a structure ({\bf 1}+ b_f X) (b_f is a
flavour-dependent parameter, and X is a democratic matrix). The model can
successfully explain the quark masses and CKM mixing parameters in terms of the
charged lepton masses by adjusting only one parameter, b_f. However, so far,
the model has not been able to give the observed bimaximal mixing for the
neutrino sector. In the present paper, we consider that M_F in the quark
sectors are still "fully" democratic, while M_F in the lepton sectors are
partially democratic. Then, the revised model can reasonably give a nearly
bimaximal mixing without spoiling the previous success in the quark sectors.Comment: 7 pages, no figur
Phenomenological approach to the critical dynamics of the QCD phase transition revisited
The phenomenological dynamics of the QCD critical phenomena is revisited.
Recently, Son and Stephanov claimed that the dynamical universality class of
the QCD phase transition belongs to model H. In their discussion, they employed
a time-dependent Ginzburg-Landau equation for the net baryon number density,
which is a conserved quantity. We derive the Langevin equation for the net
baryon number density, i.e., the Cahn-Hilliard equation. Furthermore, they
discussed the mode coupling induced through the {\it irreversible} current.
Here, we show the {\it reversible} coupling can play a dominant role for
describing the QCD critical dynamics and that the dynamical universality class
does not necessarily belong to model H.Comment: 13 pages, the Curie principle is discussed in S.2, to appear in
J.Phys.
NNI-Form Quark Mass Matrix Expressed by the Observable Quantities
It is pointed out that the phase convention of the CKM matrix V affects
texture analysis of the quark mass matrices (M_u, M_d) when we try to describe
(M_u, M_d) by the observable quantities (quark masses and CKM matrix
parameters) only. This is demonstrated for a case of the non-Hermitian
Fritzsch-type mass matrix (tilde{M}_u, tilde{M}_d), which is a general
expression of quark mass matrix (M_u, M_d) and is described by twelve
parameters. We find that we can always choose a phase convention of V which
yields tilde{M}_{u32} = 0, so that the remaining ten parameters in (tilde{M}_u,
tilde{M}_d) can completely be expressed by the ten observable quantities.Comment: 11 pages (LaTeX); Title was change
Tribimaximal Neutrino Mixing and a Relation Between Neutrino- and Charged Lepton-Mass Spectra
Brannen has recently pointed out that the observed charged lepton masses
satisfy the relation m_e +m_\mu +m_\tau = {2/3}
(\sqrt{m_e}+\sqrt{m_\mu}+\sqrt{m_\tau})^2, while the observed neutrino masses
satisfy the relation m_{\nu 1} +m_{\nu 2} +m_{\nu 3} = {2/3} (-\sqrt{m_{\nu
1}}+\sqrt{m_{\nu 2}}+\sqrt{m_{\nu 3}})^2. It is discussed what neutrino Yukawa
interaction form is favorable if we take the fact pointed out by Brannen
seriously.Comment: 13 pages, presentation modifie
Microscopic Derivation of Causal Diffusion Equation using Projection Operator Method
We derive a coarse-grained equation of motion of a number density by applying
the projection operator method to a non-relativistic model. The derived
equation is an integrodifferential equation and contains the memory effect. The
equation is consistent with causality and the sum rule associated with the
number conservation in the low momentum limit, in contrast to usual acausal
diffusion equations given by using the Fick's law. After employing the Markov
approximation, we find that the equation has the similar form to the causal
diffusion equation. Our result suggests that current-current correlations are
not necessarily adequate as the definition of diffusion constants.Comment: 10 pages, 1 figure, Final version published in Phys. Rev.
Sweeping the Space of Admissible Quark Mass Matrices
We propose a new and efficient method of reconstructing quark mass matrices
from their eigenvalues and a complete set of mixing observables. By a
combination of the principle of NNI (nearest neighbour interaction) bases which
are known to cover the general case, and of the polar decomposition theorem
that allows to convert arbitrary nonsingular matrices to triangular form, we
achieve a parameterization where the remaining freedom is reduced to one
complex parameter. While this parameter runs through the domain bounded by a
circle with radius R determined by the up-quark masses around the origin in the
complex plane one sweeps the space of all mass matrices compatible with the
given set of data.Comment: 18 page
Spin Path Integrals and Generations
The spin of a free electron is stable but its position is not. Recent quantum
information research by G. Svetlichny, J. Tolar, and G. Chadzitaskos have shown
that the Feynman \emph{position} path integral can be mathematically defined as
a product of incompatible states; that is, as a product of mutually unbiased
bases (MUBs). Since the more common use of MUBs is in finite dimensional
Hilbert spaces, this raises the question "what happens when \emph{spin} path
integrals are computed over products of MUBs?" Such an assumption makes spin no
longer stable. We show that the usual spin-1/2 is obtained in the long-time
limit in three orthogonal solutions that we associate with the three elementary
particle generations. We give applications to the masses of the elementary
leptons.Comment: 20 pages, 2 figures, accepted at Foundations of Physic
Transport Coefficients of Non-Newtonian Fluid and Causal Dissipative Hydrodynamics
A new formula to calculate the transport coefficients of the causal
dissipative hydrodynamics is derived by using the projection operator method
(Mori-Zwanzig formalism) in [T. Koide, Phys. Rev. E75, 060103(R) (2007)]. This
is an extension of the Green-Kubo-Nakano (GKN) formula to the case of
non-Newtonian fluids, which is the essential factor to preserve the
relativistic causality in relativistic dissipative hydrodynamics. This formula
is the generalization of the GKN formula in the sense that it can reproduce the
GKN formula in a certain limit. In this work, we extend the previous work so as
to apply to more general situations.Comment: 15 pages, no figure. Discussions are added in the concluding remarks.
Accepted for publication in Phys. Rev.
Large Solar Neutrino Mixing in an Extended Zee Model
The Zee model, which employs the standard Higgs scalar () with its
duplicate () and a singly charged scalar (), can utilize two
global symmetries associated with the conservation of the numbers of and
, , where coincides
with the hypercharge while () is a new
conserved charge, which is identical to for the left-handed
leptons. Charged leptons turn out to have - and - mixing
masses, which are found to be crucial for the large solar neutrino mixing. In
an extended version of the Zee model with an extra triplet Higgs scalar (s),
neutrino oscillations are described by three steps: 1) the maximal atmospheric
mixing is induced by democratic mass terms supplied by with =2 that can
initiate the type II seesaw mechanism for the smallness of these masses; 2) the
maximal solar neutrino mixing is triggered by the creation of radiative masses
by with = 0; 3) the large solar neutrino mixing is finally induced by
a - mixing arising from the rotation of the radiative mass
terms as a result of the diagonalization that converts - and -
mixing masses into the electron mass.Comment: RevTex, 10 pages including one figure page, to be published in Int.
J. Mod. Phys. A (2002
Shear viscosity coefficient and relaxation time of causal dissipative hydrodynamics in QCD
The shear viscosity coefficient and the corresponding relaxation time for
causal dissipative hydrodynamics are calculated based on the microscopic
formula proposed in [T. Koide and T. Kodama, Phys. Rev. \textbf{E 78}, 051107
(2008)]. Here, the exact formula is transformed into a more compact form and
applied it to evaluate these transport coefficients in the chiral perturbation
theory and perturbative QCD. It is shown that in the leading order calculation,
the causal shear viscosity coefficient reduces to that of the ordinary
Green-Kubo-Nakano formula, and the relaxation time is related to
and pressure by a simple relationship, .Comment: 4 pages, 3 figures, errors of calcualtions were corrected, and some
rederences and discussions were added. Accepted version for publication in
PR
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