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(8) OU-HET-647/2009: November 13, 2009
International Journal of Modern Physics A, Vol.25. No.18 & 19,
3361-3673 (2010)
DOI: 10.1142/S0217751X10049694
How Can CP Violation in the Neutrino Sector
be Large in a 2-3 Symmetric Model?
Yoshio Koide and Hiroyuki Nishiura
Based on a neutrino mass matrix model in which a 2-3 symmetry
is only broken by a phase parameter, it is investigated how
the lepton mixing matrix can deviate from the so-called
tribimaximal mixing under a condition that $CP$ is maximally
violated.
International Journal of Modern Physics A, Vol.25, No.8,
1725-1738 (2010)
DOI: 10.1142/S0217751X10048068
Revise version of (2):
Title and presentation were changed: November 03, 2009
Can Massless and Light Yukawaons be Harmless?
In the so-called yukawaon model, where the effective Yukawa
coupling constants Y_f^{eff} (f=e,\nu,u,d) are given
by vacuum expectation values (VEVs) of gauge singlet scalars
(yukawaons) Y_f with 3\times 3 components, i.e.
Y_f^{eff}= y_f \langle Y_f\rangle/\Lambda,
massless (and light) scalars appear because a global
flavor symmetry is assumed.
In order to demonstrate whether such massless scalars in the
yukawaon model are harmless or not, yukawaon masses are
explicitly estimated, as an example, in the charged lepton
sector.
(6) OU-HET-633/2009: Augst 14, 2009
Physics Letters B, Vol.680, pages 76 - 80, (2009)
DOI: 10.1016/j.physletb.2009.08.038
Improved version of arXiv:0904.1644 [hep-ph]
Scenario was changed; also title was changed,
Yukawaon Model in the Quark Sectors and Nearly Tribimaximal Neutrino Mixing
For the purpose of deriving the observed nearly tribimaximal
neutrino mixing, a possible yukawaon model in the quark
sector is investigated.
Five observable quantities (2 up-quark mass ratios and
3 neutrino mixing parameters \sin^2 2\theta_{atm},
\tan^2\theta_{solar} and |U_{13}|) are
excellently fitted by two parameters (one in the up-quark sector
and another one in the right-handed Majorana neutrino sector).
arXiv:0906.3370 [hep-ph]: June 19, 2009
To appear in Physics Letters B.
DOI: 10.1016/j.physletb.2009.09.065
Final version: September 23, 2009
Charged Lepton Mass Spectrum and
Supersymmetric Yukawaon Model
On the basis of the so-called supersymmetric yukawaon model,
it is investigated what form of the superpotential W can
lead to the observed charged lepton mass spectrum.
A simple form of W can speculate reasonable values of
K(\mu)=(m_e +m_\mu + m_\tau)/(\sqrt{m_e} + \sqrt{m_\mu}
+ \sqrt{m_\tau})^2 and \kappa(\mu)=\sqrt{m_e m_\mu m_\tau}/
(\sqrt{m_e} + \sqrt{m_\mu}+ \sqrt{m_\tau})^3 at an
energy scale \mu=\Lambda.
arXiv:0904.1644 [hep-ph]: April 10, 2009
(Revised version: June 11, 2009 ;
Rresentation was drastically revised.)
For a further revised version, see (6) OU-HET-633/2009.
Yukawaons in the Quark Sectors
Based on the so-called ``yukawaon" model, where the effective
Yukawa coupling constants Y_f^{eff} (f=e,\nu,u,d) are
given by vacuum expectation values (VEVs) of gauge singlet
scalars (yukawaons) Y_f with 3\times 3 flavor components,
i.e. Y_f^{eff} = (y_f/\Lambda)\langle Y_f\rangle, it is
tried to describe VEV structures of the yukawaons Y_u and
Y_d in the up- and down-quark sectors in terms of a VEV
matrix \langle\Phi_e\rangle of a ur-yukawaon \Phi_e
whose eigenvalues are given by
\langle\Phi_e\rangle \propto {\rm diag}(\sqrt{m_e},
\sqrt{m_\mu},\sqrt{m_\tau}).
Thereby, not only the CKM mixing parameters but also neutrino
oscillation parameters are predicted under few adjustable
parameters.
Revised version of arXiv:0811.2839 [hep-ph]: April 22, 2009
Published in Physical Review D79, 093005-1 --6 (2009)
DOI: 10.1103/Phys.RevD.79.093005
Maximal CP Violation Hypothesis and
a Lepton Mixing Matrix
Yoshio Koide and Hiroyuki Nishiura
Maximal CP violation hypothesis is applied to
a simple lepton mixing matrix form U=V_{CKM}^\dagger U_{TB},
which has recently been speculated under an ansatz that
$U$ becomes an exact tribimaximal mixing U_{TB} in a limit
of the quark mixing matrix V_{CKM} \rightarrow {\bf 1}.
The prediction tan^2 \theta_{12} =1/2 in the case of
the exact tribimaximal mixing U=U_{TB} is considerably
spoiled in the speculated mixing U=V_{CKM}^\dagger U_{TB}.
However, the application of the hypothesis
to the lepton sector can again recover
the spoiled value to tan^2 \theta_{12} \simeq 1/2
if the original Kobayashi-Maskawa phase convention for
V_{CKM} is adopted.
arXiv:0902.4501 [hep-ph]: February 25, 2009
Revise version: May 08, 2009
For a further revised version, see (7) August 7, 2009.
Yukawaons in the Charged Lepton Sector
In the so-called yukawaon model, the effective Yukawa
coupling constants $Y_f^{eff}$ ($f=e,\nu,u,d$) are given
by vacuum expectation values (VEVs) of gauge singlet scalars
(yukawaons) $Y_f$ with $3\times 3$ components, i.e.
$Y_f^{eff}= y_f \langle Y_f\rangle/\Lambda$, where $\Lambda$
is an energy scale of the effective theory.
In order to reveal characteristic features of the model,
possible massless components of the yukawaons are
investigated in detail through an inspection in the
lepton sector.
Revised version of arXiv:0811.3470 [hep-ph]: January 21, 2009
Physical Review D, (2009) Vol.79, 033009-1 -- 5
DOI: 10.1103/Phys.RevD.79.033009
Charged Lepton Mass Relations in a Supersymmetric Yukawaon Model
According to an idea that effective Yukawa coupling
constants Y_f^{eff} are given vacuum expectation
values \langle Y_f\rangle of fields (``Yukawaons")
Y_f as Y_f^{eff}=y_f \langle Y_f\rangle/\Lambda,
a possible superpotential form in the charged lepton
sector under a U(3) [or O(3)] flavor symmetry
is investigated.
It is found that a specific form of the superpotential
can lead to an empirical charged lepton mass
relation without any adjustable parameters.
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