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arXiv:1708.01406 (hep-ph)
To be published in Physical Review D (American Physical Society)
Structure of Right-Handed Neutrino Mass Matrix
Recently, Nishiura and the author have proposed a unified quark-lepton mass
matrix model under a family symmetry U(3)$\times$U(3)$'$. The model can give
excellent parameter-fitting to the observed quark and neutrino data. The model
has a reasonable basis as far as the quark sector, but the form of the
right-handed neutrino mass matrix $M_R$ does not have a theoretical grand, that
is, it was nothing but a phenomenological assumption. In this paper, it is
pointed out that the form of $M_R$ is originated in structure of neutrino mass
matrix for $(\nu_i, N_\alpha)$ where $\nu_i$ ($i=1,2,3$) and $N_\alpha$
($\alpha=1,2,3$) are U(3)-family and U(3)$'$-family triplets, respectively.
arXiv:: 1701.06287 (hep-ph)
International Journal of Modern Physics A
(World Scientific) Vol.32, 1750085 (2017)
DOI:10.1142/S0217751X1750085
Flavon VEV Scales in U(3)$\times$U(3)$'$ Model
Yoshio Koide and Hiroyuki Nishiura
We have recently proposed a quark and lepton mass matrix model
based on U(3)$\times$U(3)$'$
family symmetry as the so-called
Yukawaon model, in which the U(3) symmetry is broken
by VEVs of flavons $(\Phi_f)_i^{\ \alpha}$ which are
$({\bf 3}, {\bf 3}^*)$ of U(3)$\times$U(3)$'$.
The model has successfully provided the unified
description of quark and lepton masses and mixings
by using the observed charged lepton masses as only family-number
dependent input parameters. However, our final goal is not only to give
well-satisfied fitting of quark and lepton masses and mixings, but
to investigate physics behind such a successful parameter fitting.
Therefore, our next concern is scales of VEVs of the flavons
because we have not paid attention to scales of flavons in
the previous study. In order to give consistency among the scales,
the previous flavon model is drastically changed together with economizing
number of the flavons, but with keeping previous phenomenological success.
We estimate that VEVs of flavons with $({\bf 8+1}, {\bf 1})$,
$({\bf 3}, {\bf 3}^*)$, and $({\bf 1}, {\bf 8+1})$ are of
the orders of $10$ TeV, $10^4$ TeV, and $10^7$ TeV, respectively.
Revised version of No.(4), 2016.
arXiv:1608.04514 (hep-ph)
Modern Physics Letters A (World Scientific) Vol.32, 1750062 (2017)
DOI:10.1042/S0217732317500626
Sumino's Cancellation Mechanism in an Anomaly-Free Model
An interesting family gauge boson (FGB) model (Model A) has been proposed by Sumino. The model can give FGBs with a considerably low energy scale in spite of the sever constraints form the observed $K^0$-$\bar{K}^0$ mixing and so on. An essential idea in Model A is in the so-called Sumino cancellation mechanism between QED and FGB diagrams. However, Model A is not anomaly free and, besides, it causes effective interactions with $\Delta N_{\rm family}=2$. In order to avoid these problems, a revised Sumino model with an inverted mass hierarchy (Model B) has proposed, but, in this time, it cannot satisfy the Sumino cancellation mechanism exactly. In this paper, we propose a revised version of Model B, where the model still keeps anomaly free, but it can exactly satisfy the Sumino mechanism. An effect of the revised model will be confirmed by observations $K^+ \rightarrow \pi^+ e^- \mu^+$ and $\mu^- N\rightarrow e^- N$.
Talk given at a mini-workshop on ``quarks, leptons and family gauge
bosons", Osaka University, Osaka, Japan, December 26-27, 2016.
arXiv:1701.01921 (hep-ph)
Sumino Model and My Personal View
There are two formulas for charged lepton mass relation: One is a formula (formula A) which was proposed based on a U(3) family model on 1982. The formula A will be satisfied only masses switched off all interactions except for U(3) family interactions. Other one (formula B) is an empirical formula which we have recognized after a report of the precise measurement of tau lepton mass, 1992. The formula B is excellently satisfied by pole masses of the charged leptons. However, this excellent agreement may be an accidental coincidence. Nevertheless, 2009, Sumino has paid attention to the formula B. He has proposed a family gauge boson model and thereby he has tried to understand why the formula B is so well satisfied with pole masses. In this talk, the following views are given: (i) What direction of flavor physics research is suggested by the formula A; (ii) How the Sumino model is misunderstood by people and what we should learn from his model; (iii) What is strategy of my recent work, U(3)$\times$U(3)$'$ model.
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