arXiv subjects

Zhen-hua Zhao

Publications and source records attributed to Zhen-hua Zhao.

41 records · Page 3Linked to original sources

arXiv2014

A Realization of Effective SUSY with Strong Unification

A natural model of realizing the effective supersymmetry is presented. Two sets of the Standard Model-like gauge group $G_1\times G_2$ are introduced, where $G_i=SU(3)_i\times SU(2)_i\times U(1)_i$, which break diagonally to the Standard Model gauge group at the energy scale $M \sim 10^7$ GeV. Gauge couplings in $G_1$ are assumed much larger than that in $G_2$. Gauge mediated supersymmetry breaking is adopted. The first two generations (third one) are charged only under $G_1$ ($G_2$). The effective supersymmetry spectrum is obtained. How to reproduce realistic Yukawa couplings is studied. Fine-tuning for an 126 GeV Higgs is much reduced by the large $A$ term due to direct Higgs-messenger interaction. Finally, $G_2$ is found to be a non-trivial realization of the strong unification scenario in which case we can predict $α_s(M_Z)$ without real unification

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arXiv2013

$θ_{13}$ and the Higgs mass from high scale supersymmetry

In the framework in which supersymmetry is used for understanding fermion masses rather than stabilizing the electroweak scale, we elaborate the phenomenological analysis for the neutrino physics. A relatively large $\sin{θ_{13}}$ is the natural result. The model further predicts vanishingly small CP violation in neutrino oscillations. And $θ_{23}$ is not necessarily maximal. While the high scale supersymmetry generically results in a Higgs mass of about 141 GeV, our model reduces this mass via introducing SU(2)$_L$ triplet fields which also contribute to neutrino masses.

hep-ph↗

arXiv2012

Understanding for flavor physics in the lepton sector

In this paper, we give a model for understanding flavor physics in the lepton sector--mass hierarchy among different generations and neutrino mixing pattern. The model is constructed in the framework of supersymmetry, with a family symmetry $S4*U(1)$. There are two right-handed neutrinos introduced for seesaw mechanism, while some standard model(SM) gauge group singlet fields are included which transforms non-trivially under family symmetry. In the model, each order of contributions are suppressed by $δ\sim 0.1$ compared to the previous one. In order to reproduce the mass hierarchy, $m_τ$ and $\sqrt{Δm_{atm}^2}$, $m_μ$ and $\sqrt{Δm_{sol}^2}$ are obtained at leading-order(LO) and next-to-leading-order(NLO) respectively, while electron can only get its mass through next-to-next-to-next-to-leading-order(NNNLO) contributions. For neutrino mixing angels, $θ_{12}, θ_{23}, θ_{13}$ are $45^\circ, 45^\circ, 0$ i.e. Bi-maximal mixing pattern as first approximation, while higher order contributions can make them consistent with experimental results. As corrections for $θ_{12}$ and $θ_{13}$ originate from the same contribution, there is a relation predicted for them $\sin{θ_{13}}=\displaystyle \frac{1-\tan{θ_{12}}}{1+\tan{θ_{12}}}$. Besides, deviation from $\displaystyle \fracπ{4}$ for $θ_{23}$ should have been as large as deviation from 0 for $θ_{13}$ if it were not the former is suppressed by a factor 4 compared to the latter.

hep-ph↗

arXiv2011

Realizing Tri-bimaximal Mixing in Minimal Seesaw Model with S4 Family Symmetry

In this paper, we realize the tri-bimaximal mixing in the lepton sector in the context of minimal seesaw in which only two right-handed neutrinos are introduced, with the discrete group $S4$ as the family symmetry. In order to constrain the form of superpotential, a $Z3$ symmetry is also introduced. In the model, the mass matrices for charged leptons and right-handed neutrinos are diagonal. The unitary matrix that diagonalizes the light Majorana neutrino mass matrix is exact tri-bimaximal at LO, and is corrected by small quantities of $\mathcal{O}(0.01)$ at NLO. The mechanism to get the particular scalar VEV alignments used is also presented. Phenomenologically, the mass spectrum is of normal hierarchy with $m_1=0$, and $\sum m_i$ and $|m_{ee}|$ are about $0.058 eV$ and $0.003 eV$ respectively.

hep-ph↗

arXiv2011

MINOS Anomaly as A Signal of Lorentz Violation

Recently, the MINOS collaboration reported an anomaly that the mass-squared difference and mixing angle of $\barν_μ$ $\leftrightarrow$ $\barν_τ$ are both different from that of $ν_μ$ $\leftrightarrow$ $ν_τ$. In this paper, based on the framework of neutrino oscillations, terms that break the Lorentz symmetry are used as perturbation to explain this anomaly and satisfactory results are got. Remarkably, some surprising conclusions, one of which is that in the high energy limit (hundreds of GeV) neutrino oscillation pattern will be independent of energy, are also arrived.

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