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Zhanpeng Hou

Publications and source records attributed to Zhanpeng Hou.

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The non-topological $Z^\prime$ string in the 331 model and its classical stability

We study the classical stability of a non-topological $Z^\prime$ string in the minimal 331 model, which arises from the maximal symmetry breaking pattern of an ${\rm SU}(6)$ toy model. Two Higgs triplets are introduced according to the emergent global symmetries in the fermionic sector of the ${\rm SU}(6)$ toy model, which will achieve the sequential symmetry breaking of ${\rm SU}(3)_c\otimes {\rm SU}(3)_W \otimes {\rm U}(1)_X\to {\rm SU}(3)_c\otimes {\rm SU}(2)_W \otimes {\rm U}(1)_Y$. By analyzing small perturbations around the string background and solving the coupled Helmholtz equations numerically, we find that the string is stable only near the semilocal limit of $\vartheta_S \approx \fracπ{2}$, even when Higgs self-couplings are tuned to minimize instabilities. This suggests that such non-topological strings are unlikely to exist in unified theories based on ${\rm SU}(N>5)$ Lie algebras.

hep-ph

Further study of the maximally symmetry breaking patterns in an ${\rm SU}(8)$ theory

An ${\rm SU}(8)$ theory was previously found to be the minimal simple gauge group where all three-generational Standard Model (SM) fermions can be nontrivially embedded. It is maximally broken into a subgroup of ${\rm SU}(8)\to {\cal G}_{441}\equiv {\rm SU}(4)_s \otimes {\rm SU}(4)_W \otimes {\rm U}(1)_{X_0}$ at the grand unified theory scale by the ${\rm SU}(8)$ adjoint Higgs field of $\mathbf{63_H}$. Gauge symmetries in the strong and the weak sectors are extended by one and two ranks, respectively. The sequential strong-weak-weak (SWW) symmetry breaking stages were found to generate the observed hierarchical SM quark/lepton masses as well as the Cabibbo-Kobayashi-Maskawa mixing pattern with the precise flavor identifications~[17, 20]. We further study the possible weak-strong-weak and weak-weak-strong symmetry breaking patterns, and compare with the results that we have obtained by following the SWW sequence. The two-loop renormalization group equations following both patterns are analyzed, where we cannot achieve the gauge coupling unification in the field theory framework. Through these analyses, we suggest the gauge coupling unification to be interpreted in the context of the affine Lie algebra.

hep-ph

The unification in an $\widehat {\mathfrak{s}\mathfrak{u}}(8)_{ k_U = 1}$ affine Lie algebra

A flavor-unified theory based on the simple Lie algebra of ${\mathfrak{s}\mathfrak{u}}(8)$ was previously proposed to generate the observed Standard Model quark/lepton mass hierarchies and the Cabibbo-Kobayashi-Maskawa mixing pattern due to their non-universal symmetry properties. A level-$1$ affine Lie algebra of $\widehat{ \mathfrak{s}\mathfrak{u} }(8)_{ k_U =1}$ with the ${\cal N}=1$ supersymmetric extension is found to unify three gauge couplings through the maximally symmetry breaking pattern.

hep-ph

The gauge coupling evolutions of an ${\rm SU}(8)$ theory with the maximally symmetry breaking pattern

We study the renormalizable group equations (RGEs) of the extended strong and weak gauge couplings in an ${\rm SU}(8)$ theory, where three-generational SM fermions are non-trivially embedded. This framework was previously found to generate the observed SM quark/lepton mass hierarchies and the Cabibbo-Kobayashi-Maskawa mixing pattern through its maximally breaking pattern. The field theoretical two-loop RGEs can not achieve the gauge coupling unification with the minimal setup, unless additional adjoint Higgs fields as well as the gravity-induced $d=5$ term to the ${\rm SU}(8)$ field strength term are included.

hep-ph