15817 10.1140/epjc/s10052-026-15817-7 643 54 Higgs boson decays

h \to Z γ

and

h \to m_{V} Z

in the

U {(1)}_{X}

VLFM Regular Article - Theoretical Physics Theoretical Physics 1 19 2026 5 8 2026 1 19 2026 5 8 2026 6 14 2026 6 14 Natural Science Foundation of Hebei Province A2023201040 The Author(s) 2026 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ . Funded by SCOAP3. 10052 86 86 6 6 Rong-Zhi Sun Shu-Min Zhao zhaosm@hbu.edu.cn Yue-Tong Liu Xing-Xing Dong dongxx@hbu.edu.cn https://ror.org/01p884a79 grid.256885.4 0000 0004 1791 4722 Department of Physics Hebei University Baoding 071002 China https://ror.org/01p884a79 grid.256885.4 0000 0004 1791 4722 Hebei Key Laboratory of High-precision Computation and Application of Quantum Field Theory Baoding 071002 China Hebei Research Center of the Basic Discipline for Computational Physics Baoding 071002 China https://ror.org/01c27hj86 grid.9983.b 0000 0001 2181 4263 Departamento de Fisica and CFTP, Instituto Superior Técnico, Universidade de Lisboa Av. Rovisco Pais 1 1049-001 Lisbon Portugal Abstract We study the Higgs boson decays

h \to Z γ

and

h \to m_{V} Z

in a model with vectorlike fermions and

U {(1)}_{X}

symmetry (

U {(1)}_{X}

VLFM), where

m_{V}

is a vector meson (

ρ, ω, ϕ, J / ψ, Υ

). The exotic Yukawa interactions in this model generate mixing between Standard Model (SM) fermions and vectorlike fermions, and this mixing affects the Higgs boson mass and Higgs couplings. The corrections to the CP-even and CP-odd

h γ Z

couplings come from loop diagrams that involve the new particles, and these corrections have a clear impact on the decay rates of

h \to Z γ

and

h \to m_{V} Z

. In suitable regions of the parameter space, the model can produce non-negligible deviations in

Γ_{NP} (h \to Z γ) / Γ_{SM} (h \to Z γ)

and

Γ_{NP} (h \to m_{V} Z) / Γ_{SM} (h \to m_{V} Z)

, providing possible signals of new physics (NP) beyond the SM.