Fermiophobic Z' Bosons in 3-4-1 Models: Classification and Collider Constraints
Abstract
We investigate the fermion spectra and collider phenomenology of models based on the SU(3)C ⊗ SU(4)L ⊗ U(1)X gauge symmetry, focusing on two realizations of the electric charge operator characterized by b=c=1 and b=1, c=−2. For each configuration, we classify anomaly-free fermion sets and identify five minimal spectra with at least three SM-like quark and lepton families for each configuration, distinguishing algebraically irreducible structures from reducible spectra that remain minimal under the three-family requirement. We derive the chiral couplings of the additional neutral gauge boson Z' to Standard Model fermions and show that distinct anomaly-free fermion spectra can lead to identical low-energy neutral-current interactions. We then investigate the corresponding collider constraints using the ATLAS dilepton resonance search at √s=13 TeV with an integrated luminosity of 139 fb−1, assuming negligible Z−Z' mixing and kinematically inaccessible exotic fermions. A particularly interesting result emerges for the b=c=1 configuration, where all Z' couplings to Standard Model fermions are proportional to sinψ, with ψ denoting the additional neutral gauge-boson mixing angle. Consequently, these couplings vanish simultaneously at ψ=nπ, giving rise to a fermiophobic limit in which conventional Drell-Yan dilepton constraints disappear. In contrast, the b=1, c=−2 configuration does not exhibit a universal fermiophobic limit. Our results demonstrate that collider constraints on additional neutral gauge bosons depend sensitively on the fermion embeddings and neutral gauge-boson mixing structure, and suggest the possibility of comparatively light Z' bosons in suitable realizations of extended electroweak gauge theories.
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BibTeX
@misc{suarez2026fermiophobic,
title = {{Fermiophobic Z' Bosons in 3-4-1 Models: Classification and Collider Constraints}},
author = {Eduard Suarez and Yithsbey Giraldo and Eduardo Rojas},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.33805},
eprint = {2610.33805},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.33805},
}
RIS
TY - UNPB
TI - Fermiophobic Z' Bosons in 3-4-1 Models: Classification and Collider Constraints
AU - Eduard Suarez
AU - Yithsbey Giraldo
AU - Eduardo Rojas
PY - 2026
DA - 2026/10/24
PB - arXiv
DO - 10.48550/arxiv.2610.33805
UR - https://arxiv.org/abs/2610.33805
AB - We investigate the fermion spectra and collider phenomenology of models based on the SU(3)_C ⊗ SU(4)_L ⊗ U(1)_X gauge symmetry, focusing on two realizations of the electric charge operator characterized by b=c=1 and b=1, c=−2. For each configuration, we classify anomaly-free fermion sets and identify five minimal spectra with at least three SM-like quark and lepton families for each configuration, distinguishing algebraically irreducible structures from reducible spectra that remain minimal under the three-family requirement. We derive the chiral couplings of the additional neutral gauge boson Z' to Standard Model fermions and show that distinct anomaly-free fermion spectra can lead to identical low-energy neutral-current interactions. We then investigate the corresponding collider constraints using the ATLAS dilepton resonance search at √s=13 TeV with an integrated luminosity of 139 fb^−1, assuming negligible Z−Z' mixing and kinematically inaccessible exotic fermions. A particularly interesting result emerges for the b=c=1 configuration, where all Z' couplings to Standard Model fermions are proportional to sinψ, with ψ denoting the additional neutral gauge-boson mixing angle. Consequently, these couplings vanish simultaneously at ψ=nπ, giving rise to a fermiophobic limit in which conventional Drell-Yan dilepton constraints disappear. In contrast, the b=1, c=−2 configuration does not exhibit a universal fermiophobic limit. Our results demonstrate that collider constraints on additional neutral gauge bosons depend sensitively on the fermion embeddings and neutral gauge-boson mixing structure, and suggest the possibility of comparatively light Z' bosons in suitable realizations of extended electroweak gauge theories.
ER -