Endothermic Z'-Portal Dark Matter: LZ-LHC Complementarity

@misc{okada2026endothermic,
  title = {{Endothermic Z'-Portal Dark Matter: LZ-LHC Complementarity}},
  author = {Nobuchika Okada and Digesh Raut},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.21011},
  eprint = {2609.21011},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.21011},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - Endothermic Z'-Portal Dark Matter: LZ-LHC Complementarity
AU  - Nobuchika Okada
AU  - Digesh Raut
PY  - 2026
DA  - 2026/09/24
PB  - arXiv
DO  - 10.48550/arxiv.2609.21011
UR  - https://arxiv.org/abs/2609.21011
AB  - Motivated by the 2.6σ high-energy recoil event recently reported by the LUX-ZEPLIN (LZ) Collaboration, we consider an endothermic Z^′-portal Majorana dark matter framework and discuss the complementarity between the LZ event and LHC searches for a Z^′ resonance. As a concrete realization, we consider a gauged U(1) B−L extension of the Standard Model. The phenomenology of the framework is essentially controlled by two free parameters: the U(1) B−L gauge coupling g_BL and the Z^′ boson mass m_Z^′. For a fixed m_Z^′, the observed dark matter abundance requires the dark matter mass to be near the Z^′ resonance, m_DM ∼ m_Z^′/2, and sets a lower bound on g_BL. Complementarily, LHC searches for a Z^′ resonance set an upper bound on g_BL. The parameter space allowed by the dark matter abundance and LHC constraints can account for the recent LZ event. The synergy between future Z^′ resonance searches at the High-Luminosity LHC and the LZ experiment may provide a test of this framework.
ER  -