Dark Diffraction at LZ from a Screened Neutral Composite Baryon
Abstract
The LUX-ZEPLIN (LZ) experiment recently reported a nuclear-recoil-like candidate at ER=248±23stat±23sys keV. We show that such an energetic recoil can arise from the elastic form factor of composite dark matter, without invoking an inelastic mass splitting or a boosted population. A neutral baryon of N dark quarks can have a charge form factor that is suppressed at low momentum transfer but recovers at higher momentum transfer, providing a momentum-space band-pass filter. Modeling the form factor with one Gaussian per charged constituent species, we prove that two terms cannot produce a hard recoil spectrum and find that three yield too few events in the LZ signal window, while four suffice. A confining SU(4)D× U(1)D gauge theory provides a concrete realization through a neutral bosonic baryon made of four dark quarks. For a 200 GeV benchmark normalized to one accepted event, we predict approximately 1.5 true recoils beyond the current LZ region of interest. The form factor also produces diffraction nodes at fixed momentum transfers, placing them at recoil energies that scale as 1/mA across target nuclei.
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BibTeX
@misc{jung2026dark,
title = {{Dark Diffraction at LZ from a Screened Neutral Composite Baryon}},
author = {Hyunjoo Jung and Seong Chan Park},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.25723},
eprint = {2609.25723},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.25723},
}
RIS
TY - UNPB
TI - Dark Diffraction at LZ from a Screened Neutral Composite Baryon
AU - Hyunjoo Jung
AU - Seong Chan Park
PY - 2026
DA - 2026/09/22
PB - arXiv
DO - 10.48550/arxiv.2609.25723
UR - https://arxiv.org/abs/2609.25723
AB - The LUX-ZEPLIN (LZ) experiment recently reported a nuclear-recoil-like candidate at E_R=248±23_stat±23_sys keV. We show that such an energetic recoil can arise from the elastic form factor of composite dark matter, without invoking an inelastic mass splitting or a boosted population. A neutral baryon of N dark quarks can have a charge form factor that is suppressed at low momentum transfer but recovers at higher momentum transfer, providing a momentum-space band-pass filter. Modeling the form factor with one Gaussian per charged constituent species, we prove that two terms cannot produce a hard recoil spectrum and find that three yield too few events in the LZ signal window, while four suffice. A confining SU(4)_D× U(1)_D gauge theory provides a concrete realization through a neutral bosonic baryon made of four dark quarks. For a 200 GeV benchmark normalized to one accepted event, we predict approximately 1.5 true recoils beyond the current LZ region of interest. The form factor also produces diffraction nodes at fixed momentum transfers, placing them at recoil energies that scale as 1/m_A across target nuclei.
ER -