Search for Long-Lived Dark Photons from Dark Radiation at the LHC

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Chen, Chuan-Ren, Tran, Van Que
Format: Preprint
Published: 2026
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866910190949892096
author Chen, Chuan-Ren
Tran, Van Que
author_facet Chen, Chuan-Ren
Tran, Van Que
contents We investigate a novel production mechanism for long-lived dark photons at the LHC, arising from dark radiation emitted from $χ$ in $Z\to\barχχ$ decays, where $χ$ is a fermionic dark matter candidate. The effective $Zχχ$ coupling is generated radiatively through one-loop diagrams involving the top quark and a new colored scalar. We show that dark photons produced via this dark radiation channel can dominate over the conventional sources-meson decays and proton bremsstrahlung-across wide regions of parameter space, particularly for small kinetic mixing and dark photon masses well above the GeV scale. Using this enhanced production mechanism, we analyze the sensitivity of dedicated long-lived particle detectors, including FASER2, FACET, and MATHUSLA. We find that these experiments can significantly surpass existing bounds, probing regions of dark photon parameter space consistent with the observed dark matter relic abundance and inaccessible in conventional dark photon scenarios.
format Preprint
id arxiv_https___arxiv_org_abs_2605_03427
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Search for Long-Lived Dark Photons from Dark Radiation at the LHC
Chen, Chuan-Ren
Tran, Van Que
High Energy Physics - Phenomenology
We investigate a novel production mechanism for long-lived dark photons at the LHC, arising from dark radiation emitted from $χ$ in $Z\to\barχχ$ decays, where $χ$ is a fermionic dark matter candidate. The effective $Zχχ$ coupling is generated radiatively through one-loop diagrams involving the top quark and a new colored scalar. We show that dark photons produced via this dark radiation channel can dominate over the conventional sources-meson decays and proton bremsstrahlung-across wide regions of parameter space, particularly for small kinetic mixing and dark photon masses well above the GeV scale. Using this enhanced production mechanism, we analyze the sensitivity of dedicated long-lived particle detectors, including FASER2, FACET, and MATHUSLA. We find that these experiments can significantly surpass existing bounds, probing regions of dark photon parameter space consistent with the observed dark matter relic abundance and inaccessible in conventional dark photon scenarios.
title Search for Long-Lived Dark Photons from Dark Radiation at the LHC
topic High Energy Physics - Phenomenology
url https://arxiv.org/abs/2605.03427