Hunting for Long-Lived ALPs in Top Events via Displaced Dielectron Pairs at the LHC
Abstract
A generator-level sensitivity study is presented for long-lived axion-like particles (ALPs) produced in association with top-quark pairs and decaying to displaced electron-positron pairs at the CERN LHC. The prompt objects from the top quark-antiquark system provide independent handles for event selection, allowing the event to be selected independently of the displaced electron pair and extending the search to ALP masses below the dimuon threshold. A search strategy motivated by the CMS detector is developed for ALP masses between 17 MeV and 10 GeV and proper decay lengths between 0.1 mm and 1 m. Expected upper limits at 95% confidence level are computed for σ(pp→ tt̅ a)×ℬ(a→ e+e-) as a function of the ALP mass and proper decay length. In the most sensitive region of the parameter space considered, values of the cross section times branching fraction of order 10−3 pb can be probed for an integrated luminosity of 500 fb−1 at √s=13 TeV. These projections do not include detector-level displaced-electron reconstruction or instrumental backgrounds.
Related
- Displaced Signals from Long-lived Particles in Neutrinoless Double Beta Decay
- Nested Disappearing-Track plus Displaced-Vertex Topology at the HL-LHC: A Dual Long-Lived-Particle Signature of the Scotogenic Model
- Nested disappearing-track plus displaced-vertex topology at the HL-LHC: a dual long-lived-particle signature of the scotogenic model
- Long-lived Laughlin pairs in a depleted quantum Hall edge channel
- Performance of the MPD experiment in dielectron measurements at NICA
BibTeX
@misc{alimena2026hunting,
title = {{Hunting for Long-Lived ALPs in Top Events via Displaced Dielectron Pairs at the LHC}},
author = {Juliette Alimena and Freya Blekman and Cesare Cazzaniga and Xabier Cid Vidal and Jeremi Niedziela and Lovisa Rygaard and Rosalia Soto Rey},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.38932},
eprint = {2610.38932},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.38932},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Hunting for Long-Lived ALPs in Top Events via Displaced Dielectron Pairs at the LHC
AU - Juliette Alimena
AU - Freya Blekman
AU - Cesare Cazzaniga
AU - Xabier Cid Vidal
AU - Jeremi Niedziela
AU - Lovisa Rygaard
AU - Rosalia Soto Rey
PY - 2026
DA - 2026/10/28
PB - arXiv
DO - 10.48550/arxiv.2610.38932
UR - https://arxiv.org/abs/2610.38932
AB - A generator-level sensitivity study is presented for long-lived axion-like particles (ALPs) produced in association with top-quark pairs and decaying to displaced electron-positron pairs at the CERN LHC. The prompt objects from the top quark-antiquark system provide independent handles for event selection, allowing the event to be selected independently of the displaced electron pair and extending the search to ALP masses below the dimuon threshold. A search strategy motivated by the CMS detector is developed for ALP masses between 17 MeV and 10 GeV and proper decay lengths between 0.1 mm and 1 m. Expected upper limits at 95% confidence level are computed for σ(pp→ tt̅ a)×ℬ(a→ e^+e^-) as a function of the ALP mass and proper decay length. In the most sensitive region of the parameter space considered, values of the cross section times branching fraction of order 10^−3 pb can be probed for an integrated luminosity of 500 fb^−1 at √s=13 TeV. These projections do not include detector-level displaced-electron reconstruction or instrumental backgrounds.
SN - 2331-8422
ER -