Quantum probes of invisible particles in top-quark pair production at the LHC
Abstract
Top-quark pair production at the LHC provides a bipartite spin system whose correlations are imprinted in the angular distributions of the decay products and can be studied with quantum-information tools. We investigate whether this spin structure can be used to probe invisible new physics in pp→ tt̅+X, where X is a spin-0 or spin-1 mediator motivated by top-philic simplified dark-matter models. Focusing on the dileptonic channel at the High-Luminosity LHC, we compare the sensitivity of the inclusive event yield, the visible invariant-mass distribution, an event-level estimator of the entanglement marker D, and the fiducial spin correlation 𝒟 measured as a function of the visible invariant mass. We find that observables retaining spin information improve the expected exclusion sensitivity with respect to rate and kinematic information alone, with 𝒟(Mtt̅vis) providing the strongest reach for both mediator spins. The same observables also enhance the discrimination between scalar and pseudoscalar couplings of the spin-zero mediator, with 𝒟(Mtt̅vis) again providing the strongest sensitivity, particularly at larger mediator masses. These results show that quantum-information-motivated observables of the tt̅ system can be efficient tools to probe both the presence of invisible new physics and the structure of its couplings to top quarks.
Related
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- Electric Dipole Moments as Precision Probes of CP-Violating Top-Quark Interactions in SMEFT
- Exact flavor conservation at the quark level in causal clusters: strange particles, protons and light nuclei in small collision systems
- Multiboson production at multi-TeV lepton colliders as complementary probes to rare Higgs decays
- Two-loop QCD contribution to the quark-initiated production of a top-antitop quark pair and a Higgs boson at the LHC
BibTeX
@misc{belmonte2026quantum,
title = {{Quantum probes of invisible particles in top-quark pair production at the LHC}},
author = {Blanca Belmonte and Diego Blas and Alba Cervera-Lierta and Francesco Montagno},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2609.31425},
eprint = {2609.31425},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.31425},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Quantum probes of invisible particles in top-quark pair production at the LHC
AU - Blanca Belmonte
AU - Diego Blas
AU - Alba Cervera-Lierta
AU - Francesco Montagno
PY - 2026
DA - 2026/10/07
PB - arXiv
DO - 10.48550/arxiv.2609.31425
UR - https://arxiv.org/abs/2609.31425
AB - Top-quark pair production at the LHC provides a bipartite spin system whose correlations are imprinted in the angular distributions of the decay products and can be studied with quantum-information tools. We investigate whether this spin structure can be used to probe invisible new physics in pp→ tt̅+X, where X is a spin-0 or spin-1 mediator motivated by top-philic simplified dark-matter models. Focusing on the dileptonic channel at the High-Luminosity LHC, we compare the sensitivity of the inclusive event yield, the visible invariant-mass distribution, an event-level estimator of the entanglement marker D, and the fiducial spin correlation 𝒟 measured as a function of the visible invariant mass. We find that observables retaining spin information improve the expected exclusion sensitivity with respect to rate and kinematic information alone, with 𝒟(M_tt̅^vis) providing the strongest reach for both mediator spins. The same observables also enhance the discrimination between scalar and pseudoscalar couplings of the spin-zero mediator, with 𝒟(M_tt̅^vis) again providing the strongest sensitivity, particularly at larger mediator masses. These results show that quantum-information-motivated observables of the tt̅ system can be efficient tools to probe both the presence of invisible new physics and the structure of its couplings to top quarks.
ER -