2026/07/08 by Marwa Telba
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle Detector Development and Performance #Particle physics theoretical and experimental studies #hep-ph
paper · pdf · doi:10.1142/s021773232650207x
openalex publication_date 2026/07/08 · openalex created_date 2026/07/09 · openalex updated_date 2026/07/25 · arxiv published 2026/08/04 · arxiv updated 2026/08/04
The trilinear Higgs self-coupling and di-Higgs production cross section are investigated in the semi-constrained NMSSM (scNMSSM) at large-λ / low-tanβ with full two-loop precision. A random scan of one million parameter points subject to theoretical, collider, flavor, and dark matter constraints yields 66 SM-like points with singlet fraction S132 < 0.05, all found in the mass range mh1 ∈ [122.0, 125.0]~GeV --- a feature that reflects an intrinsic property of the scNMSSM at large-λ / low-tanβ, where doublet-dominated configurations are kinematically confined below ∼125~GeV. The trilinear coupling ratio is found to be universally suppressed: κλ= 0.884--0.982, ⟨κλ⟩ = 0.944 ± 0.018. The non-resonant di-Higgs cross section at √(s) = 13.6~TeV lies in the range 30.3--36.9~fb (0.88--1.05 σ\rm SM), with the resonant contribution via gg → h3 → h1h1 negligible (≤ 0.004~fb). All predictions are consistent with current ATLAS+CMS di-Higgs upper limits and is expected to be probed at the HL-LHC. These results are discussed in the context of the electroweak phase transition, where the universal suppression of κλ is qualitatively consistent with a modified Higgs potential that could support a strengthened first-order transition. A quantitative determination of the phase transition strength via finite-temperature analysis is left for future work.