Search for the production of a Higgs boson in association with a single top quark in pp collisions at s=13 TeV with the ATLAS detector


Aad G., Aakvaag E., Abbott B., Abdelhameed S., Abeling K., Abicht N., ...More

Journal of High Energy Physics, vol.2025, no.10, 2025 (SCI-Expanded, Scopus) identifier identifier

  • Publication Type: Article / Article
  • Volume: 2025 Issue: 10
  • Publication Date: 2025
  • Doi Number: 10.1007/jhep10(2025)093
  • Journal Name: Journal of High Energy Physics
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, INSPEC, MathSciNet, zbMATH, Directory of Open Access Journals, Nature Index
  • Keywords: Hadron-Hadron Scattering
  • Istanbul University Affiliated: Yes

Abstract

A search for the production of a Higgs boson in association with a single top quark, tH, is presented. The analysis uses proton-proton collision data corresponding to an integrated luminosity of 140 fb−1 at a centre-of-mass energy of 13 TeV, collected by the ATLAS detector at the LHC. The search targets Higgs-boson decays into bb¯, WW*, ZZ*, and ττ, accompanied by an isolated lepton (electron or muon) from the top-quark decay. Multivariate techniques are employed to enhance the separation between signal and background processes. The observed signal strength, μtH, defined as the ratio between the measured cross-section and the predicted Standard Model value, is μtH = 8.1 ± 2.6 (stat.) ± 2.0 (syst.). The significance of the observed (expected) signal above the background-only expectation is 2.8 (0.4) standard deviations. The corresponding observed (expected) upper limit at the 95% confidence level on the tH cross-section is found to be 13.9 (6.1) times the value predicted by the Standard Model. An interpretation with an inverted sign of the top-quark Yukawa coupling is performed, and the signal strength and corresponding limit are reported.