Speaker
Description
A search for off-shell production of the Higgs boson using 139 fb−1 of 𝑝𝑝 collision data at √𝑠 = 13 TeV collected by the ATLAS detector at the Large Hadron Collider. The observable signature is a pair of on-shell 𝑍 bosons, with contributions both from the virtual Higgs boson and interference with other processes, and the two decay final states, 𝑍 𝑍 → 4ℓ and 𝑍 𝑍 → 2ℓ2𝜈 with ℓ = 𝑒 or 𝜇. The background-only hypothesis is rejected with an observed (expected) significance of 3.2 (2.4) 𝜎, which marks the experimental evidence of off-shell Higgs production. The observed (expected) upper limit on the signal strength, defined as the event yield normalised to the Standard Model prediction is 2.3 (2.4) at a 95% confidence level, which restricts the total width of the Higgs boson to be less than 9.7 (10.2) MeV at the same confidence level. Besides, the off-shell Higgs (220 GeV < mH < 2000 GeV) provides a pivotal window to search for BSM hints. The corresponding EFT interpretations for Higgs-gluon and Higgs-top quark interactions are also provided.
| Submitted on behalf of a Collaboration? | Yes |
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