2024 Articles

Measurement of the 𝐻 → 𝛾𝛾 and 𝐻 → 𝑍𝑍* → 4ℓ cross-sections in 𝑝𝑝 collisions at √𝑠 = 13.6TeV with the ATLAS detector

Aad, G.; Abbott, B.; Abeling, K.; Abicht, N. J.; Abidi, S. H.; Aboulhorma, A.; Abramowicz, H.; Abreu, H.; Abulaiti, Y.; Acharya, B. S.; Bourdarios, C. A.; Adamczyk, L.; Adamek, L.; Addepalli, S. V.; Addison, M. J.; Adelman, J.; Adiguzel, A.; Adye, T.; Affolder, A. A.; Afik, Y.; Agaras, M. N.; Agarwala, J.; Aggarwal, A.; Agheorghiesei, C.; Ahmad, A.; Ahmadov, F.; Ahmed, W. S.; Ahuja, S.; Ai, X.; Aielli, G.; Aikot, A.; Tamlihat, M. A.; Aitbenchikh, B.; Aizenberg, I.; Akbiyik, M.; Åkesson, T. P. A.; Akimov, A. V.; Akiyama, D.; Akolkar, N. N.; Khoury, K. A.

The inclusive Higgs boson production cross-section is measured in the di-photon and the 𝑍𝑍* → 4ℓ decay channels using 31.4 and 29.0 fb⁻¹ of 𝑝𝑝 collision data respectively, collected with the ATLAS detector at a centre-of-mass energy of √𝑠 = 13.6TeV. To reduce the model dependence, the measurement in each channel is restricted to a particle-level phase space that closely matches the channel’s detector-level kinematic selection, and it is corrected for detector effects. These measured fiducial cross-sections are σ_fid,𝛾𝛾 = 76⁺¹⁴/₋₁₃ fb, and σ_fid,4ℓ = 2.80 ± 0.74 fb, in agreement with the corresponding Standard Model predictions of 67.6 ± 3.7 fb and 3.67 ± 0.19 fb.

Assuming Standard Model acceptances and branching fractions for the two channels, the fiducial measurements are extrapolated to the full phase space yielding total cross-sections of σ (𝑝𝑝 → 𝐻) = 67⁺¹²/₋₁₁ pb and 46 ± 12 pb at 13.6 TeV from the di-photon and 𝑍𝑍*→ 4ℓ measurements respectively. The two measurements are combined into a total cross-section measurement of σ (𝑝𝑝 → 𝐻)= 58.2 ± 8.7 pb, to be compared with the Standard Model prediction of σ (𝑝𝑝 → 𝐻)_SM = 59.9 ± 2.6 pb.