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Measurement of 𝑑-channel production of single top quarks and antiquarks in 𝑝𝑝 collisions at 13 TeV using the full ATLAS Run 2 data sample

Aad, G.; Abbott, B.; Abeling, K.; Abicht, N. J.; Abidi, S. H.; Aboulhorma, A.; Abramowicz, H.; Abreu, H.; Abulaiti, Y.; Abusleme Hoffman, A. C.; Acharya, B. S.; Adam Bourdarios, C.; 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.; Ait Tamlihat, M.; Aitbenchikh, B.; Aizenberg, I.; Akbiyik, M.; Γ…kesson, T. P. A.; Akimov, A. V.; Akiyama, D.; Akolkar, N. N.; Al Khoury, Konie

The production of single top quarks and top antiquarks via the 𝑑-channel exchange of a virtual π‘Š boson is measured in proton-proton collisions at a centre-of-mass energy of 13 TeV at the LHC using 140 fb⁻¹ of ATLAS data. The total cross-sections are determined to be 𝜎(π‘‘π‘ž) = 137=⁺⁸/β‚‹β‚ˆpb and 𝜎(π‘‘Μ„π‘ž) = 84⁺⁢/β‚‹β‚…pb for top-quark and top-antiquark production, respectively. The combined cross-section is found to be 𝜎(π‘‘π‘ž + π‘‘Μ„π‘ž) =221⁺¹³/₋₁₃pb and the cross-section ratio is 𝑅_𝑑=𝜎(π‘‘π‘ž)/𝜎(π‘‘Μ„π‘ž) =1.636⁺⁰˙⁰³⁢/β‚‹β‚€.₀₃₄.

The predictions at next-to-next-to-leading-order in quantum chromodynamics are in good agreement with these measurements. The predicted value of Rt using different sets of parton distribution functions is compared with the measured value, demonstrating the potential to further constrain the functions when using this result in global fits. The measured cross-sections are interpreted in an effective field theory approach, setting limits at the 95% confidence level on the strength of a four-quark operator and an operator coupling the third quark generation to the Higgs boson doublet: -0.37 < 𝐢 ³𝄒¹/_π‘„π‘ž/𝝠² < 0.06 and -0.87 < 𝐢 Β³/_πœ‘π‘„/𝝠² < 1.42.

The constraint |𝑉_𝑑𝑏| > 0.95 at the 95% confidence level is derived from the measured value of 𝜎(π‘‘π‘ž + π‘‘Μ„π‘ž), assuming that the π‘Šπ‘‘π‘ interaction is a left-handed weak coupling and that |𝑉_𝑑𝑏| ≫ |𝑉_𝑑𝑑|, |𝑉_𝑑𝑠|. In a more general approach, pairs of CKM matrix elements involving top quarks are simultaneously constrained, leading to confidence contours in the corresponding two-dimensional parameter spaces.

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Also Published In

Title
Journal of High Energy Physics
DOI
https://doi.org/10.1007/JHEP05(2024)305

More About This Work

Academic Units
Physics
Published Here
January 22, 2025

Notes

Hadron-Hadron Scattering

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