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

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Peer-reviewed

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Authors

Aad, G 
Abbott, B 
Abeling, K 
Abicht, NJ 
Abidi, SH 

Abstract

jats:titleAjats:scbstract</jats:sc> </jats:title>jats:pThe production of single top quarks and top antiquarks via the jats:italict</jats:italic>-channel exchange of a virtual jats:italicW</jats:italic> boson is measured in proton-proton collisions at a centre-of-mass energy of 13 TeV at the LHC using 140 fbjats:supjats:italic−</jats:italic>1</jats:sup> of ATLAS data. The total cross-sections are determined to be jats:inline-formulajats:alternativesjats:tex-math$$ \sigma (tq)={137}{-8}^{+8} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> mml:miσ</mml:mi> mml:mfenced mml:mitq</mml:mi> </mml:mfenced> mml:mo=</mml:mo> mml:msubsup mml:mn137</mml:mn> mml:mrow mml:mo−</mml:mo> mml:mn8</mml:mn> </mml:mrow> mml:mrow mml:mo+</mml:mo> mml:mn8</mml:mn> </mml:mrow> </mml:msubsup> </mml:math></jats:alternatives></jats:inline-formula> pb and jats:inline-formulajats:alternativesjats:tex-math$$ \sigma \left(\overline{t}q\right)={84}{-5}^{+6} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> mml:miσ</mml:mi> mml:mfenced mml:mrow mml:mover mml:mit</mml:mi> mml:mo¯</mml:mo> </mml:mover> mml:miq</mml:mi> </mml:mrow> </mml:mfenced> mml:mo=</mml:mo> mml:msubsup mml:mn84</mml:mn> mml:mrow mml:mo−</mml:mo> mml:mn5</mml:mn> </mml:mrow> mml:mrow mml:mo+</mml:mo> mml:mn6</mml:mn> </mml:mrow> </mml:msubsup> </mml:math></jats:alternatives></jats:inline-formula> pb for top-quark and top-antiquark production, respectively. The combined cross-section is found to be jats:inline-formulajats:alternativesjats:tex-math$$ \sigma \left( tq+\overline{t}q\right)={221}{-13}^{+13} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> mml:miσ</mml:mi> mml:mfenced mml:mrow mml:mitq</mml:mi> mml:mo+</mml:mo> mml:mover mml:mit</mml:mi> mml:mo¯</mml:mo> </mml:mover> mml:miq</mml:mi> </mml:mrow> </mml:mfenced> mml:mo=</mml:mo> mml:msubsup mml:mn221</mml:mn> mml:mrow mml:mo−</mml:mo> mml:mn13</mml:mn> </mml:mrow> mml:mrow mml:mo+</mml:mo> mml:mn13</mml:mn> </mml:mrow> </mml:msubsup> </mml:math></jats:alternatives></jats:inline-formula> pb and the cross-section ratio is jats:inline-formulajats:alternativesjats:tex-math$$ {R}t=\sigma (tq)/\sigma \left(\overline{t}q\right)={1.636}{-0.034}^{+0.036} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> mml:msub mml:miR</mml:mi> mml:mit</mml:mi> </mml:msub> mml:mo=</mml:mo> mml:miσ</mml:mi> mml:mfenced mml:mitq</mml:mi> </mml:mfenced> mml:mo/</mml:mo> mml:miσ</mml:mi> mml:mfenced mml:mrow mml:mover mml:mit</mml:mi> mml:mo¯</mml:mo> </mml:mover> mml:miq</mml:mi> </mml:mrow> </mml:mfenced> mml:mo=</mml:mo> mml:msubsup mml:mn1.636</mml:mn> mml:mrow mml:mo−</mml:mo> mml:mn0.034</mml:mn> </mml:mrow> mml:mrow mml:mo+</mml:mo> mml:mn0.036</mml:mn> </mml:mrow> </mml:msubsup> </mml:math></jats:alternatives></jats:inline-formula>. The predictions at next-to-next-to-leading-order in quantum chromodynamics are in good agreement with these measurements. The predicted value of jats:italicR</jats:italic>jats:subjats:italict</jats:italic></jats:sub> 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: jats:inline-formulajats:alternativesjats:tex-math$$ -0.37<{C}{Qq}^{3,1}/{\Lambda}^2<0.06 $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> mml:mo−</mml:mo> mml:mn0.37</mml:mn> mml:mo<</mml:mo> mml:msubsup mml:miC</mml:mi> mml:miQq</mml:mi> mml:mrow mml:mn3</mml:mn> mml:mo,</mml:mo> mml:mn1</mml:mn> </mml:mrow> </mml:msubsup> mml:mo/</mml:mo> mml:msup mml:miΛ</mml:mi> mml:mn2</mml:mn> </mml:msup> mml:mo<</mml:mo> mml:mn0.06</mml:mn> </mml:math></jats:alternatives></jats:inline-formula> and jats:inline-formulajats:alternativesjats:tex-math$$ -0.87<{C}_{\phi Q}^3/{\Lambda}^2<1.42 $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> mml:mo−</mml:mo> mml:mn0.87</mml:mn> mml:mo<</mml:mo> mml:msubsup mml:miC</mml:mi> mml:miϕQ</mml:mi> mml:mn3</mml:mn> </mml:msubsup> mml:mo/</mml:mo> mml:msup mml:miΛ</mml:mi> mml:mn2</mml:mn> </mml:msup> mml:mo<</mml:mo> mml:mn1.42</mml:mn> </mml:math></jats:alternatives></jats:inline-formula>. The constraint jats:italic|V</jats:italic>jats:subjats:italictb</jats:italic></jats:sub>jats:italic|</jats:italic> > 0.95 at the 95% confidence level is derived from the measured value of jats:inline-formulajats:alternativesjats:tex-math$$ \sigma \left( tq+\overline{t}q\right) $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> mml:miσ</mml:mi> mml:mfenced mml:mrow mml:mitq</mml:mi> mml:mo+</mml:mo> mml:mover mml:mit</mml:mi> mml:mo¯</mml:mo> </mml:mover> mml:miq</mml:mi> </mml:mrow> </mml:mfenced> </mml:math></jats:alternatives></jats:inline-formula>, assuming that the jats:italicWtb</jats:italic> interaction is a left-handed weak coupling and that |jats:italicV</jats:italic>jats:subjats:italictb</jats:italic></jats:sub>| ≫ |jats:italicV</jats:italic>jats:subjats:italictd</jats:italic></jats:sub>|, |jats:italicV</jats:italic>jats:subjats:italicts</jats:italic></jats:sub>|. 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.</jats:p>

Description

Keywords

5106 Nuclear and Plasma Physics, 5107 Particle and High Energy Physics, 51 Physical Sciences

Journal Title

Journal of High Energy Physics

Conference Name

Journal ISSN

1126-6708
1029-8479

Volume Title

2024

Publisher

Springer Science and Business Media LLC