Physicists nail rare single-top-quark production at new energy level
Researchers at CERN's Large Hadron Collider have precisely measured how often individual top quarks form in high-energy collisions, a measurement that tests fundamental physics models and validates detector capabilities. The finding strengthens confidence in the Standard Model of particle physics, which underpins our understanding of matter and energy.
Originaltitel: Measurement of <em>t</em>-channel single-top-quark production in <em>pp</em> collisions at √<em>s</em>=5.02 TeV with the ATLAS detector
<p>The observation of the electroweak production of single-top-quarks is made using 255 pb<sup>-1</sup> of proton-proton collision data recorded at √s = 5.02 TeV with the ATLAS detector at the Large Hadron Collider. An event selection is used to identify single-top-quark candidates arising from..-channel production with the top quark decaying semi-leptonically. Events passing the selection are then used to measure the inclusive cross-section for the combined production of single-top-quarks and antiquarks, σ(tq + t<over bar>q), and the ratio R<sub>t</sub> between these two. They are measured to be σ(tq + t<over bar>q = 27.1<sub>-4.1</sub><sup>+4.4</sup>(stat.)<sub>-3.7</sub><sup>+4.4</sup>(syst.) pb and R<sub>t</sub> = 2.73<sub>-0.82</sub><sup>+1.43</sup>(stat.)<sub>-0.29</sub><sup>+1.01</sup>)(syst.). The individual single-top-quark (tq) and single-top-antiquark (t<over bar>q) production cross-sections are measured to be σ(tq) = 19.8<sub>-3.1</sub><sup>+3.9</sup>(stat.)<sub>-2.2</sub><sup>+2.9</sup>(syst.) pb and σ(t<over bar>q) = 7.3<sub>-2.1</sub><sup>+3.2</sup>)(stat.)<sub>-1.5</sub><sup>+2.8</sup>)(syst.) pb. All measurements are in good agreement with the Standard Model predictions.</p>