Search for pair-produced vector-like top and bottom partners in events with large missing transverse momentum in pp collisions with the ATLAS detector


Aad, G ORCID: 0000-0002-6665-4934, Abbott, B ORCID: 0000-0002-5888-2734, Abbott, DC ORCID: 0000-0002-7248-3203, Abeling, K ORCID: 0000-0002-1002-1652, Abidi, SH ORCID: 0000-0002-8496-9294, Aboulhorma, A ORCID: 0000-0002-9987-2292, Abramowicz, H ORCID: 0000-0001-5329-6640, Abreu, H ORCID: 0000-0002-1599-2896, Abulaiti, Y ORCID: 0000-0003-0403-3697, Abusleme Hoffman, AC ORCID: 0000-0003-0762-7204 et al (show 2906 more authors) (2023) Search for pair-produced vector-like top and bottom partners in events with large missing transverse momentum in pp collisions with the ATLAS detector. The European Physical Journal C, 83 (8). 719-.

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Abstract

<jats:title>Abstract</jats:title><jats:p>A search for pair-produced vector-like quarks using events with exactly one lepton (<jats:italic>e</jats:italic> or <jats:inline-formula><jats:alternatives><jats:tex-math>$$\mu $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>μ</mml:mi> </mml:math></jats:alternatives></jats:inline-formula>), at least four jets including at least one <jats:italic>b</jats:italic>-tagged jet, and large missing transverse momentum is presented. Data from proton–proton collisions at a centre-of-mass energy of <jats:inline-formula><jats:alternatives><jats:tex-math>$$\sqrt{s}=$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> <mml:mo>=</mml:mo> </mml:mrow> </mml:math></jats:alternatives></jats:inline-formula>13 <jats:inline-formula><jats:alternatives><jats:tex-math>$$\text {TeV}$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mtext>TeV</mml:mtext> </mml:math></jats:alternatives></jats:inline-formula>, recorded by the ATLAS detector at the LHC from 2015 to 2018 and corresponding to an integrated luminosity of 139 fb<jats:inline-formula><jats:alternatives><jats:tex-math>$$^{-1}$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mrow /> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:math></jats:alternatives></jats:inline-formula>, are analysed. Vector-like partners <jats:italic>T</jats:italic> and <jats:italic>B</jats:italic> of the top and bottom quarks are considered, as is a vector-like <jats:italic>X</jats:italic> with charge <jats:inline-formula><jats:alternatives><jats:tex-math>$$+5/3$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>5</mml:mn> <mml:mo>/</mml:mo> <mml:mn>3</mml:mn> </mml:mrow> </mml:math></jats:alternatives></jats:inline-formula>, assuming their decay into a <jats:italic>W</jats:italic>, <jats:italic>Z</jats:italic>, or Higgs boson and a third-generation quark. No significant deviations from the Standard Model expectation are observed. Upper limits on the production cross-section of <jats:italic>T</jats:italic> and <jats:italic>B</jats:italic> quark pairs as a function of their mass are derived for various decay branching ratio scenarios. The strongest lower limits on the masses are 1.59 <jats:inline-formula><jats:alternatives><jats:tex-math>$$\text {TeV}$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mtext>TeV</mml:mtext> </mml:math></jats:alternatives></jats:inline-formula> assuming mass-degenerate vector-like quarks and branching ratios corresponding to the weak-isospin doublet model, and 1.47 <jats:inline-formula><jats:alternatives><jats:tex-math>$$\text {TeV}$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mtext>TeV</mml:mtext> </mml:math></jats:alternatives></jats:inline-formula> (1.46 <jats:inline-formula><jats:alternatives><jats:tex-math>$$\text {TeV}$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mtext>TeV</mml:mtext> </mml:math></jats:alternatives></jats:inline-formula>) for exclusive <jats:inline-formula><jats:alternatives><jats:tex-math>$$T \rightarrow Zt$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>T</mml:mi> <mml:mo>→</mml:mo> <mml:mi>Z</mml:mi> <mml:mi>t</mml:mi> </mml:mrow> </mml:math></jats:alternatives></jats:inline-formula> (<jats:inline-formula><jats:alternatives><jats:tex-math>$$B/X \rightarrow Wt$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>B</mml:mi> <mml:mo>/</mml:mo> <mml:mi>X</mml:mi> <mml:mo>→</mml:mo> <mml:mi>W</mml:mi> <mml:mi>t</mml:mi> </mml:mrow> </mml:math></jats:alternatives></jats:inline-formula>) decays. In addition, lower limits on the <jats:italic>T</jats:italic> and <jats:italic>B</jats:italic> quark masses are derived for all possible branching ratios.</jats:p>

Item Type: Article
Divisions: Faculty of Science and Engineering > School of Physical Sciences
Depositing User: Symplectic Admin
Date Deposited: 29 Aug 2023 08:17
Last Modified: 18 Mar 2024 03:51
DOI: 10.1140/epjc/s10052-023-11790-7
Open Access URL: https://link.springer.com/article/10.1140/epjc/s10...
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3172366
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