The European Physical Journal C > 2017 > 77 > 12 > 1-41
Search for direct top squark pair production in final states with two leptons in $$\sqrt{s} = 13$$ s = 13 TeV pp collisions with the ATLAS detector
Source
Abstract
The results of a search for direct pair production of top squarks in events with two opposite-charge leptons (electrons or muons) are reported, using $$36.1~\hbox {fb}^{-1}$$ 36.1 fb - 1 of integrated luminosity from proton–proton collisions at $$\sqrt{s}=13$$ s = 13 TeV collected by the ATLAS detector at the Large Hadron Collider. To cover a range of mass differences between the top squark $$\tilde{t}$$ t ~ and lighter supersymmetric particles, four possible decay modes of the top squark are targeted with dedicated selections: the decay $$\tilde{t} \rightarrow b \tilde{\chi }_{1}^{\pm }$$ t ~ → b χ ~ 1 ± into a b-quark and the lightest chargino with $$\tilde{\chi }_{1}^{\pm } \rightarrow W \tilde{\chi }_{1}^{0}$$ χ ~ 1 ± → W χ ~ 1 0 , the decay $$\tilde{t} \rightarrow t \tilde{\chi }_{1}^{0}$$ t ~ → t χ ~ 1 0 into an on-shell top quark and the lightest neutralino, the three-body decay $$\tilde{t} \rightarrow b W \tilde{\chi }_{1}^{0}$$ t ~ → b W χ ~ 1 0 and the four-body decay $$\tilde{t} \rightarrow b \ell \nu \tilde{\chi }_{1}^{0}$$ t ~ → b ℓ ν χ ~ 1 0 . No significant excess of events is observed above the Standard Model background for any selection, and limits on top squarks are set as a function of the $$\tilde{t}$$ t ~ and $$\tilde{\chi }_{1}^{0}$$ χ ~ 1 0 masses. The results exclude at 95% confidence level $$\tilde{t}$$ t ~ masses up to about 720 GeV, extending the exclusion region of supersymmetric parameter space covered by previous searches.
Identifiers
journal ISSN : | 1434-6044 |
journal e-ISSN : | 1434-6052 |
DOI | 10.1140/epjc/s10052-017-5445-x |