Publication Date:
2017-11-01
Description:
A search for the supersymmetric partners of the Standard Model bottom and top quarks is presented. The search uses 36.1 fb−1 of pp collision data at $$ sqrt{s}=13 $$ s = 13 TeV collected by the ATLAS experiment at the Large Hadron Collider. Direct production of pairs of bottom and top squarks ( $$ {overline{b}}_1 $$ b ¯ 1 and $$ {overline{t}}_1 $$ t ¯ 1 ) is searched for in final states with b-tagged jets and missing transverse momentum. Distinctive selections are defined with either no charged leptons (electrons or muons) in the final state, or one charged lepton. The zero-lepton selection targets models in which the $$ {overline{b}}_1 $$ b ¯ 1 is the lightest squark and decays via $$ {overline{b}}_1o b{overline{chi}}_1^0 $$ b ¯ 1 → b χ ¯ 1 0 , where $$ {overline{chi}}_1^0 $$ χ ¯ 1 0 is the lightest neutralino. The one-lepton final state targets models where bottom or top squarks are produced and can decay into multiple channels, $$ {overline{b}}_1o b{overline{chi}}_1^0 $$ b ¯ 1 → b χ ¯ 1 0 and $$ {overline{b}}_1o t{overline{chi}}_1^{pm } $$ b ¯ 1 → t χ ¯ 1 ± , or $$ {overline{t}}_1o t{overline{chi}}_1^0 $$ t ¯ 1 → t χ ¯ 1 0 and $$ {overline{t}}_1o b{overline{chi}}_1^{pm } $$ t ¯ 1 → b χ ¯ 1 ± , where $$ {overline{chi}}_1^{pm } $$ χ ¯ 1 ± is the lightest chargino and the mass difference $$ {m}_{{overline{chi}}_1^{pm }}-{m}_{{overline{chi}}_1^0} $$ m χ ¯ 1 ± − m χ ¯ 1 0 is set to 1 GeV. No excess above the expected Standard Model background is observed. Exclusion limits at 95% confidence level on the mass of third-generation squarks are derived in various supersymmetry-inspired simplified models.
Print ISSN:
1126-6708
Electronic ISSN:
1029-8479
Topics:
Physics
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