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Title: Revealing compressed stops using high-momentum recoils

In this study, searches for supersymmetric top quarks at the LHC have been making great progress in pushing sensitivity out to higher mass, but are famously plagued by gaps in coverage around lower-mass regions where the decay phase space is closing off. Within the common stop-NLSP/neutralino-LSP simplified model, the line in the mass plane where there is just enough phase space to produce an on-shell top quark remains almost completely unconstrained. Here, we show that is possible to define searches capable of probing a large patch of this difficult region, with S/B ~ 1 and significances often well beyond 5σ. The basic strategy is to leverage the large energy gain of LHC Run 2, leading to a sizable population of stop pair events recoiling against a hard jet. The recoil not only re-establishes a ET, but also leads to a distinctive anti-correlation between the ET and the recoil jet transverse vectors when the stops decay all-hadronically. Accounting for jet combinatorics, backgrounds, and imperfections in ET measurements, we estimate that Run 2 will already start to close the gap in exclusion sensitivity with the first few 10s of fb–1. By 300 fb–1, exclusion sensitivity may extend from stop masses of 550more » GeV on the high side down to below 200 GeV on the low side, approaching the “stealth” point at m = mt and potentially overlapping with limits from tt¯ cross section and spin correlation measurements.« less
 [1] ;  [2] ;  [1] ;  [3]
  1. Rutgers Univ., Piscataway, NJ (United States)
  2. Rutgers Univ., Piscataway, NJ (United States); Stanford Univ., Stanford, CA (United States)
  3. Univ. of Pittsburgh, Pittsburgh, PA (United States)
Publication Date:
OSTI Identifier:
Grant/Contract Number:
SC0003883; FG02-95ER40896
Accepted Manuscript
Journal Name:
Journal of High Energy Physics (Online)
Additional Journal Information:
Journal Name: Journal of High Energy Physics (Online); Journal Volume: 2016; Journal Issue: 3; Journal ID: ISSN 1029-8479
Springer Berlin
Research Org:
Rutgers Univ., Piscataway, NJ (United States); Univ. of Wisconsin, WI (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS Hadronic Colliders; Supersymmetry Phenomenology