Constricted SUSY from No-Scale ℱ-SU(5): A “blind spot” for LHC top quark reconstruction?

¹ State Key Laboratory of Theoretical Physics and Kavli Institute for Theoretical Physics China (KITPC), Institute of Theoretical Physics, Chinese Academy of Sciences - Beijing 100190, PRC
² George P. and Cynthia W. Mitchell Institute for Fundamental Physics and Astronomy, Texas A&M University College Station, TX 77843, USA
³ Department of Physics and Astronomy, Ball State University - Muncie, IN 47306 USA
⁴ Astroparticle Physics Group, Houston Advanced Research Center (HARC), Mitchell Campus Woodlands, TX 77381, USA
⁵ Academy of Athens, Division of Natural Sciences - 28 Panepistimiou Avenue, Athens 10679, Greece
⁶ Department of Physics, Sam Houston State University - Huntsville, TX 77341, USA

Received: 20 July 2013
Accepted: 29 October 2013

Abstract

We describe a region of the No-Scale supersymmetric model with TeV-scale vector-like matter multiplets that is potentially opaque to LHC observations based upon top quark reconstruction. Possessing a 100% on-shell branching fraction for gluino-to-light stop decays, the gluino-light stop mass splitting in lies very close to the top quark rest mass in the region . For unboosted gluino pair production, this could render two soft top quarks in the dominant 4-top signature, greatly reducing the likelihood for discrimination from the combinatoric background. We therefore suggest that caution is warranted when gluino exclusion bounds on models possessing a similar spectral character (gluino heavier than the light stop but lighter than all other squarks) using multijet SUSY search tactics. Alternate search methods are highlighted, including those based upon same-sign dileptons and multiple heavy flavor tags, which are more sensitive to this delicate kinematic “blind spot” crease.