Abstract
This paper presents a search for direct electroweak gaugino or gluino pair production with a chargino nearly mass-degenerate with a stable neutralino. It is based on an integrated luminosity of 36.1 fb−1 of pp collisions at sqrt{s}=13 TeV collected by the ATLAS experiment at the LHC. The final state of interest is a disappearing track accompanied by at least one jet with high transverse momentum from initial-state radiation or by four jets from the gluino decay chain. The use of short track segments reconstructed from the innermost tracking layers significantly improves the sensitivity to short chargino lifetimes. The results are found to be consistent with Standard Model predictions. Exclusion limits are set at 95% confidence level on the mass of charginos and gluinos for different chargino lifetimes. For a pure wino with a lifetime of about 0.2 ns, chargino masses up to 460 GeV are excluded. For the strong production channel, gluino masses up to 1.65 TeV are excluded assuming a chargino mass of 460 GeV and lifetime of 0.2 ns.
Highlights
Supersymmetry (SUSY) [1,2,3,4,5,6] is a space-time symmetry that relates fermions and bosons
This paper presents a search for direct electroweak gaugino or gluino pair production with a chargino integrated luminosity of n3e6a.1rlfyb−m1aossf-pdpegceonlelirsaiotenswaitth√ass=tab1l3eTneeVutcroallliencot.edItbiys based on an the ATLAS
A new search for long-lived charginos yielding a pixel-tracklet signature was performed based on pp collision data collected by the ATLAS experiment at the LHC in 2015 and at
Summary
Supersymmetry (SUSY) [1,2,3,4,5,6] is a space-time symmetry that relates fermions and bosons. If a charged SUSY particle produced in a high-energy collider had a relatively long lifetime, it would leave multiple hits in the traversed tracking layers before decaying, and could be reconstructed as a track segment in the innermost part of the detector [13,14,15]. In the previous ATLAS analysis, a special tracking algorithm was used to reconstruct short tracks, and the search was sensitive to charginos decaying at radii larger than about 30 cm. A crucial improvement in the analysis described here is the use of even shorter tracks, called tracklets, which allows the reconstruction of charginos decaying at radii from about 12 cm to 30 cm.
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