Dear All,
There will be an extra colloquium today at 15:00, by Brock Tweedie - you are all invited to attend:
Date & Time: Wednesday 17th April 2013, 15:00 - 16:00 Location: A1.10
Title: Cornering Light Stops at the Large Hadron Collider
Abstract: The recent discovery of the Higgs boson has firmly resolved a deep theoretical mystery, but it has brought another one into sharper focus: What stabilizes the Higgs field's potential against runaway quantum corrections? One of our best answers to this question, supersymmetry, has come under great tension as generic limits from the LHC suggest that superparticles lie well above a TeV. This tension has motivated dedicated searches for those superparticles that are most directly responsible for stabilizing the Higgs, namely stops, the supersymmetric partners of the top quark. Nonetheless, stop searches have notable blind spots even at fairly low masses, such as "compressed" spectra where the stop's decay generates very little missing energy, and "off-shell" regions of parameter space where the energy of the decay is too small to produce a physical top quark. It is therefore possible that the LHC is copiously producing these important particles, but that they remain well-hidden in the current dataset. To help make compressed and off-shell stops more visible, I will introduce a simple strategy capitalizing on the kinematic variable mT2 in the dileptonic decay channel. I will also discuss the effects of top quark spin and the lightest supersymmetric particle's identity, and touch upon other difficult decay modes that are under study.
Many thanks,
Natalie
Natalie Wells Secretariat Institute of Physics (Tues, Wed, Thurs, Fri) Secretariat Astronomical Institute 'Anton Pannnekoek' (Mon)
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