Topic of the Week: Low Mass Hadronic Resonances

Sunrise - WH11NE (Fermilab)

Sunrise - WH11NE


Si Xie (California Institute of Technology (US)), Zoltan Gecse (Fermi National Accelerator Lab. (US))

One explanation for the paucity of evidence for new physics at the LHC is that new physics processes decay predominantly into light quarks.  Without extra leptons, photons, or missing momentum, Standard Model multijet backgrounds dominate.  This is a daunting proposition because theoretical considerations prefer new particles that could easily be as light as 100 GeV.  The experimental challenges then are three fold: 1) recording events when the effective mass of the event is well below the current un-prescaled trigger thresholds, 2) finding discriminating variables that can reduce the multijet background by several orders of magnitude, and 3) robustly predicting the background with a minimum of theoretical guidance.  In this seminar, I will begin by considering previous searches for new physics in multijet final states, discussing the pros and cons of the methods used.  I will then examine a new technique that elegantly meets all three of the aforementioned challenges for a broad class of final state topologies. I will demonstrate the method’s sensitivity by applying it to a search for light pair-produced stop squarks that each decay into four light quarks, a topology that arises in natural R-parity-violating supersymmetry.  I conclude with a discussion of the potential of this technique for other searches in the context of natural supersymmetry.

    • 3:00 PM 4:00 PM
      Low Mass Hadronic Resonances 1h
      Speaker: John Paul Chou (Rutgers State Univ. of New Jersey (US))