Brookhaven Forum Live Blog IV

First Parallel session.  Conference website

Abhishek Kumar, Searching for Very Light Stops

• Stops relevant for naturalness, take the case m_stop < m_top.
• Non-standard stop decays: b-W-neutralino with W on/off shell, c-neutralino.
• Use MFV to handle the flavour-violating decays.
• Flavour-violating decay can dominate over four-body decay, even when both are allowed.  Depends on left/right handed nature of lightest stop.
• ISR needed to account for MET properly.
• Limits up to ~250 GeV.

Sujeet Akula, Gluino-driven Radiative Breaking in Grand Unified Supergravity

• Pointed towards Higgs to two photons, among other things, as evidence for light sleptons
• Of course, also lots of things that push SUSY scale up.
• Good talk, but too long on the background.  Get to what's new before you run out of time!
• Basic structure: gluino mass at GUT scale is much larger than the other soft masses.
• Heavy gluino drives squarks heavy and radiatively breaks EWSB.
• Higgsino mass mu also driven large.
• Large seems to mean a factor of 10.
• Non-universal gaugino masses need non-trivial GUT-scale Higgses.

This is claiming a lot for only tweaking the CMSSM by one number.

Eva Popenda, Squark Pair Production at NLO matched with Parton Showers

• NLO standard is Prospino, which assumes that all squarks degenerate.
• Go beyond that for the first time in an event generator.
• This is all a bit technical for me.
• Even when squarks degenerate, subchannel cross sections disagree: Prospino assumption (all subchannels identical) not exact.
• NLO corrections can give ~20% corrections to shapes of distributions.