Speaker
Prof.
Lance Dixon
(SLAC National Accelerator Laboratory (US))
Description
The prediction of backgrounds to new physics signals in topologies
with large missing transverse energy and jets is important to new physics searches at the LHC. The BlackHat collaboration has investigated theoretical issues in extrapolating backgrounds from experimental control regions to signal regions. For example, we compute, ratios of gamma + n-jet to Z + n-jet production rates and kinematic distributions in NLO QCD, and compare with a parton shower matched to leading-order
matrix elements. These predictions validate uncertainty estimates used by CMS for the irreducible Z + n-jet component of MET+jets searches. We also describe the phenomenon of left-handed W polarization at large
transverse momentum, its theoretical prediction and recent measurement by CMS and ATLAS, and its potential role in background separation.
Author
Prof.
Lance Dixon
(SLAC National Accelerator Laboratory (US))
