Mass Resolution Corrections at the LHC
  The utility of jet spectroscopy at the LHC is compromised by the existence of multiple interactions within a bunch crossing. The energy deposits from these interactions at the design luminosity of the LHC may degrade the dijet mass resolution unless great care is taken. Energy clusters making up the jet can be required to have an energy flow with respect to the jet axis which resembles QCD. In addition, subsidiary information such as the jet mass or the out of jet cone mass or transverse momentum can be deployed so as to alleviate the adverse effects of pileup. 
Dan Green