Significance calculation and a new analysis method in searching for new physics at the LHC

Abstract

The LHC experiments have great potential in discovering many possible new particles up to the TeV scale. The significance calculation of an observation of a physics signal with known location and shape is no longer valid when either the location or the shape of the signal is unknown. We find the current LHC significance calculation of new physics is over-estimated and strongly depends on the specifics of the method and the situation it applies to. We describe general procedures for significance calculation and comparing different search schemes. A new method uses maximum likelihood fits with floating parameters and scans the parameter space for the best fit to the entire sample. We find that the new method is significantly more sensitive than current method and is insensitive to the exact location of the new physics signal we search.