Improving SUSY Spectrum Determinations at the LHC with Wedgebox Technique

Abstract

The LHC has the potential not only to discover supersymmetry (SUSY), but also to permit fairly precise measurements of at least a portion of the sparticle spectrum. Proposed mass reconstruction methods rely upon either inverting invariant mass endpoint expressions or upon solving systems of mass-shell equations. These methodologies suffer from the weakness that one certain specific sparticle decay chain is assumed to account for all the events in the sample. Taking two examples of techniques utilizing mass-shell equations, it is found that also applying the wedgebox technique allows for the isolation of a purer event sample, thus avoiding errors, possibly catastrophic, due to mistaken assumptions about the decay chains involved and simultaneously improving accuracy. What is innovative is using endpoint measurements (via the wedgebox technique) to obtain a more homogeneous, well-understood sample set rather than just using said endpoints to constrain the values of the masses (here found by the mass-shell technique). The fusion of different established techniques in this manner represents a highly profitable option for LHC experimentalists who will soon have data to analyze.