Limit setting procedures and theoretical uncertainties in Higgs boson searches

Abstract

We review the CLS method used by ATLAS and CMS to set exclusion limits on the mass of the Higgs boson. We investigate the impact of theoretical uncertainties of Higgs boson cross-sections due to higher order perturbative corrections and convolution with parton densities on exclusion limits. We illustrate the impact on limits of commonly used treatments of these uncertainties with a simulated Higgs search. We adopt a "worst- case scenario" for the perturbative uncertainties. We find that the statistical methods of ATLAS and CMS do not incorporate this specific uncertainty adequately.