Bayesian Statistics and SUSY

Abstract

Bayesian rules do not reduce the probability of something existing by as much as you would think if you eliminate a large chunk of the parameter space. Before any experiments started to have their say, I felt that SUSY at the TeV was a well motivated theory, so I might have estimated the probability of it being there as 90%. LEP had eliminated lower mass SUSY just as you might turn over a couple of cups and not find the pea. So, at the start of 2011 before the LHC started to have much to say, I estimated the probability at 75%. You might argue that another two-thirds of the parameter space has been eliminated since then reducing the probability for SUSY at the TeV scale to 50%.  For reasons discussed herein, I estimate that the probability for SUSY is now about 70%.