Reference priors for high energy physics Luc Demortier Laboratory of Experimental High Energy Physics, Rockefeller University, New York, New York 10065 Supriya Jain Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, Oklahoma 73019 ∗ Harrison B. Prosper Department of Physics, Florida State University, Tallahassee, Florida 32306 (Dated: October 24, 2018) Bayesian inferences in high energy physics often use uniform prior distributions for parameters about which little or no information is available before data are collected. The resulting poste- rior distributions are therefore sensitive to the choice of parametrization for the problem and may even be improper if this choice is not carefully considered. Here we describe an extensively tested methodology, known as reference analysis, which allows one to construct parametrization-invariant priors that embody the notion of minimal informativeness in a mathematically well-defined sense. We apply this methodology to general cross section measurements and show that it yields sen- sible results. A recent measurement of the single top quark cross section illustrates the relevant techniques in a realistic situation. PACS numbers: 06.20.Dk,14.65.Ha ∗ Now at the State University of New York, Buffalo, New York 14260 1 arXiv:1002.1111v2 [stat.AP] 6 Jul 2010 Abstract