Special Article - Tools for Experiment and Theory

The European Physical Journal C

, 71:1554

Open Access This content is freely available online to anyone, anywhere at any time.

Asymptotic formulae for likelihood-based tests of new physics

  • Glen CowanAffiliated withPhysics Department, Royal Holloway, University of London
  • , Kyle CranmerAffiliated withPhysics Department, New York University
  • , Eilam GrossAffiliated withWeizmann Institute of Science
  • , Ofer VitellsAffiliated withWeizmann Institute of Science Email author 


We describe likelihood-based statistical tests for use in high energy physics for the discovery of new phenomena and for construction of confidence intervals on model parameters. We focus on the properties of the test procedures that allow one to account for systematic uncertainties. Explicit formulae for the asymptotic distributions of test statistics are derived using results of Wilks and Wald. We motivate and justify the use of a representative data set, called the “Asimov data set”, which provides a simple method to obtain the median experimental sensitivity of a search or measurement as well as fluctuations about this expectation.