Searching for new phenomena with likelihood ratio tests: an overview on non-standard scenarios

by Sara Algeri (University of Minnesota)

Thursday 27 May 2021, 11:00 → 13:00 Australia/Sydney

The likelihood ratio test is a standard statistical tool widely used in astrophysics to perform tests of hypotheses. The null distribution of the likelihood ratio test statistic is often assumed to be χ2, following Wilks’ theorem.
However, in many circumstances relevant to modern experiments, this theorem is not applicable. Examples include detecting signals whose location is unknown, distinguishing new sources from known astrophysics mimicking them, and searches for new physics under background mismodeling. In this talk, I will overview practical ways to identify situations of non-regularity and  I will discuss solutions to construct valid inference in these settings.