CMS Looking Back

Abstract

The collaborations like to make big statements about how they do their analysis blind. This is supposed to mean that they don’t look at the results until they have fixed the parameters of the analysis so that they cannot introduce any bias. From a CMS video, we can see what this really means in practice. They unblind the data as an early check then they “re-blind” it while they adjust the analysis. They unblind it again two weeks later with just 30% more data added. This is not quite in the spirit of how blind analysis is meant to work. Luckily the signal is so clear that it is indisputable in any case.