Today I gave a seminar at the Physics Department of the University of Helsinki, to talk of "Controversial Phenomena in Collider Data and the 5-Sigma Criterion in HEP", invited by Juska Pekkanen and Mikko Voutilanen, two CMS colleagues. 
The seminar is more or less the same I have given several times in the past year around Europe and the US. It contains some statistics, some HEP history, and some material taken from my recent book, "Anomaly!".

But this time it was special, as I had a pleasant surprise. One slide of my talk, which discusses the rationale of the five-sigma criterion for discovery-level observations, contained a 42 years old graph that I had found in a not well-known article by Roos, Hietanen, and Luoma in a journal titled "Physica Finnica". The graph shows how physics measurements underestimate their uncertainties, and it is quite instructive to discuss in a seminar like mine.

As I mentioned the name of the main author (Matts Roos), saying he had demonstrated how we should be more careful with the estimates of our systematic uncertainties, I was notified that the person I was referring to was in fact the guy sitting in front of me, whom had shown to be attentive to the talk and had already made one or two remarks during previous slides.

Speaking of Matts, he is also the author (with F. James et al.) of the cherished book "Statistical Methods in Experimental Physicists" (the first edition). 

After the talk I met him and we chatted amicably. It turns out he is not only a physicist but also an artist, and he co-authored a quite impressive large sculpture set just outside the Physics Building. The sculpture shows the distribution of galaxies around us in an artistic way. Below are Matts and I in front of his artwork:




And here is the front page of his 1975 paper, which he kindly dedicated to me in Italian:




---

Tommaso Dorigo is an experimental particle physicist, who works for the INFN at the University of Padova, and collaborates with the CMS experiment at the CERN LHC. He coordinates the European network AMVA4NewPhysics as well as research in accelerator-based physics for INFN-Padova, and is an editor of the journal Reviews in Physics. In 2016 Dorigo published the book “Anomaly! Collider physics and the quest for new phenomena at Fermilab”. You can purchase a copy of the book by clicking on the book cover in the column on the right.