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Holiday Chess Riddle

During Christmas holidays I tend to indulge in online chess playing a bit too much, wasting several...

Why Measure The Top Quark Production Cross Section?

As part of my self-celebrations for XX years of blogging activities, I am reposting here (very)...

The Buried Lottery

As part of my self-celebrations for having survived 20 years of blogging (the anniversary was a...

Twenty Years Blogging

Twenty years ago today I got access for the first time to the interface that allowed me to publish...

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Tommaso DorigoRSS Feed of this column.

Tommaso Dorigo is an experimental particle physicist, who works for the INFN at the University of Padova, and collaborates with the CMS and the SWGO experiments. He is the president of the Read More »

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I am changing my nickname on a few sites I visit - ones where a nickname is useful - to "allhadronic". The name makes reference to the hadronic final state of certain particle decays. Hadron comes from ancient greek and means "strong", and indeed the strong force is the one responsible for the binding of quarks and gluons inside protons, neutrons, and other unstable particles, collectively also called hadrons.
It has been a while since the last time I posted the last riddle of this series. It was fun though, so upon seeing the graph below I immediately decided I would use it here, to let you guess what it is about. Please use the comments thread to provide your input: what does the graph represent ? What are the different coloured lines ? Why the funny behaviour ? What is on the x axis ? And on the y axis ?



Of course it is virtually impossible to answer all the above without being given some hint. I can tell you it has to do with LHC searches, and that is all the help I am going to give you!
Ben Kilminster is a friend and a distinguished colleague working for the CMS and CDF experiments. Besides being a long-time higgs hunter, having sought that particle for over a decade in the two mentioned experiments, Ben is a veteran of science outreach since for many years he has published summaries of CDF results for the public on the online magazine "Fermilab Today". When I saw him posting on a social network an earlier version of the text below, which I liked a lot, I asked him to make it a guest post entry for my blog, and he graciously agreed.
The new PDG - a full-size copy of the glorious "Review of Particle Properties"- is on my desk since its arrival a few weeks ago, but only today did I get some time to browse it.

It is always awesome to observe how much information is contained in it. It is 1526 pages long, and I wonder how many typos and mistakes are contained in the data-thick pages... Probably much fewer than an ordinary book. Some of the review articles are of exceptionally good quality, because they have been passed from hand to hand in the last few dozen years, and constantly improved. If you want an example, for instance, go to the "Statistics" section - you will find a lot of new material which, along with the old one, still meets the highest standards.
I may have been unattentive to recent papers on Supersymmetry, but I got the impression that during the last few months the majority of SUSY phenomenologists have been keen on speculating on the few apparently non-standard features of the recently discovered Higgs boson, as published last June (such as the alleged copious decay of photon pairs, or the dearth of decays to tau lepton pairs or b-quark pairs - note: all are mostly back to what the standard model predicts, after the analysis of more data following the discovery announcements), but rather improductive on the front of taking the new signal as a pivot point for new global fits.
"Given that a repeated series of trials is required, frequentists are unable to assign probabilities to single events. Thus, with regard to whether it was raining in Manchester yesterday, there is no way of creating a large number of `yesterdays' in order to determine the probability. Frequentists would say that, even though they might not know, in actual fact it either was raining or it wasn't, and so this is not a matter for assigning a probability. And the same remains true even if we replace `Manchester' by `the Sahara Desert'.