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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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Nowadays whenever I set out to write about CMS I turn on a self-censorship co-processor in the back of my mind, one which is instructed to check that all the sentences I write are completely free from any possible misinterpretation or slant that may cause some colleagues to complain. Oh, strike that, we're a big family and we all love each other.

The topic of today is in fact potentially explosive - how experiments perform their blind searches and the potential bias that results from the detailed procedures they employ. However, you will be disappointed by reading this article if you search for scandal and flame: I am going to explain why CMS does excellent science.
Today the arxiv features the paper describing the final word by the CDF experiment on its searches for the standard model Higgs boson. This paper supersedes previous ones describing searches performed in partial datasets and including only a subset of the decay channels that have been used, so if you are interested in knowing how CDF did in the end, that is the article to read. Or the present one, if you have less time to spend on the matter, or if you are interested in an ex-post evaluation of sensitivity predictions!
The DZERO collaboration has released last week the result of their search for the rare decay of B_s mesons into muon pairs, based on the full statistics of proton-antiproton collisions acquired during Run II - a total of 10.4 inverse femtobarns of integrated luminosity.
Sabine Hossenfelder is a well-known theoretical physicist as well as a successful blogger. In her blog today I read a letter she sent to Time Magazine. The letter was triggered by the following sentence in a piece by Jeffrey Kluger discussing the runners-up for "person of the year":

“Physics is a male-dominated field, and the assumption is that a woman has to overcome hurdles and face down biases that men don’t. But that just isn’t so. Women in physics are familiar with this misconception and acknowledge it mostly with jokes.”
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!