Physics

Given the use that people do of Google searches nowadays, and the rather special nature of my usual readership, I feel I may need to first of all apologize for the deceiving title of this post to the 80 to 90% of the visitors, who came to this page by searching for ways to become a member of a selection committee of miss Universe.  Sorry, you had it wrong - we are going to discuss parametric models here, not top models. But if you are happy to hear about the issues of fitting data with different functional forms, you are welcome to read on. The problem of choosing a parametric model that…

[Update: I found the time to add a few links to the post below, which I had previously omitted for lack of time (hey I'm on vacation!), and I also updated it to add some commentary of Sabine Hossenfelder's latest post on "the end of particle physics".] In this age of short-term reward strategies (in politics, in society, and in individual behaviour) planning huge endeavours 20 years ahead is harder than it used to be. In the late eighties, when the Large Hadron Collider (LHC) was conceived and argued to be doable by a few visionaries, it immediately looked like a great idea to all.…

Supersymmetry (SUSY) is a possible extension of the Standard Model (SM), the currently accepted theory of subnuclear physics. SUSY has the potential to "explain away" some of the  problematic features of the SM, by introducing a new symmetry between fermions (the stuff that matter is made of) and bosons (the vectors of the forces that hold matter together). Introduced in the seventies, SUSY was tested with increasingly stringent tests in higher- and higher-energy collisions at particle accelerators, but all searches for its particles have returned empty-handed. In particular, many…

I don't remember who said it, but there's a quote I like a lot: "If you torture them long enough, the data will confess to anything". What the author meant is of course that the manipulation of experimental data and the a posteriori use of hand-picked methods, approximations, and other ad-hoc choices allows you to demonstrate anything with them, from one hypothesis to the opposite one. Statistics, in other words, is a subtle science, which must be handled with care. It is a powerful tool in the hands of people with an agenda.  Yet I do not wish to discuss here how to lie with Statistics…

My CMS colleague Didar Dobur, who chairs the "Top Properties" working group in the experiment, presented today the first observation of the process whereby a top quark is produced in association to a Z boson. I could follow the presentation by videoconference, so I am blogging about this result in close to real time, for a change.These "tZq" events are peculiar for several reasons: first of all, they involve two of the heaviest elementary particles we know. The top quark is the heaviest, with a mass of 173 GeV - or about 185 proton masses; and the Z boson weighs 91 GeV, or about 97 proton…

What machine will replace the Large Hadron Collider to further our knowledge of fundamental physics at the high-energy frontier, in the forthcoming decades?  The question is not at all a far-fetched one: these large machines require two decades to be built - and can then typically be operated for two further decades, amassing collision data that slowly but steadily improve the precision of our estimates of the parameters of nature.Of course, there are those who hold that the absence of any hints of new physics in LHC data should lead us to put our future programs to a pause. The argument…

22 transgender people on the list of those killed by violence.  Most of whom are transgender women of color.  Transgender visibility week is underway and last from November 13 to 19th every year.  The day of remembrance, November 20th, has been observed by the trans community since 1998.UPDATE:Crunchyroll.com a localize of anime into US English choose to accurately translate a character as transgender rather than applying the word trap to them as done in the past. A number of us made them aware of the issue and the effect of that word and they listened. Sadly they also caught…

As I mentioned in yesterday's post, there is a workshop going on this week at Fermilab, where 110 attendees - mostly particle physicists, but some computer scientists are also present - discuss how to push for more effective use of machine learning tools in the extraction of information on particle collisions.  Also one goal is to understand what new ideas from the world of machine learning could find ideal applications in the typical use cases of research in fundamental physics. Here I wish to mention a few interesting things that I heard at the workshop so far, in random order. I will…

I flew to the US yesterday to get to Fermilab, where I am following a workshop titled Machine learning for jet physics". My goal of this post is to explain what this is about in general terms, such that if I have enough stamina I will give, in follow-ups to it, a few examples of the status of this interesting research activity, which encompasses particle physics and computer science and can provide spin-offs in a number of related areas of fundamental research.First of all, machine learning. This is a booming field of research, which employs computer programs capable of learning from examples…