A Quantum Diaries Survivor

This just in: the controversial Opera result on superluminal neutrinos is affected by a previously unaccounted for experimental error, which completely overturns the conclusions.This is explained in detail here. Note that the source is James Gillies, head of Communications at CERN, and thus hardly a "unofficial leak". In fact, tomorrow there will be a CERN press release on the matter.The relevant quote is the following:

About a month ago I held a three-hour course on "Statistics for Data Analysis in High-Energy Physics" in the nice setting of Engelberg, a mountain location just south of Zurich. Putting together the 130 slides of that seminar was a lot of work and not little fun; in the process I was able to collect some "simple" explanatory cases of the application of statistical methods and related issues. A couple of examples of this output is given in a post on the fractional charge of quarks and in an article on the weighted average of correlated results.

A nice new search for heavy quarks has been completed by the ATLAS collaboration in 7 TeV proton-proton collisions data collected in 2011. The ideas behind the search are instructive to describe, so I will spend some time trying to do that before I discuss the results and their meaning.Quarks: properties and decays

Of the dozens of new physics models which are currently on the market of Standard Model extensions and plug-ins, the ones hypothesizing the existence of additional dimensions of space-time beyond the 3+1 we know about are definitely among the most fascinating.

A new result by the CMS collaboration has been produced today on top quark physics. For those of you who only get triggered by the search of new particles or new forces, the study of "yesterday's signals", such as top quarks, is boring and uninformative; but high-energy physics is a rich field of research, and we extend our understanding of subnuclear physics no less by getting to know how exactly top quarks get produced in proton-proton collisions, than we do by placing limits on ephemeral particles (SUSY ones, e.g.).So I salute the new measurement as an important advance. Using over one inverse femtobarn of data collected in 2011 (about a hundred trillion proton-proton collisions), CMS was able to study top quark pairs in great detail.

You have seen it already two months ago, but those were "preliminary" results. Now both CMS and ATLAS have produced full-fledged documents (CMS here, ATLAS here) describing their respective combinations of different Higgs boson searches, using data collected in 2011 by the two experimental apparata at the CERN Large Hadron Collider.

Last week I spent a few interesting days in the pleasant winter setting of Engelberg, a mountain location in the Swiss alps. There I attended the CHIPP 2012 winter school, an event organized by Vincenzo Chiochia  from University of Zurich and Gabriella Pazstor from University of Geneva. They invited me to give a three-hour mini-course in Statistics for data analysis in High-Energy Physics, something which was a new experience for me. It took me the best part of the last couple of months to get prepared, but I was glad I did. In the end, the material I put together could have been used profitfully for five or six hours of lecture, but by skipping some of the topics I could get to the end without using a silly speed.

The CMS Collaboration has just released the results of a deep study of their sample of lead-lead collisions, produced at a center-of-mass energy of 2.76 TeV per nucleon by the Large Hadron Collider.

This week's edition of the CMS Times features a short piece by A.Rao,  where some points are made on the issue of correct statistical analysis of high-energy physics data.

...and people who like sausages, should not ask how they are made.As a member of two large scientific collaborations (CDF and CMS), I enjoy the benefit of seeing lots of scientific publications that carry my name as an author being produced at weekly rates. This is however also a burden, since I at the very least must try to ensure that I like the way the results are produced. I.e., that I agree with the details of how these scientific measurements are made.

Update: I have modified the title of this post [originally: "Opera's Statistical Booboo"] and the text below (in places I marked accordingly) upon realizing, thanks to a very good point raised by a reader in the comments thread below, that the idealization I was making of the measurement described below made my conclusions too hasty. Read the text to the end if you want more detail.

A blog is by nature a place where things move on fast. Articles disappear beyond the horizon in the matter of a week or two, and only rarely get resuscitated by a later article linking them back from oblivion. At Science 2.0 things are no better than in any other blog sites, with the aggravating feature that there is no "archive" button, nor a "random post" feature. Since I believe that many of my articles are not very connected to the specific time at which they have been written, I have in mind to reorganize the material somehow, when I have the time. However, this looks like a grievious task, since the number of posts I have written here is about 500.