I once was an active chessplayer, but work duties have long taken tournaments off my plate - I simply do not have the time to sit through long hours of chess battles. So I play blitz online on chess.com (my handle is "tommasodorigo", in case you wondered).
Just a few days ago the CDF collaboration announced their new measurement of the W boson mass, with a considerable improvement over the precision of the current world average for that quantity. Now DZERO, the competitor experiment, has also published their own new measurement, which is based on a statistics of 4.3 inverse femtobarns - twice as many data as the ones used by CDF.
As today I have just published a piece on CP violation which lacks detail on the theoretical aspects of the issue, I think it is a good time to offer you here a post on the matter written by Carl Brannen, a independent researcher and now Ph.D. student who is a great example of how what is typically dubbed "crackpottery" can at times convert into accepted science. Carl has managed to get a few of his papers accepted for publication, but he remains "on the edge", dealing with issues that many frown upon. Maybe he is right, or maybe he is not, but I sympathize with his approach, so I occasionally offer him this site for his pieces [TD].
A long awaited confirmation that direct CP violation occurs in Bs mesons (particles composed of a b- and an s-quark) not unlike what happens to lighter mesons (the K0, the B0, and the D0) is coming from LHCb. In an article appeared yesterday in the Cornell arxiv, LHCb describe their measurement of direct CP violation in the decays of both B0 and Bs mesons to Kπ final states (a kaon and a pion). The former is now the best precision measurement we have of the phenomenon, the latter is also the most precise bid (only one former measurement of the effect exists).
Today Greenpeace issued the 52-page report "Lessons from Fukushima". In it the Japanese nuclear catastrophe is analyzed in detail, and its causes and consequences exposed. The report correctly focuses on a few crucial issues: the lack of accountability for the disastrous consequences of nuclear incidents, the lack of a correct approach to the potential risks involved in the production of nuclear energy, and the failure of proper emergency planning.
Thanks to Sven Heinemeyer and his colleagues, we can give a peek today at the status of the agreement of top and W boson masses with Standard Model predictions for the Higgs boson mass, and with SUSY predictions as well. The figure below is just one of the many versions he has produced.Maybe I should not say "SUSY predictions", as it is clear, by inspecting the figure above, that the green band is quite wide, a result of the many free parameters whose value have an impact in determining the mass of the lightest Higgs scalar.
The Tevatron collider has been shut down for almost half a year now, but the CDF experiment is still busy producing world-class measurements of fundamental Standard Model parameters. Actually, the above is not quite correct: CDF is re-defining "world class" in some cases. The measurement I am going to describe, which has just been made public (if you are quick you can follow live the seminar presented by Prof. Ashutosh Kotwal at Fermilab here), totally outperforms all previous determinations of a crucial ingredient of the Standard Model: the W boson mass.
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.
