A Quantum Diaries Survivor

This week's graph comes from a recent publication by the CMS experiment, the one I am a proud member of together with about 3000 colleagues from all over the world.

To the couple of positions I posted yesterday from the Chess Tournament I played this weekend, let me add one I played on round II, when I was white against Fausto Scali, the blind player. The position arose from the Advance variation of the French defense (1.e4 e6 2.d4 d5 3.e5), which however we reached with a transposed move-order (1.e4 c5 2.c3 d5 3.e5). In the position below, black has just played an inaccuracy in an already slightly worse queenless middlegame:

Chess is a game, a sport, and a very radical way to test one's concentration and discipline in pure thought. Besides liking it as a game (a precondition to enjoy the other benefits), I also enjoy immensely the demands that a chess game puts on your brain's functioning; and this is brought to the extreme during a chess tournament, where you are also subject to pressure from competition factors extraneous to the 64 squares where the battles develop.

No, unfortunately not yet the discovery of the century. Still, the new particle found by CMS in its 2011 dataset is a very important piece of the puzzle of low-energy spectroscopy. Here "low" should be taken with a pinch of salt: the new particle, an excited state of the Ξ_b series, has a mass only slightly lower than six GeV, and is thus "heavy" if compared to most other hadrons.

When I started a career in particle physics, joining the CDF experiment at the Fermilab Tevatron proton-antiproton collider about two decades ago, the search for a particle decay signal into hadronic jets was not something one would undertake lightly at a hadron collider: jets are omnipresent when you collide hadrons at high energy, so they constitute a irreducible background. Just as a detective looking for a blonde thief with swedish accent in Sweden, you would be close to clueless.

A couple of weeks ago the CDF and DZERO experiments have produced a combination of their measurements of the W boson mass. Besides two older determinations of this fundamental parameter of the Standard Model, the new 2.2/fb measurement by CDF and the 4.3/fb measurement by DZERO have been averaged together, accounting for correlated systematics. [x/fb is a shorthand for the amount of collisions from which the W boson datasets have been extracted by the experiments: 1/fb is about 80 trillion proton-antiproton collisions.]

I am just back from a vacation to Greece, where last Sunday was orthodox Easter. My fiancee Kalliopi is Greek, and it was about time for me for me to experience a bit of Greek customs. So we flew to Athens, and then headed to Salamina, where I had a lot of fun the Greek way in the company of a very cheerful dozen of relatives and friends.Among the obligatory ingredients of a Greek Easter is the roasted lamb. It is cooked all in one piece, on a huge skewer, by rolling it for hours over hot coals. Its appearance is a bit disturbing at first, that is until the smell start to turn from that of a corpse to that of delicious food.  Below you can see me in front of the thing as it was already in the good-smelling and edible-looking phase.

For once I allow myself some self-advertising... I just published on the Cornell arXiv the preprint of a proceedings paper I wrote for the Bormio 2012 conference on Nuclear Physics, where I presented the most recent results from the CMS experiment in a review talk. The paper is titled "Recent Results of the CMS Experiment".The paper is 33-pages long, and thus configures as a general review of the results that CMS produced from the analysis of data collected during 2011, the 5 inverse femtobarns of proton-proton collisions, which among other things granted a first feeble but trustworthy evidence of a Higgs boson when read together with similar ATLAS results.

A powerful earthquake has struck an hour ago, at 8.30UT, very close to the place where a similar event occurred on December 26th 2004. The earthquake has an estimated magnitude of 8.7 and occurred at a depth of 33km, according to NOAA. The map below shows the location of the event and the potentially affected areas.

Last week the Large Hadron Collider has started producing collisions at the record high 8-TeV centre-of-mass energy to the ATLAS and CMS detectors. In the course of the first week of run almost 200 inverse picobarns have been delivered to CMS, which is absolutely satisfactory. The integrated luminosity versus time is shown below.And here is the peak instantaneous luminosity reached during these first few days of running:(NB: I believe the above figure lacks a "s^-1" units).

And after all I said about Supersymmetry being an invention, I fear I now have to eat it all with my hat to boot ! The ATLAS Collaboration has just released results of a very striking search for gluinos, which increases the sensitivity over past analyses by employing a much improved and cleaned-up version of missing transverse energy along with a higher-resolution version of the effective mass variable used in the past, and has found a first strong evidence for Supersymmetric decays !!

Antonio Ereditato (left), spokesperson of the Opera collaboration, announced today he stepped down. He is no longer leading the Opera experiment. The Opera experiment last September made headlines around the world with their announcement that neutrinos sent from the CERN laboratories to the Gran Sasso cavern appeared to be moving at superluminal speed.