The family of Upsilon resonances is among the few things that can always cheer me up and remind me about my fascination for elementary particles when I get bored about my job. The sight of their mass peaks implies that heavy quarks bind together exactly as electrons and positrons do, orbiting around one another for a brief instant of time. An impossibly brief one, and yet quite long for subnuclear standards. It is always a refreshing and inspiring sight (below, see the three lowest-lying Upsilon states as they are seen by the CDF experiment at the Fermilab Tevatron collider, in a sizable fraction of their Run II data: lovely, aren't they ?).

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.