Last Tuesday I presented new precise Tevatron results on top quark physics at the "LHC Days" conference in Split. The top-quark measurements that CDF and DZERO have produced with their multi-inverse-femtobarn datasets of proton-antiproton collisions are very precise, and they surpass pre-Run-II expectations: suffices to say that the top-quark mass is now estimated with a 0.61% uncertainty, over twice smaller than promised. So it was nice to display these results to an audience mainly composed of LHC colleagues. I received several questions and the interest in my talk was clear.

I am spending a few pleasant days in Split for the conference "LHC Days". I will be representing the D0 and CDF collaborations here in a talk on top physics at the Tevatron; in the meantime, I am pleased to witness that talks are of high quality. This morning the most interesting to listen to (at least to me) was the one by Guido Altarelli, a distinguished theorist from the University of Roma III. Altarelli has given crucial contributions to the advancement of our understanding of Quantum Chromo-Dynamics in the seventies, and it is always a pleasure to listen to him (a previous report of a talk he gave in Perugia two years ago is here).

I will be attending next week to a conference in Split (Croatia). The conference is titled "LHC Days", and has the purpose of bringing together experimental physicists working at the main CERN experiments with theorists and experimentalists from all over the world, to discuss the current status and the future perspectives of research in particle physics, focusing of course on the Large Hadron Collider at CERN.

Georges Charpak, a French physicist and 1992 Nobel Prize winner, died yesterday.

Of Polish origin, Charpak gave crucial contributions to experimental physics, in particular for his invention of the multiwire proportional chamber in 1968.

Back then, the signal of passage of charged particles was recorded by bubble chamber images and images triggered by spark chambers - where the charge deposition would create a discharge in a very high electric field.

The Large Hadron Collider is increasing gradually the number of proton bunches that circulate in the machine. Yesterday's fill saw 104 colliding proton bunches,  producing the record instantaneous luminosity of 3.5 x 10^31 collisions per square centimeter per second. This is no surprise, of course: luminosity is essentially the product of the number of particles crossing each other per second divided by the cross section of the beams, so if you increase the particles and manage to keep the beam transverse size constant, luminosity must go up.