The Strange Case Of The Monotonous Running Average

These days I am putting the finishing touches on a hybrid algorithm that optimizes a system (a...

Turning 60

Strange how time goes by. And strange I would say that, since I know time does not flow, it is...

On The Illusion Of Time And The Strange Economy Of Existence

I recently listened again to Richard Feynman explaining why the flowing of time is probably an...

RIP - Hans Jensen

Today I was saddened to hear of the passing of Hans Jensen, a physicist and former colleague in...

Tommaso Dorigo

Tommaso Dorigo is an experimental particle physicist, who works for the INFN at the University of Padova, and collaborates with the CMS and the SWGO experiments. He is the president of the Read More »

Italian Elections: Berlusconi, Grillo, And The Stalemate Scenario

Feb 19 2013 | comment(s)

Next Sunday Italians will vote to change the composition of the two houses of parliament: the "lower" Camera dei Deputati and "upper" Senato della Repubblica. And as often happens with Italian politics, things are complicated. So, despite this site is mostly visited for other reasons than trivialities about politics in foreign countries, I thought I would provide here my own short-sighted, biased panorama of the situation.

Neutrino Telescopes XV

Feb 14 2013 | comment(s)

Every two years physicists and astrophysicists who work in the area of neutrino physics get together in the wonderful setting of Palazzo Franchetti, a historical palace on the Canal Grande in Venice, Italy, to discuss the latest results of experiments and theoretical ideas, and to plan for the future.

The Quote of the Week - Peter Higgs: Inventing an Elementary Particle

Feb 13 2013 | comment(s)

I quickly wrote a short paper, "Broken Symmetries, Massless Particles and Gauge Fields", which described how gauge theories may evade the Goldstone theorem, and submitted it to Physics Letters. It was received on 27 July and published 15 September. Before writing up the work on what is now known the Higgs model I spent a few days searching the literature to see whether it had been done before. I thought that Schwinger, in particular, might well have done something of the kind years earlier and I might have overlooked it. When I had satisfied myself that he hadn't, I wrote a second short paper, "Broken Symmetries and the Masses of Gauge Bosons", and submitted it too to Physics Letters. It was rejected.

The Mysterious Y(4140)

Feb 11 2013 | comment(s)

Quite some time ago I discussed here the tentative Y(4140) resonance claimed by the CDF collaboration in their Run II data. This was a peak which was found in B-decay data containing a J/Psi signal, a phi meson, and an additional kaon track, and it resulted from the study of the mass difference of the J/Psi + phi signal and the J/Psi alone.

Confused ? You have all rights to be. I will explain everything in good order, but be sure that the matter was puzzling not only for laymen but also for insiders: because the find was mysterious, not predicted by existing models, and potentially controversial.

B Decays and the CDF Claim

What's The Omega_b Mass? LHCb Confirms CDF, DZERO Way Off

Feb 07 2013 | comment(s)

The Omega_b particle is a quite peculiar baryon, made up by three heavy quarks: a b-quark, and two s-quarks. Because of this composition, where only down-type quarks appear, the phenomenology of the decay of this particle is really spectacular: both the b-quark and the strange quarks take quite some time to decay, and as they take shifts to do it the Omega_b first transmutes into a Omega (a particle made up by three s-quarks!), then into a Lambda, and finally into a proton.

Each of these decays generates a reconstructable decay point, so one can reconstruct the whole chain perfectly. A sketch will clarify matters - see below.

On The CMS Higgs Video, Bias And Variance

Jan 31 2013 | comment(s)

Nowadays whenever I set out to write about CMS I turn on a self-censorship co-processor in the back of my mind, one which is instructed to check that all the sentences I write are completely free from any possible misinterpretation or slant that may cause some colleagues to complain. Oh, strike that, we're a big family and we all love each other.

The topic of today is in fact potentially explosive - how experiments perform their blind searches and the potential bias that results from the detailed procedures they employ. However, you will be disappointed by reading this article if you search for scandal and flame: I am going to explain why CMS does excellent science.