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Anomaly! Now Available As E-Book

Today I would like to mention that my book "Anomaly! Collider Physics and the Quest for New Phenomena...

Two Physics Blogs You Should Not Miss

I would like to use this space to advertise a couple of blogs you might be interesting to know...

The Six-Month Cycle Of The Experimental Physicist

Every year, at about this time, the level of activity of physicists working in experimental collaborations...

LHCb Finds Suppressed Lambda_B Decay

The so-called Lambda_b baryon is a well-studied particle nowadays, with several experiments having...

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Tommaso DorigoRSS Feed of this column.

Tommaso Dorigo is an experimental particle physicist, who works for the INFN at the University of Padova, and collaborates with the CMS experiment at the CERN LHC. He coordinates the European network... Read More »

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While the LHC runs like a swiss train and collects dozens of inverse picobarns a day, there's a celebration going on on the other side of the Atlantic, as this picture testifies:



The folks pictured here at the Fermilab village have a reason to cheer up: the glorious Tevatron has just delivered 11 inverse femtobarns of proton-antiproton collisions to CDF and DZERO. What a huge achievement that has been!
Upon being reminded by an automated messaging system, somewhat disturbingly, that today would be the birthday of an esteemed colleague -were he not dead- I decided to post a "guess the plot" entry which pays him a tribute.

The figure below is for you to guess (ignore the blue box at the lower right -it just hides some giveaway information). What does it represent ? What is in the abscissa ? And on the y axis ? Why do the data only populate the upper left half ? And what causes those two funny concentrations ?
Please try your luck and make your guess in the comments thread! It's fun, it's free, it makes me happy to see you considered the riddle, and it adds interest to this column!
A few months ago LHC took a special run of proton-proton collisions at  2.76 TeV. Why the lower energy, now that we are accustomed to searching for new phenomena at the highest available energy of 7 TeV ? Because of the wish to compare lead-lead collisions, taken last year at 2.76 TeV nucleon-nucleon energy, with proton-proton ones. The comparison allows to extract extremely interesting results.
Just a short post to mention that the Large Hadron Collider has reached tonight the top instantaneous luminosity of 1.075 * 10^33 cm^-2 s^-1. This is a new record for high-energy hadron colliders, improving over precedent records already set this year by the CERN machine. The peak luminosity is 2.5 times larger than the highest reached at the Tevatron (which, one needs to remember, collides protons against antiprotons, and the difficulty in producing the latter makes the comparison between LHC and Tevatron luminosity a bit deceiving).
The plot of the week is actually a table this week. A histogram with several background components can be extremely informative, but sometimes a table provides more detail and one can focus better on interesting features.

The table below has been produced in a CDF search for events containing same-sign lepton pairs: a striking signature of new physics, faked by very few processes. Because of the paucity of Standard Model sources, even relatively small new physics signals can emerge in such a sample. The CDF analysis is based on 6.1 inverse femtobarns of proton-antiproton collisions collected at the Tevatron during Run II. Let us see what the table tells us.


Last night I had the pleasure to visit Mauro, a friend of mine and an amateur astronomer. Mauro owns a 24" dobson telescope with a mirror crafted by the superb hands of Romano Zen, the same who made my own 16". The precision of the optics of Romano is legendary, and as far as my limited capabilities allow me to judge, his reputation is entirely deserved. With my dobson scope I have been able, in nights of lucky seeing, to discern details on Jupiter of the order of half an arcsecond in angular extension. And with Mauro's 24"...