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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...

2026 Plans

This year opened in slow motion for me, at least work-wise. I have been on parental leave since...

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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 and the SWGO experiments. He is the president of the Read More »

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"There is, in my opinion, no doubt that by the time we are ready to announce the discovery of the Higgs boson, the whole world will know it".

James Gillies, Head of Communications at CERN, interviewed by Physics World's Matin Durrani - video available here.
Fermilab is a wonderful place to travel to in the late summer or fall. The site of the laboratory is a wide chunk of land just east of the Fox river, 30 miles west of Chicago. It is home to not just physicists and engineers, but to a wide variety of animals. Geese on their way South stop yearly in the lake in front of Fermilab's Wilson Hall, and many of them decide to spend the winter there, to benefit from the warm waters; deer are copious, but will not be easily seen around, save for the occasional one at times seen standing in the middle of the road at night; buffalos roam within large lots of land outside and inside the ring. Woods, trees with widely varied colours, and prairie make one feel it is a privilege to do Science there.
Today I wish to bring to your attention a figure recently obtained by the CDF collaboration, one which really tells a thousand words. Before I describe it to you, however, I would like to discuss at an elementary level a few basic concepts of particle theory which the figure well summarizes.


A Crash Course on Feynman Graphs


Let us start with a few elements on Feynman graphs -the diagrams that physicists use to draw on their blackboards to picture what really happens when particles react, and that actually enable the computation of the probability of those processes.
"The emission or absorption of a quantum by a nucleus bound in a crystal leads in general to an alteration of the vibrational state of the crystal lattice, which takes up the recoil momentum. On account of the quantization of the internal energy, the crystal can absorb the recoil energy only in discrete amounts. With decreasing temperature the probability of excitation of the internal states decreases more and more, so that for soft gamma rays for a part in the quantum transitions the crystal as a whole takes up the recoil momentum. The quanta emitted or absorbed in this situation undergo practically no energy loss because of the large mass of the crystal, and ideally satisfy the resonance condition".

Rudolf Mossbauer
New beautiful images from the Hubble Space Telescope (HST) have been released recently, and they are, as always, a pleasure to behold. The HST was serviced in a mission by the Space Shuttle Atlantis crew last May, to replace some broken gyroscopes and drained batteries, and perform a number of additional important tasks that will allow operation to continue for many years to come.

Among the new installed instruments the new HST sports an improved wide field camera, WFC3, which promises a significant improvement of the quality of telescope's imaging capabilities.
Data concerning the parties with 30 young beauties (paid 1450$ each for their time, plus various benefits and gifts) held by the Italian Premier Silvio Berlusconi in his residences in Rome and Sardinia, between September 2008 and January 2009, have been disclosed the other day by the provider of the girls, Giancarlo Tarantini. Tarantini is under investigation for several charges (including, it seems, drug abuse and distribution at his own parties), and he is spilling his guts.  We thus learn from him that many of the involved girls allegedly spent the nights at the Premier's house providing sexual favors to their host; the fact appears to be confirmed in at least one case with video and audio recordings taken by escort Patrizia D'Addario.