I am spending my time in the CDF Control Room this week (seven days, from 4PM to midnight), as a Scientific Coordinator. My job is to work with my crew to ensure that the experiment collects good data as efficiently as possible. The data I am talking about is, of course, provided by our glorious accelerator, the Tevatron collider. Today I will tell you how the Tevatron is doing these days, and doing that will prepare the ground to my suggestion that you should become a fan of this wonderful machine.
I was notified today that within three weeks I am due to write a proceedings article for the "Physics in Collision" conference I attended in Kobe two weeks ago. The task is not too stimulating for me, given that the material it has to cover just consists in projections of the discovery reach of the Higgs boson, based on simulated data; but to add unexcitement to the whole thing, I found out that I am bound to stay within the limit of two pages of text.
In order to be able to perform unescorted access to areas where ionizing radiations are present, and to work with and use radioactive materials, workers at Fermilab have to pass a specific training which enables them to recognize the dangers and work safely, minimizing the radiation dose they get by performing their activities, and reducing the spread of contamination to the environment.
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.
What happened to all the enthusiasm? Perhaps new astronomy will shed light on the matter. In 2005 the anniversary of Einstein's miracle year there was much talk of "new Einstien"s and why there have been no new ones. Carlo Rovelli published a very good book on the subject. String theory and M theory were as hot as the surface of the sun. In a heated exchange on Wikipedia I made the acquaintance of Lubos Motl. There was much excitement 4 years ago. So what happened? Why no accepted theory of quantum gravity?
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 slide below was shown yesterday at an invited talk that Antonio Masiero gave in the University of Bologna, during an open session of the CMS Physics week (see, I am careful to note I am not breaking any rules by showing material relevant to internal CMS business: the session was open!).