A Quantum Diaries Survivor

There were several interesting talks today at the CDF Collaboration meeting. Rather than going into details, however, I will just show a nice slide by Jacobo Konigsberg, our new Spokesperson. Jaco gave an overview of the status of the experiment, what we achieved so far, and the challenges we are facing. 

Here is the slide which impressed me. It is very descriptive, and although it contains a lot of information, it is certainly possible to explain it to non-insiders.

In the plot, the y axis represents a number proportional to the probability that a proton-antiproton collision in the CDF detector will produce a given particle or process. The various colored steps are the things you can produce.

A pair of jets (in red) is the most common thing coming out of the collision. You get that once every 50 collisions or so. Harder is to produce a bottom quark (in blue): that happens ten times less frequently. But to produce a W or a Z boson, you have to be yet 10,000 times luckier. And if you want to get a top quark, you'll have to wait a thousand times longer still: once every 5 billion collisions.

At that point, the rest is still to be discovered: it is a fishing expedition where the deeper you go fishing, the more interesting things you might find. Higgs bosons might be just a hundred times less frequent. But at that same level of frequency, we might be producing signals of leptoquarks, extra dimensions, supersymmetric particles. A whole new world of particle physics might open up if we fish deep enough.

So how do you go fishing deeper ? You produce more collisions, of course. But not just that: the more background events you collect per each signal event you need, the harder it will be to recognize that small signal, and the smarter you'll need to be. So it is not just a matter of collecting more data, but also of improving your discrimination tools and your selection algorithms.

I talked a bit about signal-to-noise discrimination in the former post today, so I will stop here now.