Tomorrow I will be packing up and leaving CERN to fly back home, after a quite eventful, productive, extenuating, exhilarating week. The reason for my coming to Geneva was the CMS week, an event that takes place four times a year, and where a good fraction of the members of our 2400-strong collaboration gather to listen to updates of the experiment, the detector, the analyses, and to discuss rules, appointments, organizational issues.

One of the cool things I have learned to do, through years of experience in data analysis at particle colliders, is to visualize the complex kinematics of a signal process in a multi-dimensional space, and imagine ways to separate it from backgrounds by selecting in the hyperspace the signal-rich region. I came across a very simple example of the above rather abstract statement yesterday, and I wish to share it with you.

To help you visualize what I am going to discuss, here is the example: an avocado in a square tumbler. The avocado is top pair production, and the glass is Z plus b-antib production.

... Confused ? Let me explain.

I do not know about you, but top quarks fascinate me. Since my early years as a student in particle physics I participated in the top search, and then the top discovery, with the CDF experiment at the Tevatron collider; and I then worked for many more years with top quark samples. And that particle is fascinating for many different reasons: its phenomenology, the richness of its decays, its mass close to the scale of electroweak symmetry breaking.

I feel honored by having had a chance to study the first few tens of top quark events that physicists have been able to produce, and yet I regret that during the last few years I have been unable to put my hands on the much larger datasets collected by the CDF experiment.