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.