Meteoroid Caught Free-Falling On Video ?

A meteor caught on film during its non-luminous free fall at terminal velocity ? Or an elaborate...

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Long-time readers of this blog (are there any left ?) know me well since I often used to ...

Aldo Menzione And The Design Of The Silicon Vertex Detector

Below is a clip from a chapter of my book where I describe the story of the silicon microvertex...

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Yesterday I was in Rome, at a workshop organized by the Italian National Institute for Nuclear...

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Tommaso DorigoRSS Feed of this column.

I am an experimental particle physicist working with the CMS experiment at CERN. In my spare time I play chess, abuse the piano, and aim my dobson telescope at faint galaxies.... Read More »

The turnaround of the three physics questions I offered a few days ago, to stimulate your neurons and extract you from the chocolate and alcohol flood caused by the usual string of Christmas parties and dinners, was rather scarce. Despite that, I wish to repeat the offer today, making some adjustments to reach a wider public. The questions I offer here are easier but still not accessible to everybody. However, my plans are that at least the answers I will give in a couple of days will be understandable. Further, anyone can try the bonus question I ask at the bottom of this piece...
Two days ago I offered you three problems in experimental particle physics, of varied complexity. Three readers tried answering the test in the comments thread: a rather underwhelming turnaround, but what did I expect - we are deep in Christmas vacations after all.

I will give below my own answers to the questions, and then comment some of those I received. For ease of reading, I paste here again the three questions.
Scared by the void of Christmas vacations ? Unable to put just a few more feet between your mouth and the candy tray ? Suffocating in the trivialities of the chit-chat with relatives ? I have a solution for you. How about trying to solve a few simple high-energy physics quizzes ?

I offer three questions below, and you are welcome to think any or all of them over today and tomorrow. In two days I will give my answer, explain the underlying physics a bit, and comment your own answers, if you have been capable of typing them despite your skyrocketing glycemic index.
This blog wishes you a very Merry Christmas, if...

You would not really expect me to wish Merry Christmas à tout le monde, right ? I hate nobody, but the fact you visit my site on December 24th does not make you eligible to have my sympathy, by itself. There are a few -very few- things that I attach as a condition for my best wishes.

So, Merry Christmas to you, and your loved ones,

  • if you live in the knowledge that you are a guest on this planet, and make an effort to keep it good for those who will one day take your place in it;
  • if you hate nobody, and reject violence and war as means of resolution of controversies;
It is over, but it was frantic. Luca, the Ph.D. student who works with me at the analysis of CMS data (the one which has brought us to the approval of a first signal of the phi meson) summarized it best on Tuesday evening, at the party thrown by our big boss Dario. Holding a glass of good wine in his right hand, and a platter of assorted appetizers in the other, he said: "It is a delirium to work with you: your activity profile is a succession of Dirac deltas".
Just a short note, a record to be precise. Last night the sea water level rose to +1.35 meters above average in the Venice lagoon, in a quite uncharacteristic quarter-moon surge triggered by low pressure conditions on the Adriatic sea. Tonight and tomorrow night two more surges of the same entity are predicted, as shown in the following graph.

The blue line shows the predicted tide, while the red line shows the astronomical tide (the one which would occur under average atmospheric conditions). The surplus of almost one meter of water is due to exceptional conditions.