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The Strange Case Of The Monotonous Running Average

These days I am putting the finishing touches on a hybrid algorithm that optimizes a system (a...

Turning 60

Strange how time goes by. And strange I would say that, since I know time does not flow, it is...

On The Illusion Of Time And The Strange Economy Of Existence

I recently listened again to Richard Feynman explaining why the flowing of time is probably an...

RIP - Hans Jensen

Today I was saddened to hear of the passing of Hans Jensen, a physicist and former colleague in...

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Tommaso DorigoRSS Feed of this column.

Tommaso Dorigo is an experimental particle physicist, who works for the INFN at the University of Padova, and collaborates with the CMS and the SWGO experiments. He is the president of the Read More »

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ATLAS has just produced a very nice new study of jet production in Z-boson events. I will describe a sample graph below, but before I do I find it useful to explain to the less knowledgeable among you what a hadronic jet is, just in case you've been away during the last forty years.

Hadronic Jets: what are they ?
One of the most intriguing effects in subatomic physics is the phenomenon of violation of the discrete symmetry called "CP". It is intriguing at various levels.

First of all, CP violation is intriguing because of the depth of the concept: proof of that be that it is not at all easy to explain it to outsiders (I will make an attempt below, but I am likely to fail!).

Second, its elusive nature makes it even more mysterious and difficult to study: only a few subatomic physical systems exhibit it, and the effect is visible only as a modification of measurable quantities at the level of a few parts in a thousand.
"It is a melancholy experience for a professional mathematician to find himself writing about mathematics. The function of a mathematician is to do something, to prove new theorems, to add to mathematics, and not to talk about what he or other mathematicians have done. Statesmen despise publicists, painters despise art-critics, and physiologists, physicists, or mathematicians have usually similar feelings: there is no scorn more profound, or on the whole more justifiable, than that of the men who make for the men who explain.
Pictures showing the structure of matter and the organization of subatomic particles in different categories abound. Indeed, cataloging and classifying entities subject of study is a powerful means of grasping their essence and infer their properties. The most striking example I can offer is the Mendeleev table of elements (which allowed its creator to spectacularly deduce the existence of elements not yet discovered); but there are many others, like the Hertzsprung-Russell diagram of star classification, or the one for galaxies, or the cataloging of animal species...
There have been other attempts in the past, so this is not strictly a new idea. However I found the interactive web page at http://htwins.net/scale2/ extremely well constructed.

It is a graphical display of the largest and smallest structures from galaxy superclusters down to quarks and the Planck length. By moving a scroll bar left or right, you can get a very clear sense of scale of the different things. And in so doing you learn the relative size of different objects, from planets to stars, or from stars to galaxies; or vice-versa, from cells to molecules and atoms.

I highly recommend it!
Now that the Higgs has been found, the current hype in popular science magazines suggests that the most pressing question in fundamental physics research is whether new particles will be found at the Large Hadron Collider: Is Supersymmetry the right extension of the standard model? Or are there new extra dimensions of space-time ? Can microscopic black holes be created in particle collisions ? I think all of you have heard some of these questions enough times by now.