Giddings: The 750 GeV Diphoton Resonance Is A Graviton

After the ATLAS and CMS collaboration disclosed their first Run 2 results on diphoton searches...

From The Great Wall To The Great Collider

With a long delay, last week I was finally able to have a look at the book "From the Great Wall...

Top Secret: On Confidentiality On Scientific Issues, Across The Ring And Across The Bedroom

The following text, a short excerpt from the book "Anomaly!", recounts the time when the top quark...

Choose the next topic

Being back in blogging mood, I decided I would make a poll among the most affectionate readers...

User picture.
picture for Hank Campbellpicture for Bente Lilja Byepicture for Sascha Vongehrpicture for Georg von Hippelpicture for Johannes Koelmanpicture for Josh Witten
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 »

Twenty years have passed since the first observation of the top quark, the last of the collection of six that constitutes the matter of which atomic nuclei are made. And in these twenty years particle physics has made some quite serious leaps forward; the discovery that neutrinos oscillate and have mass (albeit a tiny one), and the discovery of the Higgs boson are the two most important ones to cite. Yet the top quark remains a very interesting object to study at particle colliders.
One of the nice things about the 2012 discovery of the Higgs boson is that the particle has been found at a very special spot - that is, with a very special mass. At 125 GeV, the Higgs boson has a significant probability to decay into a multitude of different final states, making the hunt for Higgs events entertaining and diverse.
On these hot days of August one is led to remember the lyrics of Elton John's 1972 hit "Rocket Man": "and all that science I don't understand... It's just my job five days a week". Indeed, being a scientist should not be considered a mission, something you work at 24 hours a day, seven days a week. We do have our lives and attend to them... more or less.
Exotic baryons, what are they ? But first of all, what is a baryon ? Well, it depends whom you ask the question to. In the context of the static quark model, a baryon is a particle composed of a triplet of quarks, as opposed to a meson, which is a particle composed of a quark-antiquark pair. But the quark model is fifty years old, and nowadays we know better: baryons and mesons do not just contain a triplet or a duo of quarks; they are in fact a soup of quarks and gluons. What is still true is that their intrinsic properties are distinguished by the _valence_ quarks they contain.
Meteorites - stones that fall on Earth from space - are quite rare, but not so much as to make their possession impossible. In fact I know a few collectors of these strange bits of matter; and I find the very strange-looking stones quite fascinating. I myself own a small piece of tectite fallen somewhere in South Africa a few decades ago; but it is just an odd bit in a larger collection of minerals and crystals that formed on Earth (yes, I find those even more fascinating; but that's just me).
The 13 TeV data from LHC collisions taken this summer is quickly going through analysis programs and being used for new physics results, and everybody is wondering whether there are surprises in store... Of course that will require some more time to be ascertained.
For the time being, I can offer a couple of very inspiring pictures. CMS recorded a spectacular event featuring two extremely high-energy jets in the first 40 inverse picobarns of data that was collected and reconstructed by the experiment with all detector component properly working.