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Life After The 125 GeV Higgs: What Is Left Of Two-Higgs Doublet Models

I just read with interest the new paper on the arxiv by my INFN-Padova colleague Massimo Passera...

The Quote Of The Week - Richter On The Landscape

"If you have seen the movie Particle Fever about the discovery of the Higgs boson, you have heard...

The Graph Of The Week: No Dark Photons Found By ATLAS Lepton Jets Search

Among the viable extensions of the standard model, an intriguing class of models involve the concept...

How The Higgs Became The Target Of Run 2 At The Tevatron

Until the second half of the nineties, when the LEP collider started to be upgraded to investigate...

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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 »

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You are the first to arrive to a dinner party and must choose the table where to sit, relying on your past experience of how handsome members of the opposite sex (you're straight) usually choose their seat. You need to buy stocks based on past performances and trends. You travel to some distant location and would like to know what's the weather like there, but there is no forecast for that particular place. What do you do ?
Programmers may not be the guys with the best sense of humor around, but I found it quite entertaining to read a web page with a collection of source code comments arising a smile.

The one I liked the most is the following - not even a comment, but the way the guy called the object he instantiates:

"After the 1974 London Conference, with its strong confirmation of the quark model, a general change of view developed with regard to the structure of hadrons. [...] the quark structure of hadrons became the dominant view for developing theory and planning experiments. A crucial element of this change was the general acceptance of QCD, which eliminated the last paradox, namely, why are there no free quarks ? The conjectured infrared slavery mechanism of QCD provided a reason to accept quarks as physical constituents without demanding the existence of free quarks. The asymptotic freedom property of QCD also provided a ready explanation of scaling [...].
One of the nice details lost in the big picture of the Higgs boson discovery of 2012 is that a significant part of the signal put in evidence by ATLAS and CMS is produced by a very special kind of interactions between the protons accelerated by the LHC. These are "vector boson fusion" processes, whereby it is not the protons or its constituents that come in direct contact, but rather, each proton emits a W boson, and it is the latter pair which fuse together, give rise to a Higgs particle.
I reported here a few days ago about a very nice challenge issued by the ATLAS experiment: find Higgs boson decays to tau lepton pairs in a sample containing signal as well as background events, using a training sample with correct signal and background labels per each event.

The challenge consists of solving a typical classification problem in a highly multidimensional space (30 dimensions) better than all other participants - the metric to judge being an "approximate median significance" of the subset of events that the user classifies as "signal". This is given by the formula

AMS = sqrt {2 * [(s+b+10) * log(1 + s/(b+10)) - s] }
I am spending the week in the pleasant resort of La Biodola, in the Elba island. Elba is a beautiful island just off the coast of Tuscany. Here Napoleon was exiled after his abdication in 1814 (he arrived here on May 30th). Exactly 200 years later, 100 Italian researchers have decided to exile themselves here to discuss the future 10 years of accelerator-based experiments, to understand where to "put their money", or better their research activities and efforts.