Today I am back from the 8th edition of the ICNFP conference, which finished yesterday in Kolymbari (Crete). This event is very interesting because of its wide scope, bringing together physicists from quite different fields in a venue that, due to its very relaxing, secluded nature favours post-session discussions and exchanges among the over 250 participants. 

This year I went there as the failed organizer of a session on Machine Learning - there were too few contributions to have a meaningful parallel session, so at the end we distributed the talks to other sessions. I was however not there as a mere spectator in the end, as I got invited at the last minute to fill a hole and give a review talk of the experimental quest for the quarks at the Gell-Mann Memorial session, and my presentation, although produced in only a few days, was very appreciated by the audience, as I found out later.

Among the people I met at ICNFP this year are two remarkable physicists. One of them, Paul Frampton, is known just as much for his interesting new theoretical physics ideas as for a very unfortunate incident that brought him to spend two years time in Argentinian prisons.

The story is retold in excruciating detail in a long article by the NYT magazine, so I will not discuss it here, but if you are curious and in a hurry, basically he got seduced by an imposter who pretended to be a successful bikini model, and convinced to travel to Bolivia and then Argentina to meet her; in Buenos Aires he was given a luggage "of sentimental value" to bring back to Europe. Needless to say, the empty suitcase actually contained 2kg of cocaine. He was found guilty because his phone contained messages that implied he had understood the contents of the suitcase but he had nonetheless tried to board a plane with it.
Update: After I wrote and published the above paragraph, Paul Frampton graciously sent me a forensic report redacted in 2017 by John Olsson, a forensic linguist hired by Paul, which purports to demonstrate he did not send those messages himself. I discuss and publish that report in another post here. I tend to believe that the conclusions of the expert linguist stand.

Bileptons in LHC Data?

Back to Physics, Frampton has several interesting ideas, and he discussed a couple in two of his three talks at the conference. One of these implies the existence of "Bileptons", doubly-charged particles that decay to like-sign leptons. Their introduction, if I understood his talk, comes from hypothesizing a larger group structure than SU(3)C x SU(2)L x U(1) - the latter two subgroups arise from the breaking of another SU(3). 

The benefit of the setup is that it produces anomaly cancellation (a theoretical must, without which the whole quantum field theory of electroweak interactions makes no sense) only if there are exactly three families of elementary fermions, as opposed to the Standard Model, where anomaly cancellation is guaranteed family by family and thus can work with an arbitrary number of quark and lepton families. 

In other words, Frampton's model is "post-predictive" of the observed feature of our Universe to contain, apparently, only three quark and lepton families. The electroweak constraints coming from the group structure also imply that these resonances should have a mass larger than 800 GeV and smaller than 4 TeV. Frampton is evidently enthusiastic of his pet theory, so much so that he says that the odds that it be correct are "about 80%". 

ATLAS is allegedly searching for these particles in their data, and Paul is very eager to know the results, as he insists that backgrounds should amount to less than one event, while the predicted cross sections of the pair-production of Bileptons should range from several hundred to a few femtobarns, putting the whole model in the testable area with Run 2 data. Who knows? If they are roses, they will flourish.

A New Avenue to Light Dark Matter Searches and Geological Prospections

Another physicist, who has spent a lot of time in molecular biology and has a broad knowledge of geology as well, is Andrzey Druckier. He gave two different talks where he fascinated his audience with his bold, new experimental ideas. In one talk he discussed a bolometric detector that can detect dark matter coherent scattering off nuclei by employing very exotermic reactions - almost bomb-like - in composite molecules thanks to the transition from superconducting to normal conducting mode, and therefore could be sensitive to light dark matter and beat all existing technologies there. He did not give a lot of detail of this idea, but it is clear that it is a new avenue clearly worth pursuing. He has a pending patent request for his design here.

Druckier also mentioned that the light (M<5 GeV) region of DM is the most interesting as present limits could be very overestimated in their sensitivity, due to the experimental groups possibly overestimating the velocity distribution of the DM in our vicinity. He claims the Gaia satellite, with its precise measurement of velocity fields of stars in our galaxy, will soon clarify the situation. He argues that because of the above he believes the DAMA dark matter signal is genuine, but that only his technology can produce a directional measurement of the same signal. He is, in fact, and with his group he has been trying to construct a 5kg demonstrator of a "spaghetti" detector that could show its sensitivity by being brought close to a running reactor. 

The idea of this technology for dark matter searches is that it is liable to be used for background-free measurements if you produce a fully automated detector and lower it in the Mariannes trench, where backgrounds are extremely low (the peculiarity and dangerous nature of the detector make it unsuitable to be placed in underground mines). But the technology could also be used, crucially, for geological prospections, by constructing a movable detector that can be sensitive to the U and Th decays, as these elements are contained with much higher concentration in ores rich with rare earths or gold.

The Boldest Idea: Paleo-Detectors!

But what I fould the most interesting idea of his was the one he discussed in the last talk of the conference. He talked of "paleo-detectors". The idea here is that the USSR has dug very deep holes in the Earth crust to do geological prospections, and the excavated material can be used for searches of tracks of dark matter-nuclei interactions with electron microscopy. In particular, marine sea evaporates like NaCl are known to have very low contamination from U and Th, the two bad beasts of background contamination in sensitive dark matter searches.

The other point is that the deeper one excavates, the older is the material, so by taking sea salt samples coming from 10km below the surface one is looking at stuff that is one billion years old. These crystals could therefore have been exposed to huge integrated fluxes of DM particles. He explained there is no chance to have a directional measurement, but that nonetheless the distinction of DM interaction from all other backgrounds should be very easy to see, as inhomogeneous materials allow the combined measurement of the track ionization and total energy release. Again, far-fetched ideas perhaps, but incredibly interesting if you ask me. I do hope to see this being carried out one day!


Tommaso Dorigo is an experimental particle physicist who works for the INFN at the University of Padova, and collaborates with the CMS experiment at the CERN LHC. He coordinates the European network AMVA4NewPhysics as well as research in accelerator-based physics for INFN-Padova, and is an editor of the journals Reviews in Physics and Physics Open. In 2016 Dorigo published the book “Anomaly! Collider physics and the quest for new phenomena at Fermilab”. You can get a copy of the book on Amazon.