Physics

The 2012 measurements of the Higgs boson, performed by ATLAS and CMS on 7- and 8-TeV datasets collected during Run 1 of the LHC, were a giant triumph of fundamental physics, which conclusively showed the correctness of the theoretical explanation of electroweak symmetry breaking conceived in the 1960s. The Higgs boson signals found by the experiments were strong and coherent enough to convince physicists as well as the general public, but at the same time the few small inconsistencies unavoidably present in any data sample, driven by statistical fluctuations, were a stimulus for fantasy…

The physics of nanometer sized bubbles is mysterious and controversial. Gas bubbles in liquids are unstable.[2] Also large air bubbles in water are not stable. Even if we keep them somehow from rising to the surface and popping, the surface tension of the bubble itself presses the air out of the bubble and into the liquid! The physicist calls this ‘Laplace pressure’.[3] We do not notice this with large bubbles. However, with a nanobubble, the Laplace pressure dissolves it in a few micro seconds. If you have multiple bubbles, the smaller ones get smaller and the bigger ones bigger. This is…

800x600 Dirac CP-violating phase from deviation of neutrino mixing from geometric bimaximal approximation     Since by evidence the leading bimaximal approximation to neutrino mixing obeys the 3-space Euclidean geometry Metric Equation, its necessary and sufficient condition is Theta_13 = 0. After the experimental Theta_13 results of Daya Bay and others the world mean values for neutrino mixing angles are     Theta_12 = (33.7+-1.1)^o, Theta_23 = (40.7+-1.7)^o, Theta_13 = (8.8+-0.4)^o,   (1) as estimated by e. g. F. Gapozzi et al, arXiv:1601.07777, and…

Next Monday, the Italian city of Rome will swarm with about 700 young physicists. They will be there to participate to a selection of 58 INFN research scientists. In previous articles (see e.g. here, here, here, here, here, here, and here) I have offered some training questions, based on my own experience of similar selections and on how I would myself structure an exam if I were in the selection committee.Of course I offered those tests without any ambition to accurately represent the kind of questions my young colleagues will really have to face, and with a big disclaimer. I feel that…

Particle physics conferences are a place where you can listen to many different topics - not just news about the latest precision tests of the standard model or searches for new particles at the energy frontier. If we exclude the very small, workshop-like events where people gather to focus on a very precise topic, all other events do allow for the contamination from reports of parallel fields of research. The reason is of course that there is a significant cross-fertilization between these fields. Scientists often hop from one to the other fields as they develop their careers. It is not…

Gino Bolla was an Italian scientist and the head of the Silicon Detector Facility at Fermilab. And he was a friend and a colleague. He died yesterday in a home accident. Below I remember him by recalling some good times together. Read at your own risk.  Dear Gino,    news of your accident reach me as I am about to board a flight in Athens, headed back home after a conference in Greece. Like all unfiltered, free media, Facebook can be quite cruel as a means of delivering this kind of information, goddamnit. I did shed a few tears for you under the sunglasses I was quick to put…

800x600 Complementarity relation between CP-violating phase and neutrino mixing reactor angle     It should be a basic physics cause for neutrino mixing deviation from CP-conserving geometric bimaximal pattern -- that cause is CP-violation. It is interesting that this idea can be partly quantified by a simple complementarity relation between the two special angles in neutrino mixing matrix – neutrino reactor Theta_13 angle and Dirac CP-phase angle (denoted as (13) and CPph respectively):              …

The book "Anomaly! Collider Physics and the Quest for New Phenomena at Fermilab" is going to press as we speak, and its distribution in bookstores is foreseen for the beginning of November. In the meantime, I am getting ready to present it in several laboratories and institutes. I am posting here the coordinates of events which are already scheduled, in case anybody lives nearby and/or has an interest in attending.- On November 29th at 4PM there will be a presentation at CERN (more details will follow). - On December 13th at 4.45PM at HERA, in Hamburg, I will present a physics seminar where I…

The Italian National Institute for Nuclear Physics offers 20 post-doctoral positions in experimental physics to foreigners with a PhD obtained no earlier than November 2008. So if have a PhD (in Physics, but I guess other disciplines are also valid as long as your cv conforms), you like Italy, or if you would like to come and work with me at the search and study of the Higgs boson with the CMS experiment (or even if you would like to do something very different, in another town, with another experiment) you might consider applying! The economical conditions are not extraordinary in an…

While I do not believe that this series of posts can be really useful to my younger colleagues, who will in a month have to participate in a tough selection for INFN researchers in Rome, I think there is some value in continuing what I have started last month. After all, as physicists we are problem solvers, and some exercise is good for all of us. Plus, the laypersons who occasionally visit this blog may actually enjoy fiddling with the questions. For them, though, I thought it would be useful to also get to see the answers to the questions, or at least _some_ answer.Indeed, many of the…