Physics

The CDF collaboration, which runs one of the two proton-antiproton collider experiments at the Fermi National Accelerator Laboratory since the early eighties, has published hundreds of scienticif papers in the course of its 25 years of operation. I believe the number has abundantly surpassed the half-thousand mark, but I am unaware of its exact entity. Computing the exact number is made complicated by the fact that the publications are scattered in many different magazines: Physical Review Letters, Physics Review, Nuclear Instruments and Methods, etcetera. Plus, there are proceedings to…

On March 8th, international women day, the CMS experiment at CERN will be run almost entirely by women. 32 of the 34 shifts needed to run our experiment will be covered by women scientists of our Collaboration - which counts 588 women overall. I think this is great news and a very good idea. 588 women scientists are quite an impressive force! And believe me, most of them really do kick ass!!

Yesterday somebody asked me here if I could explain how does a muon really decide when and how to decay. I tried to answer this question succintly in the thread, and later realized that my answer, although not perfectly correct in the physics, was actually not devoid of some didactic power. So I decided to recycle it and make it the subject of an independent post. Before I come to the discussion of how, exactly, does a muon choose when and how to decay, however, let me make a few points about this fascinating particle, by comparing its phenomenology to that of the electron. Muons versus…

The CDF collaboration has recently released new results from a search for what is probably the clearest signature of Higgs boson decay: pairs of high-mass photon candidates. I am very glad to see this new analysis out for publication, since so far only DZERO, CDF's competitor at the Tevatron, had produced results on this particular final state. The reason why CDF took it easy is that at the Tevatron this is really not the most sensitive way to search for a standard model Higgs boson: the Higgs decay to a pair of photons is predicted to be quite rare -only one in a thousand or so; and the…

    The “New Rules for Time Travel ” and Sean Carroll’s Gate   Marshall Barnes, R&D Eng AET RaDAL United States of America February 16, 2010 (NEW! As of 3/4/2010, see special *note about Sean Carroll after References at the bottom...)     Abstract   This paper will deconstruct and analyze the closed time-like curve examples of  Sean Carroll as he wrote them in the March 2010 cover story for Discover Magazine in relation to issues of entropy, determinism, and time travel paradoxes. I will then reveal the actual nature of how…

"We were not yet prepared to claim that we had found a new charged lepton, but we were ready to claim that we had found something new. To accentuate our uncertainty I denoted the new particle by U for unknown in some of our 1975-1977 papers. The name came later. This name was suggested by Rapidis, who was then a graduate student and had worked with me in the early 1970s on the problem. The letter is from the Greek for "third" -the third charged lepton". Martin Perl, The Discovery of the Tau Lepton, in "The Rise of the Standard Model", Cambridge Univ. Press 1997.

Science Fun With A Hot Drink Here is a most enjoyable physics experiment that anyone can do almost anywhere. You will need: 1 hot drink,1 comfortable chair,1 table or desk. You will not need: 1 thermometer. Having made yourself a nice steaming hot drink, sit in the chair and put the cup on the table.You may, if preferred, put the cup on the table and then sit down.  This will in no way affect the validity of the results.  However, if you sit on the table and put the chair on the cup you are likely to invalidate the entire experiment, so stop being so silly! Wait until the slosh is…

The T2K (Tokai-to-Kamioka) project has tracked their first neutrino, one of the least understood particles in the universe.  The detection of the neutrino as it passed 185 miles from the East to the West of Japan means the study of the mysterious phenomenon of neutrino oscillations may shed more light on the role of the neutrino in the early universe, or perhaps even help answer questions about why there is more matter than anti-matter in the universe. "Neutrinos are the elusive ghosts of particle physics, T2K spokesperson Takashi Kobayashi said."They come in three types, called electron…

We live in an expanding universe. Distant galaxies move away from us, and these galaxies see us moving away from them. If we reverse time and trace back this expansion, it follows that the universe has evolved from a dense primeval/primordial state. The big bang concept summarized in three sentences. Sounds easy? History shows that the concept of a big bang is difficult to swallow. That even holds for the brightest minds in the history of science. For thousands of years, mankind has struggled with the basic question “Does the universe have a beginning?” In hindsight, the answer was up for…

One of the few physics measurements that the LHC experiments are already in the position of producing, with the week-worth of proton-proton collision data they have collected last December, is that of the Bose-Einstein intereference between identical bosons. I hope I will have a more thorough discussion of this intriguing quantum-mechanical effect soon, when the experiments will have produced results on it: ALICE, the experiment built to study nuclear collisions, has already shown the effect at a CERN public meeting two days before Christmas (see figure at the bottom of the post), so it is…