Physics Blog Number 4 - September 30, 2011


Higgs boson

    The Higgs is finding it harder to hide (http://physicsworld.com/cws/article/news/46636) .  The lates results from the LHC point toward the mass region "130–150 GeV".   Hmmm.  I'm no particle physicist, but it does it seem peculiar that the Higgs should be lighter than the top quark? Of course, none of the results point toward the Higgs, but point to regions where it is not.  It's a statistical game, so that the physicists must feel that they understand the background extremely well, in order not to get a false positive.
    One neat side effect of all these high energy (7 TeV) collisions is that the standard model is being re-confirmed.  In particular, there seems to be only three generations of quarks, and my favorite: "Quarks also remain point-like at the energies probed so far."  If this is true, then it may spell the End of Physics. Of course, there are always discoveries to be make in nonlinear physics - superconductivity, chaos, biology - but what does it mean if we have probed as far as we can? Note: they haven't seen any hint of supersymmetric particles yet, at least lighter than 900 GeV.

Faster-than-light neutrinos?

    The big news this week is, of course, the faster-than-light neutrinos as measured by the OPERA group in Italy.  Regardless of the correctness of their claim, I think that the biggest no-no is the fact that they held a press conference rather than submitting their work to a refereed journal.  See here for others' thoughts along the same lines. When groups do this, they set themselves up for embarassment.  I can think of two other cases in the recent history of physics where different choices were made by the participants.
    First, cold fusion in 1989.  I was a graduate student at UCLA at the time, and as I recall, Pons and Fleischmann submitted a paper on their experiment.  Steve Jones, who also worked on "muon-catalyzed fusion," was one of the reviewers.  (He wrote a Scientific American article on the subject in 1987 - see here.) Since their work was so similar, all parties met and agrees to have their papers published simultaneously.  However, egged on by the University of Utah (where Pons was), Pons and Fleischmann decided to hold a press conference and "steal the thunder."  Needless to say, the entire stunt backfired.  Physics labs around the world dropped what they were doing and tried to replicate the "excess energy" that was seen.  Nobody did.  The moral of the story is that you submit your results for peer review before going public.
    The other related incident ocurred in 1974, also in the high-energy physics community.  Sam Ting at Brookhaven National Lab led a team investigating high energy collisions.  In one experiment, they saw evidence of an unknown particle that 'lived' for 1000 times longer than any other known particle.  This was rather strange - in fact, it was unbelievable.  So they didn't publish it because it went against accepted theory and it was hard to believe.  However, after discussing the experiment with other physicists at conferences, they found that Burton Richter and his team at SLAC (in Stanford) were also seeing the same thing.  Now that they had independent confirmation, both groups decided to publish.  The particle they found was the famous J/psi particle, a bound state of a charm quark and an anticharm quark (also known as "charmonium").  It was the discovery of charm.  This is what the CERN group needs to do: find independent confirmation.  This does not mean to do the experiment again with the same people; it means finding another group to use different methods to confirm their findings.  Already a group at FermiLab is doing just that.
    In a talk yesterday at the University of Central Florida, Tristan Hubsch suggested that another problem is that many physicists are forced into making crazy statements, like, "If this is proved correct, then all of physics will have to be reworked." (In fact, I heard that crazy guy, Michio Kaku, make similar ridiculous assertions last night on the NPR show "On Point.")  Hubsch suggests that it's not such a horrible thing.  There are severl theories that have methods in which neutrinos can travel faster than the speed of light.  Of course, until now, nobody thought those mathematical theories applied to our universe.  But perhaps they do.
    A final thought.  Sheldon Glashow, Nobel Laureate, has published a paper on the arXiv preprint server claiming that the neutrinos should have lost energy.  That is, if they were traveling superluminally they would have emitted electron-positron pairs.  Using this analysis, they "refute the superluminal interpretation of the OPERA result."