Zippy neutrinos: Yet another challenge–no Cerenkov radiation
Cerenkov radiation in the core of a nuclear reactor
This blog probably shouldn’t note every zig nor zag in the saga of the superluminal neutrino hypothesis. (No, that’s not the name of a new episode of “The Big Bang Theory.”) But this is a zag from a well known figure who is hard to ignore, Nobelist Sheldon Glashow.
The problem he sees with the neutrino experiment is that the particles fired from CERN to a detector in Italy did not give off something called Cerenkov radiation. That’s what other particles do when they outpace light in a medium that slows photons below lightspeed. Light, as not everyone knows, travels at lightspeed only in a vacuum, but something as simple as water can slow it down, even as other particles pass the photons by. When those particles go faster than light, they give off flashes of energy, the Cerenkov radiation. That may be what led to the popular misconception that radioactivity makes things glow.
Devin Powell explains at Science News with a nice quote from Glashow’s co-author, Andrew Cohen, writing in Physical Review Letters: “I would be ecstatic to see some kind of new physics coming from this experiment. It’s just hard to accommodate that, given this [lack of] radiation.”
-Boyce Rensberger
October 19th, 2011 at 6:09 pm
My colleague Davide Castelvecchi also covered this story several weeks ago: http://blogs.scientificamerican.com/degrees-of-freedom/2011/10/02/superluminal-neutrinos-would-wimp-out-en-route/
October 19th, 2011 at 7:02 pm
Ah. Thanks for letting all of us know.
Looks like your colleague found it when the paper was posted online, and Science News pegged their take to the upcoming publication on paper.
October 19th, 2011 at 7:43 pm
What George said.
But also, the quote from Cohen looks like it’s from an interview, not the paper. Anything so colorful would doubtless have been banished before publication in PRL.
October 19th, 2011 at 11:14 pm
I think you’re right about an interview. I worded my sentence poorly. No stuffy journal would allow such human feelings into its pages.
October 20th, 2011 at 9:38 am
Nice post, and here’s a minor remark, not quite a correction. Most historic references say the once-common method of making glow-in-the-dark watch dials and other consumer items with coatings that included the tribute to radiation itself, the element radium, inspired the popular glow-in-the-dark myth. Think Marie Curie. Radium does not by itself glow. Neither does any other radioactive substance (I think) that’s sitting in a vacuum by itself. However if such a coating includes the right phosphors or more precisely scintillators or fluors they absorb some of the alpha particles and release their energy as visible light. Some expensive watches (now I’m relying on Wikipedia) still use radium or another radioisotope, tritium, to energize such things. Cerenkov radiation does, for sure, reinforce the misconception.
October 20th, 2011 at 9:57 am
Welcome back, Charlie.
October 20th, 2011 at 4:27 pm
There was a new twist on the Cerenkov radiation subplot today at Nature (I had seen it on Dorigo’s blog) http://www.nature.com/news/2011/111020/full/news.2011.605.html
It’s hard for editors not to have reporters covering every twist and turn of this tale when stories about them pick up so many clicks and comments on our sites (assuming others are similar). With more than 80 preprints online responding to OPERA there’s also plenty to choose from. The majority are positive, wacky ways of having it be true. Still there are a handful of take-downs, each of which has had its share of stories. I think it is justified given the original coverage, to jump on some of these attempted take-downs, they may not all be right but at least they are people putting their reputations behind a possible problem.
By the way these pictures of the September 23 seminar at CERN give an idea of the interest http://cdsweb.cern.ch/record/1384483