Lisa Grossman, reporter
The internet is hungry for news about neutrinos, and it is being fed ? even if that news is, well, old.
Last week, the OPERA collaboration announced the results of new tests that bolstered their stunning result, first announced in September, that neutrinos go faster than light.
The saga of those Einstein-defying neutrinos appeared to take a dramatic turn today, with a flood of news stories reporting that a second experiment in the same lab showed that the subatomic particles are obeying the speed limit after all.
Time and repeated experiments will tell which group is right. But it bears mentioning that the results of the second experiment are not new. A number of outlets ? including New Scientist ? reported it a month ago after a paper about it was posted online.
The feeding frenzy seems to have been sparked by a press release that landed in our inboxes this morning from the UK Science Media Centre, "an independent venture working to promote the voices, stories and views of the scientific community to the national news media when science is in the headlines". The centre offered a comment from physicist Jim Al-Khalili of the University of Surrey, who, when the initial news broke in September, had publicly vowed to eat his boxer shorts on live television if the result held up.
When the news broke on Friday that the OPERA team had redone their experiment with a new and improved particle beam, and the troubling neutrinos didn't go away, Al-Khalili's inbox apparently overflowed with people demanding he follow through. As he blogged on Friday:
"I have been prompted to write this blog, instead of chilling with a glass of wine after a busy week and watching a movie on TV, because of the flurry of comments via email and Twitter that I have received today regarding the latest news from the Opera neutrino experiment... Now, many people mistakenly believe that this second repeated experiment is the confirmation needed for me to fetch the ketchup."
He went on to explain how a pair of theorists at Boston University, Andrew Cohen and Nobel laureate Sheldon Glashow, predicted on 29 September ? less than a week after OPERA announced their original results ? that such speedy neutrinos should leave a tell-tale trail of particles in their wakes. As we wrote at the time:
In the paper, Glashow and Cohen point out that if neutrinos can travel faster than light, then when they do so they should sometimes radiate an electron paired with its antimatter equivalent ? a positron ? through a process called Cerenkov radiation, which is analogous to a sonic boom. Each electron-positron pair should carry away a large chunk of the neutrinos' energy: Cohen and Glashow calculated that at the end of the experiment, the neutrinos should have had energies no higher than about 12 gigaelectronvolts. But OPERA saw plenty of neutrinos with energies upwards of 40 GeV.
The ICARUS collaboration, which has been studying the same beam of neutrinos as OPERA since last year, looked for just that sort of radiation, and didn't find any. They put out a paper on 17 October saying: "Our results therefore refute a superluminal interpretation of the OPERA result." Again, we and others wrote about it at the time.
Al-Khalili is not a member of the OPERA or ICARUS teams, and the memo from the Science Media Centre was presented as an "expert reaction". But many in the media reacted as if the ICARUS paper was hot off the press, even as they linked to an updated preprint dated 22 October and physics blogs from the same week.
It just goes to show how desperate we all are to hear something definitive about these neutrinos. Stay tuned to our ultimate guide to neutrino news.
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