NOvA and Neutrinos
Yesterday’s Grauniad blog post by Jon Butterworth about neutrino physics reminded me that I forgot to post about an important milestone in the development of the NOvA Experiment which involves several members of the Department of Physics and Astronomy in the School of Mathematical and Physical Sciences here at the University of Sussex. Here’s the University of Sussex’s press release on the subject, which came out a couple of weeks ago.
The NOvA experiment consists of two enormous particle detectors, one at the Fermi National Accelerator Laboratory “Fermilab” near Chicago and the other in Minnesota. The neutrinos are actually generated at Fermilab; the particle beam is then aimed at the detectors the, one near the source at Fermilab, and the other in Ash River, Minnesota, near the Canadian border. The particles, sent in their billions every couple of seconds, complete the 500-mile trip in less than three milliseconds.
The point is that the experiment has managed for the first time to actually detect neutrinos through the 500 miles of rock separating the two ends of the experiment. This is obviously just a first step, but it’s equally obviously a crucial one.
Colleagues from Sussex University are strongly involved in calibrating and fine-tuning the detector, which produces light when particles pass through it. Dr Abbey Waldron and PhD student Luke Vinton have developed a calibration procedure that uses known properties of muons to calibrate precise measurements of the neutrinos, which are less well understood. The detector sees 200,000 particle interactions a second, produced by cosmic rays bombarding the atmosphere, and scientists can’t record every single one. Sussex’s Dr Matthew Tamsett has developed a trigger algorithm that searches for events that look like neutrinos among the billions of other particle interactions.
Neutrino physics is an interesting subject to someone like me, who isn’t really a particle physicist. My impression of the field is that was fairly moribund until 1998 when the first measurement of atmospheric neutrino oscillations was announced. All of a sudden there was evidence that neutrinos can’t all be massless (as many of us had long assumed, at least as far as lecturing was concerned). Now the humble neutrino is the subject of intense experimental activity, not only in the USA and UK but all around the world in a way that would have been difficult to predict twenty years ago.
But then, as the physicist Niels Bohr famously observed, “Prediction is very difficult. Especially about the future.”
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In the Dark 
March 12, 2014 at 7:28 pm
Bohr’s observation puts me in mind of the gloriously cynical comment from the Soviet era about historical revisionism: The past can be very hard to predict.
March 12, 2014 at 11:17 pm
Despite the hype about neutrino mass it is still not exactly clear to me why non-0 neutrino mass is interesting and what exactly it tells us about physics beyond standard model.
When evidence for non-0 neutrino mass was seen P. Ramond mentioned (see http://physics.aps.org/stories/v2/st10/neutrinoquotes.html)
this provides “additional” evidence for low energy supersymmetry.
So why the heck haven’t we seen any evidence for supersymmetry at LHC
March 12, 2014 at 11:37 pm
I think your quote about “moribund until 1998” is unfair to the neutrino. From memory, there was the experimental discovery of the neutrino by Reines & Cowan 1955, and the demonstration c.1962 that the electron and muon neutrinos are distinct, by Lederman, Schwartz & Steinberger. Then neutral currents from Gargamelle at CERN in 1973, the indirect discovery of the Z which basically confirmed the electroweak theory; this was a result that clearly deserved a Nobel, but never got one. Then in 1987 there were nu’s from SN1987A, and also the confirmation from Kaminokande that the solar neutrino problem was not just an error by the original Davis experiment. In the mid-90’s SAGE and GALLEX gallium detectors showed this was highly likely due to neutrino oscillations, not an error in the solar model (though many particle physicists seemed reluctant to accept that until 1998 and Super-K).
Also, you can add in a couple of famous wrong results, the “30eV electron neutrino mass” c. 1980, and the “17 keV neutrino” to add some confusion.
So, all told I think your “moribund” is unfair.
March 13, 2014 at 12:43 pm
Impressive!
March 13, 2014 at 12:46 pm
Indeed, but not surprising for John Bahcall!
March 13, 2014 at 2:47 pm
“I also like the fact that, on his publication list, while like many he had a numbered list, it also had things like 3a, 3b etc for cases where he gave the same talk at more than one conference and thus had two essentially identical proceedings contributions”
Bet he did it that way *after* he got tenure!
October 6, 2015 at 11:58 am
[…] interests in our Experimental Particle Physics group here at Sussex. You can read a recent post here about an important milestone in the development of the NOvA Experiment which involves several […]