Sunday, January 11, 2015
The ANITA balloon-born neutrino detection experiment has just finished its third flight. It flew for 22 days, 9 hours, during which time it circled Antarctic about 1 1/3 times.
ANITA floats high in the atmosphere (usually more than 100,000 feet), while it's 32 horn antennas look for radio waves from neutrino interactions in the Antarctic ice. Because of its height, it can scan an enormous volume of ice, out to the horizon, up to 600 km away. However, because of the distance to the interactions, it has a pretty high energy threshold, above 10^19 eV (roughly 100 times higher than ARIANNA). In its previous two flights, it did not see any neutrino interactions, but it did set some of the best current limits on ultra-high energy cosmic neutrinos. They also observed pulses which they attribute to coming from cosmic-ray air showers.
For the third (and what was planned to be the last) flight, the collaboration made a number of improvements to increase the experiments sensitivity, including the addition of a large, lower-frequency antenna, which be stowed for take-off and then released in-flight to hang below the balloon.
This flight was shorter than the previous flights; the second (ANITA-II) flight lasted 31 days, while the first flight was 35 days. NASA has a nice web-page showing the ANITA flight track. So, although the detector may have been more sensitive, this flight is unlikely to dramatically improve the overall ANITA sensitivity.
Katie Mulrey has written a couple of nice blog posts about the ANITA pre-flight preparations. They are here and here
I'm eagerly looking forward to hearing more about how the flight went, and how the data looks.
Tuesday, January 6, 2015
Big Bird made the American Physical Society list of the top ten physics news stories in 2014. The details were published our article extending the high-energy contained event search to 3 years of data (as discussed in a previous post).
We also published a number of interesting articles on other subjects: cosmic neutrinos at lower energies, dark matter, neutrino oscillations, the search for magnetic monopoles, and other subjects.
Francis Halzen and I have written an article for the CERN Courier summarizing what IceCube has learned so far, and discussing future plans with HEX and PINGU. I'm happy to report that the article became the cover story for the December, 2014 issue. It is available here; I may be biased, but I think it's a nice article, well worth reading.