Recommended by us: "MicroBooNE, in 3-D"

Tingjun Yang (left) and Wesley Ketchum lead the effort to develop new 3-D reconstruction 
software for the MicroBooNE experiment. Here they stand inside the MicroBooNE 
time projection chamber.Photo: Reidar Hahn

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Imagine your job is to analyze the data coming from Fermilab's MicroBooNE experiment. 

It wouldn't be an easy task. MicroBooNE has been designed specifically to follow up on the MiniBooNE experiment, which may have seen hints of a fourth type of neutrino, one that does not interact with matter in the same way as the three types we know about. The big clue to the possible existence of these particles is low-energy electrons.

But that experiment could not adequately separate the production of electrons from the production of photons, which would not indicate a new particle. MicroBooNE's detector, an 89-ton active volume liquid-argon time projection chamber, will be able to. To take advantage of this, every neutrino interaction in the chamber will have to be examined to determine if it created an electron or a photon.

And there will be a lot of interactions to study — the MicroBooNE collaboration expects to see activity in their detector once every 20 seconds, including nearly 150 neutrino interactions each day.

If all goes to plan, human operators won't have to worry about any of that. When MicroBooNE switches on next summer, it will sport one of the most sophisticated 3-D reconstruction software programs ever designed for a neutrino experiment.

According to Wesley Ketchum and Tingjun Yang, two postdocs leading the software development team at Fermilab, MicroBooNE's computers will be able to accurately reconstruct neutrino interactions and automatically filter the ones that create electrons. The key to accomplishing this lies in the design of the time projection chamber.

Continue to read on Fermilab Today 

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Recommended by us: "Sterile-neutrino hunt gathers pace at Gran Sasso"

The Borexino detector at Gran Sasso: the SOX experiment will soon be using it to look for sterile neutrinos. (Courtesy: Borexino collaboration)

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Much-debated results suggesting the existence of a fourth kind of neutrino, described as sterile, are to be put to the test in a new experiment under Italy's Gran Sasso mountain. The physicists who have devised the experiment say that by using an existing solar-neutrino detector they can carry out an inexpensive yet thorough search for the hypothetical sterile neutrino.

Neutrinos are chargeless, almost massless subatomic particles that interact with ordinary matter only via the weak nuclear force. As a result they can pass through vast amounts of material undisturbed. To study them, physicists build huge detectors – the idea being that a large number of target nuclei will result in a few neutrino collisions that can be detected.

If they exist, then sterile neutrinos would be even more difficult to detect because they probably would not interact with ordinary matter at all – only with other neutrinos. They would do so via "oscillation", a well-established phenomenon in which ordinary neutrinos transform and re-transform continually from one of three flavours – electron, muon and tau – to another as they travel. Likewise, ordinary neutrinos would oscillate into sterile neutrinos and back again but probably over much shorter distances than those typical of normal neutrino oscillation.

Continue to read on http://physicsworld.com

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Recommended by us: CERN and Sterile Neutrinos

CERN Set to Study Sterile Neutrinos

by Edwin Cartlidge on 5 February 2013

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A new experimental facility to detect a hypothetical particle that many physicists think probably doesn't exist could be up and running at the CERN laboratory near Geneva, Switzerland, within 3 years, assuming that the lab's member states approve spending roughly $110 million to build it.

The sterile neutrino, if it exists, would be an obscure variety of an already otherworldly subatomic particle. Ordinary neutrinos, which have no charge and almost no mass, come in three varieties: electron, muon, and tau. They are very hard to detect because their interaction with ordinary matter is extremely feeble, but over the years physicists have detected enough of them to observe that as they travel through space they can "oscillate" from one flavour to another.

This oscillation phenomenon, which means that neutrinos cannot be entirely massless, has been confirmed by many different experiments. But one such experiment produced results at odds with the rest. That was the Liquid Scintillator Neutrino Detector (LSND) at the Los Alamos National Laboratory in New Mexico, which in data acquired between 1993 and 1998 showed muon antineutrinos to be oscillating into electron antineutrinos far more readily than expected.

(Continue to read on news.sciencemag.org)

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