Neutrino detector block

A close look at the assembly of the NOvA near detector reveals a massive yet meticulous process.

Photo by Reidar Hahn, Fermilab

Photo by Reidar Hahn, Fermilab

Sarah Witman
When the sun rises over Fermi National Accelerator Laboratory each morning, it beams down on a relatively unchanging landscape: 10 square miles of prairie dotted with various lab buildings. On most days, not much stirs that early in the morning. Some days, though, the sunrise coincides with a big event at Fermilab: NOvA block moving day.
NOvA is Fermilab’s largest neutrino experiment. It features two large detectors, one of which is located at Fermilab and is made up of eight 23,411-pound plastic blocks each measuring about 15 feet high, 15 feet wide and 6 feet thick.
Those involved in a NOvA block moving day wake up very early so they can complete the move before the end of the day. They try to avoid what would be a race against the sun since their work is meticulous and there is no room for error.
“These blocks are not redundant,” says Fermilab scientist Ting Miao, the project’s manager. “If one gets damaged in the move, there’s no way to replace it—by design. It’s really a one-shot business.”…
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Video: NOvA,Building a Next Generation Neutrino Experiment

Neutrino ‘flavour’ flip confirmed

An important new discovery has been made in Japan about neutrinos

neutrinosThese are the ghostly particles that flood the cosmos but which are extremely hard to detect and study.

Experiments have now established that one particular type, known as the muon “flavour”, can flip to the electron type during flight.

The observation is noteworthy because it allows for the possibility that neutrinos and their anti-particle versions might behave differently.

If that is the case, it could be an explanation for why there is so much more matter than antimatter in the Universe.

Theorists say the counterparts would have been created in equal amounts at the Big Bang, and should have annihilated each other unless there was some significant element of asymmetry in play.

“The fact that we have matter in the Universe means there have to be laws of physics that aren’t in our Standard Model, and neutrinos are one place they might be,” Prof Dave Wark, of the UK’s Science and Technology Facilities Council (STFC) and Oxford University, told BBC News.

The confirmation that muon flavour neutrinos can flip, or oscillate, to the electron variety comes from T2K, an international collaboration involving some 500 scientists.

The team works on a huge experimental set-up that is split across two sites separated by almost 300km.

At one end is the Japan Proton Accelerator Research Centre (J-Parc) located on the country’s east coast.……
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Neutrinos from outer space open new eye in the sky

Space neutrinos found in Antarctica (Image: Sven Lidstrom/NSF)

Space neutrinos found in Antarctica (Image: Sven Lidstrom/NSF)

Fancy seeing the sky in neutrino? Supermassive black holes and enormous stellar explosions may give up their secrets now thatneutrinos from space can be detected.

The South Pole IceCube neutrino observatory has seen a handful of ghostly high-energy neutrinos that almost certainly came from outer space, opening up the skies for neutrino astronomy.

“We are witnessing the birth of this field,” says Dan Hooper, a theoretical astrophysicist at Fermilab in Batavia, Illinois, who is not a member of IceCube.

Until now, the only space neutrinos definitively detected came from the sun and a 1987 supernova explosion in the Large Magellanic Cloud.

Last month, the IceCube collaboration published news of the detection of two high-energy neutrinos, each with an energy of about one petaelectronvolt. These neutrinos, discovered by accident a year ago and nicknamed Bert and Ernie, prompted the collaboration to go back and look at their data in more detail.

Flavour shift

The new analysis, reported today at the IceCube Particle Astrophysics symposium at the University of Wisconsin-Madison, has raised the stakes….


Neutrinos, the standard model misfits

For years, scientists thought that neutrinos fit perfectly into the standard model. But they don’t. By better understanding these strange, elusive particles, scientists seek to better understand the workings of all the universe, one discovery at a time.
by Joseph Piergrossi

Neutrinos are as mysterious as they are ubiquitous. One of the most abundant particles in the universe, they pass through most matter unnoticed; billions of them are passing harmlessly through your body right now. Their masses are so tiny that so far no experiment has succeeded in measuring them. They travel at nearly the speed of light—so close, in fact, that a faulty cable connection at a neutrino experiment at Italy’s Gran Sasso National Laboratory in 2011 briefly led to speculation they might be the only known particle in the universe that travels faster than light.
Physicists have spent a lot of time exploring the properties of these invisible particles. In 1962, they discovered that neutrinos come in more than one type, or flavor. By the end of the century, scientists had identified three flavors—the electron neutrino, muon neutrino and tau neutrino—and made the weird discovery that neutrinos could switch flavor through a process called oscillation. This surprising fact represents a revolution in physics—the first known particle interactions that indicate physics beyond the extremely successful Standard Model, the theoretical framework that physicists have constructed over decades to explain particles and their interactions.
Now scientists are gearing up for new neutrino studies that could lead to answers to some big questions:

If you could put neutrinos on a scale, how much would they weigh?
Are neutrinos their own antiparticles?
Are there more than three kinds of neutrinos?
Do neutrinos get their mass the same way other elementary particles do?
Why is there more matter than antimatter in the universe?

The answers to these questions not only offer a window on physics beyond the Standard Model, but may also open the door to answering questions about the universe all the way back to its origins….
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Scientists place new limits on sterile neutrinos

Close-up of the tank of the MiniBooNE neutrino experiment before it was filled with ultraclean mineral oil. Image: Fermilab

Two Fermilab experiments have put new boundaries on a search for a possibly undiscovered type of neutrino, leaving prior measurements unexplained.

So far, scientists have observed three types, or flavors, of neutrino: the electron neutrino, the muon neutrino and the tau neutrino. But physicists have seen hints that this may not be the whole picture.

Expanding the neutrino clan would have far-reaching effects, said Los Alamos physicist Warren Huelsnitz of Fermilab’s MiniBooNE experiment. “If we discovered a new type of neutrino, it would expand our understanding of the Standard Model,” he said. “It would cause cosmologists to recalculate their predictions of the early universe.”

One of scientists’ first clues that neutrinos were more than what they seemed came when they measured fewer electron neutrinos than expected streaming from the sun. A deficit also appeared when proton decay experiments measured the number of muon neutrinos produced in the Earth’s atmosphere. Physicists eventually discovered that the missing neutrinos were simply in disguise; they had oscillated into another flavor of neutrino as they traveled.

Flavor oscillations solved the solar and atmospheric neutrino problems, but subsequent experiments have come up with more puzzling results. The Liquid Scintillator Neutrino Detector experiment at Los Alamos National Laboratory found an excess of electron antineutrinos coming from a muon antineutrino beam at short range. Reactor and radioactive-source experiments have found similar-seeming deficits of electron antineutrino and neutrino events, respectively.

If the excess and deficits were due to oscillations, that could point to the existence of at least one other, intermediary type of neutrino, to which muon neutrinos would need to oscillate before becoming electron neutrinos, Huelsnitz said. “There would have to be a new type of neutrino involved as a go-between,” he said.

The new type of neutrino would be sterile – not affected by the weak nuclear force like other types of neutrinos – and therefore would not interact in today’s neutrino detectors.

The MiniBooNE experiment at Fermilab has found an excess of electron antineutrino events that may be related to the LSND result. But when MiniBooNE scientists searched for a corresponding deficit in muon neutrinos or antineutrinos, they found no evidence of one.

This month, they updated their results in partnership with another short-baseline neutrino experiment, SciBooNE. Once again, they found no shortage of muon antineutrinos.

The new result put tighter parameter constraints on the possibility of sterile neutrinos. But the excess of electron antineutrinos at Los Alamos and Fermilab remains a mystery.
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ICARUS: Neutrinos Travel At Light Speed. Period.

By Tommaso Dorigo

Little less than one year ago the world of fundamental physics was shaken by the bold claim of the OPERA collaboration, which produced a measurement of the time of flight of neutrinos traveling underground from Geneva to the Gran Sasso mine in central Italy. The beam of neutrinos, produced by the CERN SpS proton synchrotron, was observed to produce interactions in the large mass of the OPERA detector with about 60 nanosecond anticipation with respect to what would be expected for a particle traveling at exactly the speed of light (2439096.1+-0.3 nanoseconds, since the flight path is of 731221.95+-0.09 meters).

Following the CERN announcement of the OPERA result physicists around the world busied themselves with pointing out several issues with the measurement, among which the statistical analysis of the data, the precise measurement of several delays in the detection process, and other hardware components, and remained generally quite cold….

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