* Astronomy

Tasked to check the finding, MiniBooNE researchers fired a beam of normal matter muon neutrinos at a 12-meter-wide spherical tank of mineral oil 500 meters away. When an electron neutrino strikes a carbon nucleus in the oil, it emits a flash of bluish light. The beam produces electron neutrinos directly at a certain rate; a higher frequency would signal something unanticipated.
The group reported no overall increase in the rate of electron neutrino events for muon neutrinos of different energies, which would have bolstered the LSND case for neutrinos switching flavours.

"We have quite conclusively ruled out that model for what might be going on" - Physicist Janet Conrad, Columbia University, spokesperson for the MiniBooNE team.

But there are other, more exotic models that still have to be checked, says co-spokesperson William Louis of LANL, who worked on LSND.

"That is the $64,000 question. Are the MiniBooNE results consistent with LSND, and is the LSND excess a real signal?''

The team has begun running the experiment with antineutrinos to rule out other possibilities, such as a slight asymmetry between matter and antimatter.
The group did spot an odd uptick in the number of electron neutrinos at lower energies369 events instead of 273. But Louis says the significance of that is unclear. It could mean that physicists have overlooked a subtle detail in the experiment or miscalculated the rate at which neutrinos collide with atomic nuclei.

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An announcement by scientists at the Department of Energys Fermilab today significantly clarifies the overall picture of how neutrinos behave.
The results of the so-named MiniBooNE project resolve questions raised by observations an earlier DOE experiment Liquid Scintillator Neutrino Detector (LSND) - in the 1990s that appeared to contradict findings of other neutrino experiments worldwide. The announcement today significantly clarifies the overall picture of how neutrinos behave.
In addition, scientists at Virginia Tech have proposed a new experiment, known as LENS (Low Energy Neutrino Spectroscopy), which will push the search for sterile neutrinos well beyond the scope of the MiniBooNE project.

"The possibility of sterile-neutrino-induced oscillation observed by LSND now seems to be ruled out. But there may still be sterile neutrinos with somewhat different properties" - Jonathan Link, Virginia Tech College of Science physicist who, along with 77 scientists from 16 other universities around the world, was a member of the MiniBooNE collaboration.

Since the LSND result, theorists have used sterile neutrinos to solve many problems in physics from supernova explosions to the mysterious dark matter that binds galaxies together. Virginia Techs LENS (full name here) project will push the search for mysterious sterile neutrinos even further.
Currently, three types or "flavours" of neutrinos are known to exist: electron neutrinos, muon neutrinos and tau neutrinos. In the last 10 years, several experimentsincluding the LSND collaborationhave shown that neutrinos can oscillate from one flavour to another and back. However, reconciling the LSND observations with the oscillation results of other neutrino experiments would have required the presence of a fourth, or "sterile" type of neutrino, with properties different from the three standard neutrinos. The existence of sterile neutrinos would throw serious doubt on the current structure of particle physics, known as the Standard Model of Particles and Forces. Because of the far-reaching consequences of this interpretation, the LSND findings cried out for independent verification.
The MiniBooNE experiment, approved in 1998, took data for the current analysis from 2002 until the end of 2005 using neutrinos produced by the Booster accelerator at the Fermilab. The experiments goal was either to confirm or to refute the startling observations reported by the LSND collaboration, thus answering a long-standing question that has troubled the neutrino physics community for more than a decade.
The MiniBooNE collaboration used a blind-experiment technique to ensure the credibility of their analysis and results. While collecting their neutrino data, the MiniBooNE collaboration did not permit themselves access to data in the region, or "box," where they would expect to see the same signature of oscillations as LSND. When the MiniBooNE collaboration opened the box and "unblinded" its data less than three weeks ago, the telltale oscillation signature was absent.
Simply put, neutrinos are particles that originate from the centre of the sun. They are one of the fundamental particles of the universe but also one of the least understood. Neutrinos differ from electrons in that they do not carry an electric charge and can pass through great distances in matter without being affected by it.
Studying neutrinos helps scientists understand about the sun, stars, and even the deep core of the Earth. It also provides the capability to detect extremely small trace amounts of radioactivity contained in samples of material, resulting in applications for homeland security, microelectronics, and space science.
For its observations, MiniBooNE relied on a 250,000-gallon tank filled with ultra pure mineral oil, clearer than water from a faucet. A layer of 1280 light-sensitive photomultiplier tubes, mounted inside the tank, detects collisions between neutrinos made by the Booster accelerator and carbon nuclei of oil molecules. Since January 2006, the MiniBooNE experiment has been collecting data using beams of antineutrinos instead of neutrinos and expects further results from these new data.

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The initial data from the 10-year long "MiniBooNE" experiment at the Department of Energy's Fermilab significantly clarifies the overall picture of how the neutrino fundamental particles behave.

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Title: Are small neutrino masses unveiling the missing mass problem of the Universe?
Authors: C. Boehm, Y. Farzan, T. Hambye, S. Palomares-Ruiz, S. Pascoli

We present a scenario in which a remarkably simple relation linking dark matter properties and neutrino masses naturally emerges. This framework points towards a low energy theory where the neutrino mass originates from the existence of a light scalar dark matter particle in the MeV mass range. A very surprising aspect of this scenario is that the required MeV dark matter is one of the favoured candidates to explain the mysterious emission of 511 keV photons in the centre of our galaxy. A possible interpretation of these findings is that dark matter is the stepping stone of a theory beyond the standard model instead of being an embarrassing relic whose energy density must be accounted for in any successful model building.

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Since 1983 researchers at the Fermi National Accelerator Laboratory in Batavia, Ill., have plumbed the subatomic realm by smashing high-energy protons and antiprotons together in the Tevatron, the world's most powerful particle collider. Next year, however, the high-energy frontier will move to Europe, where the even more powerful Large Hadron Collider will begin operations near Geneva. Fermilab intends to shut down the Tevatron by 2010. But rather than scrapping the device, lab officials have outlined an ambitious plan to use some of the collider's parts to enhance a promising research program: the study of the mysterious neutrino, whose strange properties may offer clues to new laws of physics.

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