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 ams report by cern article
Geneva 3 April 2013. The international team running the Alpha Magnetic Spectrometer (AMS1) today announced the first results in its search for dark matter. The results, presented by AMS spokesperson Professor Samuel Ting in a seminar at CERN2, are to be published in the journal Physical Review Letters. They report the observation of an excess of positrons in the cosmic ray flux.
URL: http://press.web.cern.ch/press-relea...xcess-space
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sciamr
The new LUX results also cast doubt on previous claims of possible dark matter detection. The DAMA (for DArk MAtter) project in Italy claimed to have seen signs of WIMPs more than a decade ago, and more recently the CDMS (Cryogenic Dark Matter Search) and the CoGeNT (Coherent Germanium Neutrino Technology) experiment, both in Minnesota, saw handfuls of events that might be attributable to dark matter. “I’m afraid I can’t see their claims really surviving this,” Gaitskell says.
The other teams, however, are not ready to concede defeat. Juan Collar of the University of Chicago, who heads the CoGeNT project, says he believes that the LUX team has not properly accounted for electric field effects and may therefore have overestimated the sensitivity of the xenon detector for low-mass WIMPs. Blas Cabrera of Stanford University, who leads the CDMS project, also maintains that what his project has seen may still prove to be dark matter. “It is unlikely that LUX has ruled out the entire region of interest” for low-mass WIMPs because xenon is not as sensitive as other materials to dark matter in that mass range, he says. (CDMS uses silicon and germanium detectors.)
URL: http://www.scientificamerican.com/ar...null-result
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why-particle-physics-matters
Particle physics has revolutionized the way we look at the universe. Along the way, it’s made significant impacts on other fields of science, improved daily life for people around the world and trained a new generation of scientists and computing professionals.
URL: http://www.symmetrymagazine.org/arti...ics-matters
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ntrs dm
The explanation for the survival of some matter may lie in subatomic particles called neutrinos. These particles might have a special property that would give rise to neutrino-less double beta decay.
When an atom undergoes one type of beta decay, a neutron inside its nucleus spontaneously transforms into a proton, electron and antineutrino (the antimatter counterpart of the neutrino); in a type of inverse beta decay, the neutron absorbs a neutrino and morphs into a proton and electron.
Image of neutrino flavors
Kamioka Observatory/ICRR/University of Tokyo
Neutrinos oscillate between three flavors: electron, muon and tau, each with a combination of three unique masses. If neutrinos are Majorana particles, then each of the flavors is its own antiparticle.
In neutrino-less double beta decay, both processes would happen in tandem: The antineutrino produced by the first type of decay would serve as the neutrino that enters into the second. Such a dual reaction can occur only if neutrinos and antineutrinos are one and the same particle, as the Italian physicist Ettore Majorana hypothesized in 1937. Because neutrinos are electrically neutral, nothing forbids them from being “Majorana particles,” or both matter and antimatter at once.
“It seems natural that the neutrino is its own antiparticle,” said Bernhard Schwingenheuer, a physicist at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. “And in this case, neutrino-less double beta decay should exist.”
If the decay does exist, proving neutrinos are Majorana particles, this could explain the matter-antimatter asymmetry.
URL: https://www.simonsfoundation.org/qua...-asymmetry/
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