NASA AMS-2 Particle Detector on ISS Finds Dark matter in Cosmic Rays - Update

The Alpha Magnetic Spectrometer attached to the International Space Station.

Credit: NASA

New research published Thursday in the journal Physical Review Letters shows researchers are making important progress in the hunt for dark matter, using the Alpha Magnetic Spectrometer (AMS), a state-of-the-art cosmic ray particle physics detector located on the exterior of the International Space Station.

The results include new detections of anti-matter particles that could provide new clues in the search for dark matter, invisible matter that can't be directly detected but can be inferred. An overview of the latest findings can be found here.

Computer-generated drawing of the Alpha 
Magnetic Spectrometer (AMS). Credit: NASA

The MIT group leads an international collaboration of scientists that analyzed two and a half years' worth of data taken by the Alpha Magnetic Spectrometer (AMS), a large particle detector mounted on the exterior of the International Space Station, that captures incoming cosmic rays from all over the galaxy.

Among 41 billion cosmic ray events, instances of cosmic particles entering the detector, the researchers identified 10 million electrons and positrons, stable antiparticles of electrons.

Positrons can exist in relatively small numbers within the cosmic ray flux.

An excess of these particles has been observed by previous experiments, suggesting that they may not originate from cosmic rays, but come instead from a new source.

In 2013, the AMS collaboration, for the first time, accurately measured the onset of this excess.

The new AMS results may ultimately help scientists narrow in on the origin and features of dark matter, whose collisions may give rise to positrons.

"The AMS results announced today are tremendously provocative, and will drive scientists around the world to continue pursuing one of the biggest mysteries in the cosmos: dark matter," NASA chief scientist Ellen Stofan said at the agency’s headquarters in Washington.

"The clear and definitive data from AMS represent the caliber of scientific discovery enabled by our unique laboratory in space, the International Space Station."

"Today we are one step closer to answering the fundamental questions about how our universe works, and we look forward to many more exciting twists in this developing story."

AMS was constructed, tested and operated by an international team of 56 institutes from 16 countries and organized under the sponsorship of the U.S. Department of Energy's Office of Science.

NASA's Johnson Space Center in Houston manages the AMS Integration Project Office. AMS was launched on space shuttle Endeavour on May 16, 2011.

Operations on the space station began three days later. AMS continues operations aboard the station today.

More Information
"Electron and Positron Fluxes in Primary Cosmic Rays Measured with the Alpha Magnetic Spectrometer on the International Space Station" Phys. Rev. Lett. 113, 121102 – Published 18 September 2014 - 10.1103/PhysRevLett.113.121102