Far out cosmology: dark matter signals (Introduction)

by David Turell , Thursday, May 07, 2015, 01:47 (3275 days ago) @ David Turell

Possible ways to see or find particles that represent dark matter and create gamma rays:-http://www.scientificamerican.com/article/galactic-signal-boosts-lhc-s-dark-matter-search/?WT.mc_id=SA_WR_20150506-"In 2009, Hooper and Lisa Goodenough, then a graduate student at New York University, were the first to spot the signal, in data from NASA's Fermi Gamma-Ray Space Telescope. They proposed that the bump was a signature of dark matter. Two colliding dark-matter particles would annihilate each other, just as ordinary matter does with antimatter. The annihilation would generate a succession of short-lived particles that would eventually produce ?-rays.-"But the proposed particle, which has been dubbed the hooperon or gooperon after its proponents, soon ran into problems with physicists' favourite version of supersymmetry. Although the minimal supersymmetric standard model (MSSM) allows for dark-matter particles with the estimated mass of hooperons—about 25-30 gigaelectronvolts (1 GeV is roughly the mass of a proton)—multiple experiments had suggested that the particles must be heavier. To accommodate hooperons, MSSM would have to be modified to an extent that makes many physicists uncomfortable. “It would have required a completely new theory,” says Sascha Caron, a particle physicist at Radboud University Nijmegen in the Netherlands, who leads the team behind the latest calculations.-*****-"Armed with this insight, Caron and his collaborators recalculated the predictions of the MSSM theory and found another potential explanation for the excess—an existing dark-matter candidate called a neutralino. The neutralino was heavy enough not to be excluded by previous experiments, yet light enough to potentially be produced in the second run of the LHC.-"Caron's model also produces a prediction for the amount of dark matter that should have been created in the Big Bang that is compatible with state-of-the-art observations of the cosmic microwave background—the relic radiation of the Big Bang—performed by the European Space Agency's Planck probe (see Nature http://doi.org/38k; 2014). This cannot be a coincidence, he says. “I find this quite amazing.'”-They might be on to something. The LHC has a chance of finding a piece of the puzzle.