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Physicists Set Strongest Limit on Mass of Dark Matter

By Guest PostNovember 30, 2011Science40 gev, alex geringer sameth, anti quark, brown university, cogent, cresst, croton on hudson, dama, dark matter, dark matter particle, dwarf galaxies, expansion of the universe, fermi gamma ray space telescope, fermi lat collaboration, galaxies, gamma ray, giga electron volts, gravitational effects, jet of particles, libra, limit, mass of dark matter, milky way galaxy, mysterious particle, NASA, nobel prize, physics, planets, quark, savvas koushiappas, signal to noise ratio, stars, theories, universe, weakly interacting massive particle, wimp

*Brown University physicists have set the strongest limit for the mass of dark matter, the mysterious particles believed to make up nearly a quarter of the universe. The researchers report in Physical Review Letters that dark matter must have a mass greater than 40 giga-electron volts. The distinction is important because it casts doubt on recent results from underground experiments that have reported detecting dark matter.*

PROVIDENCE, R.I. [Brown University] — If dark matter exists in the universe, scientists now have set the strongest limit to date on its mass.

In a paper to be published on Dec. 1 in Physical Review Letters (available in pdf), Brown University assistant professor Savvas Koushiappas and graduate student Alex Geringer-Sameth report that dark matter must have a mass greater than 40 giga-electron volts in dark-matter collisions involving heavy quarks. (The masses of elementary particles are regularly expressed in term of electron volts.) Using publicly available data collected from an instrument on NASA’s Fermi Gamma-ray Space Telescope and a novel statistical approach, the Brown pair constrained the mass of dark matter particles by calculating the rate at which the particles are thought to cancel each other out in galaxies that orbit the Milky Way galaxy. (more…)

Berkeley Lab’s Saul Perlmutter wins Nobel Prize in Physics

By Guest PostOctober 4, 2011Science2011 nobel prize in physics, accelerating expansion of the universe, adam riess, anisotropy of the cosmic microwave background radiation, astrophysicist, berkeley lab, brian schmidt, Chile, dark energy, department of energy, expansion of the universe, france, george smoot iii, gravity, high z supernova search team, international supernova cosmology project, Japan, knowledge, lawrence berkeley national laboratory, mysterious force, nature of dark energy, nobel prize, nobel prize in physics, paul alivisatos, saul perlmutter, spain, supernova cosmology project, supernovae, Sweden, swedish kroner, united kingdom, united states, university of california at berkeley

BERKELEY, CA — Saul Perlmutter, an astrophysicist at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory and a professor of physics at the University of California at Berkeley, has won the 2011 Nobel Prize in Physics “for the discovery of the accelerating expansion of the universe through observations of distant supernovae.” Perlmutter heads the international Supernova Cosmology Project, which pioneered the methods used to discover the accelerating expansion of the universe, and he has been a leader in studies to determine the nature of dark energy.

Perlmutter shares the prize with Brian Schmidt and Adam Riess, leader of the High-z Supernova Search Team and first author of that team’s analysis, respectively, which led to their almost simultaneous announcement of accelerating expansion. (more…)

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Physicists Set Strongest Limit on Mass of Dark Matter

Berkeley Lab’s Saul Perlmutter wins Nobel Prize in Physics