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Clue to Dark Matter Mystery
In article ,
stmx3 wrote: Starblade Darksquall wrote: Their abstract: "We discuss the possibility that the recent detection of 511 keV gamma-rays from the galactic bulge, as observed by INTEGRAL, is a consequence of low mass (~MeV) particle dark matter annihilations. We discuss the type of halo profile favored by the observations as well as the size of the annihilation cross section needed to account for the signal. We find that such a scenario is consistent with the observed dark matter relic density and other constraints from astrophysics and particle physics." What these physicists seem to be implying is that dark matter is simply a field of electrons and/or positrons. They'd better not be implying that - just think about it! You can't have vast quantities of electrons and/or positrons playing the role of dark matter. If you had *just* electrons or just positrons, their electric charge would have hurled them out of the galaxy a long time ago. And if you had *both*, they'd annihilate each other like hell, since there'd be need to be so many - remember, dark matter accounts for more mass than visible matter, and electrons are 1800 times lighter than protons. So, we wouldn't just see some feeble 511 keV glow: we'd see the whole galaxy exploding dramatically! They propose ~1 - 100 MeV darkmatter annihilation as the candidate to produce 511 KeV photons. That makes more sense. But it sounds a little tough to exclude alternate explanations, doesn't it? |
#2
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Clue to Dark Matter Mystery
In article ,
stmx3 wrote: Starblade Darksquall wrote: Their abstract: "We discuss the possibility that the recent detection of 511 keV gamma-rays from the galactic bulge, as observed by INTEGRAL, is a consequence of low mass (~MeV) particle dark matter annihilations. We discuss the type of halo profile favored by the observations as well as the size of the annihilation cross section needed to account for the signal. We find that such a scenario is consistent with the observed dark matter relic density and other constraints from astrophysics and particle physics." What these physicists seem to be implying is that dark matter is simply a field of electrons and/or positrons. They'd better not be implying that - just think about it! You can't have vast quantities of electrons and/or positrons playing the role of dark matter. If you had *just* electrons or just positrons, their electric charge would have hurled them out of the galaxy a long time ago. And if you had *both*, they'd annihilate each other like hell, since there'd be need to be so many - remember, dark matter accounts for more mass than visible matter, and electrons are 1800 times lighter than protons. So, we wouldn't just see some feeble 511 keV glow: we'd see the whole galaxy exploding dramatically! They propose ~1 - 100 MeV darkmatter annihilation as the candidate to produce 511 KeV photons. That makes more sense. But it sounds a little tough to exclude alternate explanations, doesn't it? |
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