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Dark matter candidates, what chances would you give them?

by EL
Tags: candidates, chances, dark, matter
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EL
#73
Mar14-06, 03:42 AM
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Quote Quote by turbo-1
From what I have read (and I will qualify this by saying that I have a physical revulsion to tacking over a hundred new dimensionless parameters on the standard model to extend it with MSSM, so I have not been a real fan of any brand of SUSY) LSPs (in pairs) can decay in pairs into lighter baryonic particles plus gamma rays.
When two particles interact and annihilate into something new, we usually don't call it a "decay". "Decay" is something a single particle does. That's why I objected to your use of the word. But anyway...
Given the predicted flux of LSPs, shouldn't we have observed at least one such decay by now? If not, why not? Indirect detections of LSP seem a whole lot more likely than direct detections.
I'll repeat:
Quote Quote by EL
Think of this: Interactions between WIMPs and ordinary matter in the direct detection experiments are not frequent enough to be detected. The density of ordinary matter in a detector is way higher than the expected local WIMP density. Which event should occur more often: WIMPs interacting with the detector, or WIMPs interacting with WIMPs?What conclusion can be drawn?
turbo
#74
Mar14-06, 01:10 PM
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Thanks for the clarification on the use of decay products vs aniihilation products. Do you know of a paper that lays out an estimate for the WIMP annihilation rate (perhaps as a percentage of total flux)? I have not been able to find one.
SpaceTiger
#75
Mar14-06, 01:57 PM
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Quote Quote by turbo-1
Thanks for the clarification on the use of decay products vs aniihilation products. Do you know of a paper that lays out an estimate for the WIMP annihilation rate (perhaps as a percentage of total flux)? I have not been able to find one.
Here's an estimate based on an excess of microwave emission near the center of the galaxy:

Finkbeiner 2004
turbo
#76
Mar15-06, 10:54 AM
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Thank you for the link, ST. I have done a little searching to determine detector volumes and found the dimensions of a "drift chamber" that is 26cm radius with a 16cm radis core through which the beam runs, and a chamber length of 2m. The detector has a radial cross section of about 1318cm2 and a total volume of 263,600 cm3.

Assuming a flux of 6x104 WIMPs /s/cm2 (from the paper I linked previously) and a longitudinal detector cross/section of 5200cm2, there should be 3.12x108 WIMPS traversing the detector every second. Shouldn't we have seen at least one WIMP annihilation event in all the years particle accelerators/colliders have been in operation?
Chronos
#77
Mar16-06, 01:31 AM
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I assume you have some statistics in mind.


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