Could dark matter have gamma-ray absorption lines?

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Discussion Overview

The discussion centers around the potential for dark matter to absorb gamma radiation, specifically exploring the concept through a model involving magnetic monopoles. Participants consider the feasibility of gamma-ray absorption spectroscopy in sky surveys and the implications of their calculations regarding dark matter properties.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant inquires about the existence of sky surveys capable of performing gamma-ray absorption spectroscopy and speculates on the absorption of gamma radiation by dark matter.
  • Another participant presents a calculation based on a dark matter model involving a bound state of magnetic monopoles, estimating a Rydberg energy of about a MeV, assuming monopole masses of 1 TeV.
  • A later reply retracts the initial calculation, suggesting a mistake with the fine structure constant and referencing GUT theories that propose monopole masses could be significantly higher than 10^{16} GeV.
  • One participant expresses skepticism about the viability of magnetic monopoles as dark matter, arguing that they would interact too strongly with each other and with normal matter.
  • Concerns are raised about the challenges of conducting gamma-ray spectroscopy in astronomy due to low number counts, with a general expectation that gamma rays from dark matter annihilation would be observed rather than absorption.

Areas of Agreement / Disagreement

Participants express differing views on the viability of magnetic monopoles as dark matter. While some explore the theoretical implications of their calculations, others challenge the assumptions and suggest that magnetic monopoles may not be suitable candidates for dark matter.

Contextual Notes

Participants note limitations in their calculations, including potential errors in the fine structure constant and assumptions regarding monopole masses. The discussion reflects uncertainty regarding the interaction properties of magnetic monopoles and their implications for dark matter models.

johne1618
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Are there sky surveys that perform gamma-ray absorption spectroscopy?

I was wondering if dark matter might absorb gamma radiation.

I have done a simple Bohr-atom type calculation assuming a dark matter model of a bound state of a North and South magnetic monopole and found a Rydberg energy of about a MeV. I assume that the mass of the monopoles is 1 Tev; masses less than this limit have apparently been excluded by particle accelerator experiments (to a confidence of 95%). I also assume that the monopoles have the minimum magnetic charge.
 
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johne1618 said:
I have done a simple Bohr-atom type calculation assuming a dark matter model of a bound state of a North and South magnetic monopole and found a Rydberg energy of about a MeV. I assume that the mass of the monopoles is 1 Tev; masses less than this limit have apparently been excluded by particle accelerator experiments (to a confidence of 95%). I also assume that the monopoles have the minimum magnetic charge.

Actually I retract this calculation - I think I got my fine structure constant upside-down! And also GUT theories think the mass of the monopole is probably bigger than [itex]10^{16}[/itex] GeV!
 
johne1618 said:
Are there sky surveys that perform gamma-ray absorption spectroscopy?

I was wondering if dark matter might absorb gamma radiation.

I have done a simple Bohr-atom type calculation assuming a dark matter model of a bound state of a North and South magnetic monopole and found a Rydberg energy of about a MeV. I assume that the mass of the monopoles is 1 Tev; masses less than this limit have apparently been excluded by particle accelerator experiments (to a confidence of 95%). I also assume that the monopoles have the minimum magnetic charge.
It's somewhat difficult to do spectroscopy in general with gamma rays, as least where astronomy is concerned. The number counts are just too low. But I think the general expectation is that we'd see gamma rays from dark matter annihilation, but that the dark matter won't do much if any absorption.

That said, I don't think that magnetic monopoles can work as dark matter. They'd interact far too strongly with one another and normal matter.
 
johne1618 said:
Actually I retract this calculation - I think I got my fine structure constant upside-down! And also GUT theories think the mass of the monopole is probably bigger than [itex]10^{16}[/itex] GeV!
Quite possibly!
 

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