Are there any particles with all the properties of a WIMP

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Discussion Overview

The discussion centers on the existence of particles within the Standard Model of Particle Physics that possess all the properties of Weakly Interacting Massive Particles (WIMPs). Participants explore various candidates for dark matter, including neutrinos and other theoretical particles, while examining the definitions and implications of the WIMP concept.

Discussion Character

  • Debate/contested
  • Exploratory
  • Technical explanation

Main Points Raised

  • Some participants assert that there are no particles within the Standard Model that qualify as WIMPs, while extensions to the model propose various WIMP candidates that remain undiscovered.
  • Neutrinos are discussed as having properties similar to WIMPs, but concerns are raised about their mass and the implications for large-scale structure in the universe if they were the sole component of dark matter.
  • There is a distinction made between the typical definition of WIMPs, which refers to particles with significant mass (around 100 GeV), and the looser usage of the term that includes any weakly interacting dark matter candidates.
  • Participants mention keV sterile neutrinos as potential dark matter candidates, but caution against equating WIMPs directly with dark matter due to the existence of other possibilities like axion-like particles and WIMPzillas.
  • Discussion includes the evolution of the WIMP concept and the challenges associated with lighter dark matter candidates, which have observational issues.
  • Some participants reference past research on MeV sterile neutrinos and question the current status of the parameter space for these candidates.
  • Supersymmetry is proposed as a potential explanation for dark matter, suggesting that supersymmetric neutrinos could qualify as WIMPs if they possess sufficient mass.
  • Warm dark matter, including neutrinos, is noted as not entirely excluded from the WIMP definition, highlighting uncertainty regarding the mass of dark matter constituents.

Areas of Agreement / Disagreement

Participants express differing views on the classification of neutrinos as WIMPs and the implications of their properties for dark matter theories. There is no consensus on the existence of WIMPs within the Standard Model or the suitability of various dark matter candidates.

Contextual Notes

Participants highlight limitations in the definitions and assumptions surrounding WIMPs and dark matter candidates, as well as the unresolved status of certain theoretical models and parameter spaces.

Quds Akbar
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Are there any particles on the Standard Model of Particle Physics with all the properties of a WIMP particle(Weakly Interacting Massive Particles)?
 
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Not within the standard model of particle physics. In several extension, there are different WIMP candidates, but none have been discovered so far.
 
Neutrinos have the properties of WIMPs. However, if DM were composed entirely of neutrinos we would see different large scale structure than we do.
 
Vanadium 50 said:
Neutrinos have the properties of WIMPs. However, if DM were composed entirely of neutrinos we would see different large scale structure than we do.

I've always thought of the "massive" in WIMPs to mean that they have large mass, and not just that they have some mass. I think most WIMP candidates are in the 100GeV range? Neutrinos are totally not...not even close by any stretch of the imagination, to this mass scale.
 
Matterwave said:
I've always thought of the "massive" in WIMPs to mean that they have large mass, and not just that they have some mass. I think most WIMP candidates are in the 100GeV range? Neutrinos are totally not...not even close by any stretch of the imagination, to this mass scale.
You are correct. The WIMP concept typically refers to a weakly interacting particle with a mass large enough for the WIMP miracle to occur, i.e., produced by thermal freeze out when it is non-relativistic. Neutrinos certainly do not fit this description. However, the term WIMP is sometimes used more loosely to refer to any dark matter candidate which interacts weakly - but again, this is not the typical definition of a WIMP.
 
The idea of a WIMP has evolved from when it was first proposed, based on observations and theoretical ideas. One idea is that "weak" means "Weak" - i.e. it is THE weak nuclear force, and not just a weak force. Another is "massive" - the reason people talk about masses in the 100's of GeVs today is because lighter alternatives have problems with observation. Non-discovery being a big one.

I think my answer is still right - neutrinos could be dark matter candidates. They aren't, but they could be. That is, they have the right particle properties, but the wrong cosmology.
 
keV sterile neutrinos are still dark matter candidates. However, putting an equal sign between WIMPs and dark matter is dangerous as there are still many other possibilities (axion-like particles, keV sterile neutrinos, WIMPzillas, asymmetric dark matter, SIMPs, FIMPs, just to mention a few). Of course, neutrinos were dark matter candidates, but I would not have considered them a WIMP candidate. I also believe this is still the most common usage of the WIMP terminology.
 
I've read a few papers a while back published ~a decade ago that were discussing the potential for MeV sterile neutrino dark matter candidates (which I thought were "WIMPs" but apparently were not). That paper did not rule out much of the parameter space (150MeV-500MeV and sin^2(theta)<10^-4 I think) at that time. Has the rest of the parameter space been roughly ruled out in the decade since?
 
Some people hope that dark matter will be explained by "supersymmetry," whereby each particle in the standard model has a supersymmetric pair particle that we generally do not see. The lightest such particle would likely be some type of supersymmetric neutrino, so it would be like a neutrino, but it would need to be much more massive, so would still qualify as a WIMP.
 
  • #10
Warm dark matter, as in neutrinos, is not yet entirely excluded and meets the WIMP definition. One of the problems with dark matter is we really don't have a clue about how massive the constituent particles need to be to match what little we know about dark matter. I still suspect we will eventually conclude there is a model for dark matter that is similarly diverse to that of the 'standard' model.
 

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