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1answer
49 views

Dark matter and supersymmetric particles

Is there a possibility to consider supersymmetric particles of fermions and bosons as the unknown dark matter?
0
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1answer
47 views

Are pressureless, collisionless and self-interacting dark matter all synonymous?

Is there any distinction between pressureless, collisionless and self-interacting dark matter or does being one imply the other?
1
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1answer
58 views

Which decoupled first? The dark matter or the CMB photons?

According theories that work best for the structure formation which happened first in the history of the evolution of the Universe, the decoupling of dark matter or the decoupling of photons? How sure ...
1
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2answers
86 views

Doesn't dark matter imply a new force?

Given that every particle that we have experimental confirmation of is an oscillation of its field (from what we know), and given dark matter is thought to be a particle yet undiscovered according to ...
0
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1answer
42 views

Dark Matter gamma-ray flux from hadronic annihilation channels?

For a project I am currently reading into indirect detection of Dark Matter via gamma-rays from DM subhalo's. I understand that there is a possibility of DM annihilating with each other in these ...
2
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1answer
65 views

Dark matter relative velocity

In Dark Matter Indirect Detection literature, it is usually said that the relative velocity of dark matter particles in the galactic halo is about $$ v \sim 10^{-3}c$$ See for an example this lecture ...
2
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1answer
25 views

How can I understand the reaction rate of WIMP dark matter intuitively?

I'm reading a cosmology textbook(sorry it's Japanese) and stacked at statement that If the mass of WIMP is enough smaller than 100GeV, the reaction rate is represented as $\langle \sigma_a |\mathbf{\...
2
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1answer
171 views

Light neutrino number from the invisible decay width of $Z$ boson, and precluding heavy neutrinos as dark matter candidate

The $Z$ boson decays into pairs of quarks and leptons. While the decays to quarks pairs and charged lepton pairs can be observed, the decays to $\nu\bar\nu$ are cannot be. By subtracting the visible ...
3
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1answer
69 views

What formula is used to make exclusion plot in the direct detection of dark matter?

The idea of direct detection of dark matter is that a dark matter particle striking some underground target will cause the target nucleus to recoil. From the recoil, one can determine the scattering ...
2
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1answer
87 views

Is it possible to break supersymmetry in such way that the SUSY partners of the known particles have a much lower mass as opposed to greater?

To continue, is it possible to break SUSY in a way that leaves some of the SUSY partners about equal in mass? These issues arose in connection with an unpublished ab initio calculation of the ...
2
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1answer
54 views

Is it sufficient to consider the uncharged dark matter and a $\mathbb{Z}_2$ symmetry to prevent its decay into photons?

Higgs boson, though electrically neutral, can decay to produce a pair of photons i.e., have electromagnetic interactions. See the answer here. Therefore, it appears that making dark matter ...
-2
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1answer
51 views

Can black holes effect light or just what the light reflects off of [closed]

Can light be shifted or stopped by anything other than a solid? I ask because when observing black holes you can see light funneling into the sphere. My thought was that if what’s being pulled into ...
31
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1answer
5k views

Why is Anti-helium so important in the search for dark matter?

I've been reading/hearing that if the AMS satellite measures a significant flux of anti-helium in cosmic rays, that would be an irrefutable proof of dark matter. I was wondering: Why is that? what is ...
1
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0answers
104 views

What if Dark Matter is Majorana Fermion?

Few reasons to believe Dark Matter is Majorana fermion: https://arxiv.org/abs/1711.03877: second contra argument by Jordan and Pauli. "A non vanishing zero-point energy of elementary fields should ...
4
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1answer
142 views

How are the dark matter (DM) thermalization rates derived in singlet DM model?

This well-cited paper talks about a minimal renormalizable extension to the Standard Model (SM) to incorporate particle dark matter (DM) into it by adding a real scalar field $S$ which (unlike the ...
2
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2answers
439 views

Why do we think that the dark sector is simpler?

Matter makes up roughly $5\%$ of the Universe while dark matter makes up roughly $25\%$. For matter and radiation, we have a complicated Standard model with many generations of fermions and various ...
0
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1answer
60 views

How could we detect a dark matter particle?

If dark matter only interacts via gravity, how is detection of a dark matter particle proposed? Don't current particle detectors rely on the other (non-gravitational) interactions?
0
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1answer
312 views

Can Dark Matter be…(massive) gravitons?

The dark matter particle has NOT been found. Despite the quantity of models, I wonder if dark matter could be some (exotic) type of (interacting) gravitons. Is that possible?
4
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1answer
114 views

About the consequences of $\mathbb{Z}_2$ invariance in dark matter models

This well-cited paper talks about is a minimal renormalizable extension to the Standard Model (SM) to incorporate particle dark matter (DM) into it by adding a real scalar field $S$ which (unlike the ...
5
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1answer
386 views

Why is the Standard model Higgs not a candidate of dark matter (in particular, a WIMP)?

Please consider me as a naive self-learner in this field. The Standard Model (SM) Higgs boson is electrically neutral and has a mass of around $125$ GeV (which lies in the WIMP window i.e., between ...
4
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2answers
108 views

What are the steps to identify a dark matter candidate?

By looking at the Lagrangian of a simple particle physics model, how do people identify the dark matter (DM) candidates, if any? One of the criteria is to check whether the electric charge of the ...
1
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1answer
85 views

Are weakly interacting massive particles interacting weakly?

When talking about Weakly Interacting Massive Particles (WIMPs) as Dark Matter candidates, do we mean that they interact via the weak force (possibly communicating with the SM by exchange of $W^\pm$ ...
-3
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1answer
62 views

Could Dark Matter be found by building a Hadron Collider that is the size of the earth?

I believe that through the current Collider created by CERN is finding out new data on a small scale. What if Dark matter could be found by an even bigger Collider like one that could be built around ...
14
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1answer
1k views

Is matter - dark matter symmetry possible?

The gravitational lensing evidence suggests massive and relatively dense accumulations of dark matter in space. However, dark matter collapsing to dense regions is unlikely due to energy conservation. ...
1
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2answers
154 views

Why should dark matter be stable (i.e., non-decaying)?

People say that the dark matter has to be stable and electrically neutral. Since there is no particle in the Standard Model which is both stable (non-decaying) and electrically neutral it cannot ...
3
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1answer
345 views

What is the vacuum alignment problem?

Can someone explain with a simple example what is meant by vacuum alignment in a field theory? Recently I have heard this term in a seminar and when I asked the speaker I got an unsatisfactory answer: ...
1
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2answers
137 views

Can the centers of galaxies act as particle accelerators?

At the centers of galaxies, the amount of dark matter is much higher than that of ordinary matter. So the centers can effectively gravitationally attract and accelerate ordinary matter- without much ...
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0answers
90 views

How to calculate annihilation cross section, given effective operator for Datk Matter?

Suppose I have an effective operator of the form $\frac{1}{\Lambda^{2}}$$\bar{\chi}\chi\bar{q}q$, where $\chi$ is an fermionic DM and 'q' is the quark. Given this operator, How do I calculate the DM ...
6
votes
2answers
413 views

How bad would it break physics if dark matter was not “particles”?

Some people suggest that dark matter might not even be particles at all —that’s just what physisists expect to find with reference to what they are familiar with. But, I learned, from layman books of ...
1
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1answer
483 views

Dark matter annihilation cross section

What is the meaning of upper limit of annihilation cross section? Sometimes I have seen that $\langle\sigma v\rangle = 3.0 \times 10^{-26}\,{\rm cm}^{3}\,{\rm s}^{-1}$ or $2.0 \times 10^{-25}\,{\rm cm}...
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1answer
400 views

What happens when antimatter hits dark matter?

What happens when antimatter hits dark matter? If its better for the thought experiment, lets say they collide with equal velocity. One particle for both would be enough, but an answer regarding ...
4
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3answers
741 views

Most likely candidate for dark matter?

I have read into some depth about the various candidates for dark matter, the merits and flaws of each. However what I have been unable to attain from texts alone is what is the most likely ...
5
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2answers
233 views

Could a 4th generation neutrino be a viable candidate for dark matter?

Dark matter does not interact with electromagnetic radiation. Neutrinos also don't interact via electromagnetism, which would make neutrinos a good candidate for dark matter. However because of the ...
0
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1answer
343 views

What type of dark matter candidate does the Madala particle predict if any? [closed]

The Madala particle has been theorized as the boson that may give dark matter its mass. I have read a few articles in the press on this new hypothetical particle but must admit I am a little confused....
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0answers
107 views

How do trace element abundances show that dark matter exists in both baryonic and non - baryonic forms?

I can't seem to find an answer to this question anywhere, any help would be greatly appreciated. Thanks in advance.
9
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2answers
451 views

Is it possible that all “spontaneous nuclear decay” is actually “slow neutrino” induced?

This thought was inspired by a comment from the current leading answer, by @Sentry, to the question Where are all the slow neutrinos? This [slow-neutrino induced nuclear decay] will still be an ...
1
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1answer
126 views

How do funnels hinder (help?) detection of dark matter?

I came across some a new (to me) bit of terminology at a seminar recently. In the context of dark matter scattering off of atomic nuclei (but I think it may apply more generally for any particle ...
1
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2answers
3k views

Higgs boson and dark matter.

In the standard model the Higgs boson gives the mass to other particles, but in the Universe we know that the 80% of mass is in form of dark matter, that is not constituted by known particles. The ...
0
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0answers
45 views

Does matter shrink due to energy radiation and does it have anything to do with dark matter and dark energy?

Is matter shrinking? Is shrinking the cause of concentrated dark matter that makes up matter moving from concentration to unconcentration. Does dark energy and expansion of the universe come from this ...
0
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2answers
417 views

WIMP dark matter annihilation rate equation (approximation)?

WIMP is a possible dark matter candidates, which self-annihilates. What is the WIMP annihilation rate, as a function of density? Most sources state this scales as $\rho^2$, (density squared), but ...
2
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2answers
394 views

Why standard model particles cannot be dark matter particles

I'm interested if any of the particles in the standard model could be potential candidates for dark matter? I know that we do not see dark matter, therefore dark matter does not interact ...
3
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1answer
136 views

Where would dark matter be produced?

There are a zoo of dark matter candidates. Are there any candidates which could be produced in extreme conditions such as black holes/active galactic nuclei/pulsars? After reading an article on WIMPs ...
0
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0answers
177 views

Implications of dark matter imprints on Cosmic Microwave Background Radiation?

Looking at this link, CMB Anisotropy, I have two questions regarding the possible creation and properties of dark matter: If dark matter has left it's imprint on the CMB, that to me, would imply ...
5
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1answer
147 views

Where would the dark matter particle fit inside a picture of the standard model of particle physics?

Where would the dark matter particle fit inside a picture of the standard model of particle physics? While I am particularly fond of the Sterile Neutrino, I have not been able to find any example of ...
0
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1answer
48 views

is electromagnetic phenomena and particle behavior dependent on dark matter?

Dark matter permeates space and coalesce s in its own gravitational attraction. It neither absorbs or emits light or interacts well with baryonic matter. It deflects light on a path and is the sub ...
0
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1answer
207 views

Methods of detecting gravitino DM and possible implications for theories of everything

Let me summarize my thoughts about topics in theoretical physics: Theory of everything: The theory of everything aims to unite all the four forces of nature into one single elegant equation. ...
1
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1answer
333 views

Do most physicists believe that axions exist? [closed]

Is the theoretical justification behind proposing axions sufficiently robust, like, say the Higgs boson prior to its detection, that one should consider the existence of axions as generally accepted (...
3
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0answers
68 views

Active-sterile mixing for KeVins

People sometimes talk about KeV mass sterile neutrinos as a warm dark matter candidate. I think they call them KeVins (horrible name btw). Now, In order for it to be a good dark matter candidate it ...
6
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2answers
191 views

Which cosmological dark matter theory is most compatible with current particle physics?

This occurred to me while I was writing Why hasn't warm dark matter replaced cold dark matter as the standard model of cosmology? but I think this deserves a question of its own. The background ...
11
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1answer
693 views

Justification for new theories of Particle Physics and General Relativity

In reference to arxiv:1212.4893v3 and arxiv:1206.5078v2 papers of Ma and Wang, they have proposed new theories in particle physics, the weakton model where quarks and leptons are formed using these ...