LQG dark matter candidate vs rival dark matter candidates

In summary, recent results on dark matter searches have shown no evidence for dark matter candidates, specifically neutralinos, at the LHC. The LUX and panda experiments also found no candidate WIMP events, while axion and ice cube searches for sterile neutrinos have also come up empty. These results have implications for the composition and production of dark matter, ruling out certain mass ranges and theories, but also leaving room for alternative possibilities such as loop quantum black holes. These LQBHs, or self-dual black holes, could potentially be a component of dark matter and emit radiation with energies that could explain observed cosmic rays. However, more research is needed to confirm their existence and role in the universe.
  • #1
kodama
978
132
recent results on dark matter searches

LHC has produced no dark matter candidates, esp neutralinos
LUX/panda has found no candidate WIMP events
axion dark matter searches have come up empty
ice cube sterile neutrinos have come up empty

Ethan Siegel, Contributor
The null detection is incredible, with a fantastic slew of implications:

  1. Dark matter is most likely not made up, 100%, of the most commonly thought-of WIMP candidates.
  2. It is highly unlikely that whatever dark matter is, in light of the LUX results, will be produced at the LHC.
  3. And it is quite likely that dark matter lies outside of the standard mass range, either much lower (as with axions or sterile neutrinos) or much higher (as with WIMPzillas).
http://www.forbes.com/sites/startsw...es-worlds-most-sensitive-search/#732061d35b60

regarding axion dark matter

Search for Spectral Irregularities due to Photon–Axionlike-Particle Oscillations with the Fermi Large Area Telescope
M. Ajello et al. (The Fermi-LAT Collaboration)
Phys. Rev. Lett. 116, 161101 – Published 20 April 2016


Abstract
We report on the search for spectral irregularities induced by oscillations between photons and axionlike-particles (ALPs) in the γ-ray spectrum of NGC 1275, the central galaxy of the Perseus cluster. Using 6 years of Fermi Large Area Telescope data, we find no evidence for ALPs and exclude couplings above 5×10−12GeV−1 for ALP masses 0.5≲ma≲5neV at 95% confidence. The limits are competitive with the sensitivity of planned laboratory experiments, and, together with other bounds, strongly constrain the possibility that ALPs can reduce the γ-ray opacity of the Universe.

  • thumbnail.png
  • thumbnail.png
  • Received 27 November 2015
DOI:http://dx.doi.org/10.1103/PhysRevLett.116.161101

axions have also been tightly consrained. no evidence for axions in mass range that can explain dark matter despite high precision searches.

regarding sterile neutrinos

Searches for Sterile Neutrinos with the IceCube Detector
The IceCube Collaboration
(Submitted on 6 May 2016)
The IceCube neutrino telescope at the South Pole has measured the atmospheric muon neutrino spectrum as a function of zenith angle and energy in the approximate 320 GeV to 20 TeV range, to search for the oscillation signatures of light sterile neutrinos. No evidence for anomalous νμ or ν¯μ disappearance is observed in either of two independently developed analyses, each using one year of atmospheric neutrino data. New exclusion limits are placed on the parameter space of the 3+1 model, in which muon antineutrinos would experience a strong MSW-resonant oscillation. The exclusion limits extend to sin22θ24≤ 0.02 at Δm2∼ 0.3 eV2 at the 90\% confidence level. The allowed region from global analysis of appearance experiments, including LSND and MiniBooNE, is excluded at approximately the 99\% confidence level for the global best fit value of |Ue4|2.
Comments: 9 pages, 5 figures
Subjects: High Energy Physics - Experiment (hep-ex); High Energy Astrophysical Phenomena (astro-ph.HE)
Journal reference: Phys. Rev. Lett. 117, 071801 (2016)
DOI: 10.1103/PhysRevLett.117.071801
Cite as: arXiv:1605.01990 [hep-ex]
(or arXiv:1605.01990v1 [hep-ex] for this version)
Submission history

no evidence for sterile neutrinos.

so a much higher mass range hasn't been ruled out or constrained, but below MACHO and black hole as dark matter.

all standard dark matter are strongly constrained with black hole and macho most strongly constrained.

LQG offers a much higher mass range, produced via gravitational interaction, not weak interaction.

this paper


Gravitational axial perturbations and quasinormal modes of loop quantum black holes

M.B. Cruz, C.A.S. Silva, F.A. Brito
(Submitted on 26 Nov 2015)
Gravitational waves can be used as a way to investigate the structure of spacetime. Loop Quantum Gravity is a theory that propose a way to model the behavior of spacetime in situations where its atomic characteristic arises. Among these situations, the spacetime behavior near the Big Bang or black hole's singularity. A recent prediction of loop quantum gravity is the existence of sub-Planckian black holes called loop quantum black holes (LQBH) or self-dual black holes which correspond to a quantized version of Schwarzschild black hole. In this work, we study the gravitational waves spectrum emitted by a LQBH through the analysis of its the quasinormal modes. From the results obtained, loop quantum black holes have been shown stable under axial gravitational perturbations.
Comments: 9 pages, 4 figures, 2 tables
Subjects: General Relativity and Quantum Cosmology (gr-qc)
Cite as: arXiv:1511.08263 [gr-qc]
(or arXiv:1511.08263v1 [gr-qc] for this version)

Self-dual Black Holes in LQG: Theory and Phenomenology
Leonardo Modesto, Isabeau Prémont-Schwarz
(Submitted on 20 May 2009 (v1), last revised 3 Jun 2009 (this version, v2))
In this paper we have recalled the semiclassical metric obtained from a classical analysis of the loop quantum black hole (LQBH). We show that the regular Reissner-Nordstrom-like metric is self-dual in the sense of T-duality: the form of the metric obtained in Loop quantum Gravity (LQG) is invariant under the exchange "r <-> a0/r" where "a0" is proportional to the minimum area in LQG and "r" is the standard Schwarzschild radial coordinate at asymptotic infinity. Of particular interest, the symmetry imposes that if an observer at "r" close to infinity sees a black hole of mass "m" an observer in the other asymptotic infinity beyond the horizon (at "r" close to "0") sees a dual mass "mp/m" ("mp" is the Planck mass). We then show that small LQBH are stable and could be a component of dark matter. Ultra-light LQBHs created shortly after the Big Bang would now have a mass of approximately "10^(-5) mp" and emit radiation with a typical energy of about 10^(13) - 10^(14) eV but they would also emit cosmic rays of much higher energies, albeit few of them. If these small LQBHs form a majority of the dark matter of the Milky Way's Halo, the production rate of ultra-high-energy-cosmic-rays (UHECR) by these ultra light black holes would be compatible with the observed rate of the Auger detector.
Comments: 18 pages, 32 figures. Extra Plot, Improved Numerical Results and Corrected typos
Subjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
Journal reference: Phys.Rev.D80:064041,2009
DOI: http://arxiv.org/ct?url=http%3A%2F%2Fdx.doi.org%2F10%252E1103%2FPhysRevD%252E80%252E064041&v=3b61e8cb
Cite as: arXiv:0905.3170 [hep-th]
(or arXiv:0905.3170v2 [hep-th] for this version)

Emission spectra of self-dual black holes
Sabine Hossenfelder, Leonardo Modesto, Isabeau Prémont-Schwarz
(Submitted on 2 Feb 2012 (v1), last revised 15 Feb 2012 (this version, v2))
We calculate the particle spectra of evaporating self-dual black holes that are potential dark matter candidates. We first estimate the relevant mass and temperature range and find that the masses are below the Planck mass, and the temperature of the black holes is small compared to their mass. In this limit, we then derive the number-density of the primary emission particles, and, by studying the wave-equation of a scalar field in the background metric of the black hole, show that we can use the low energy approximation for the greybody factors. We finally arrive at the expression for the spectrum of secondary particle emission from a dark matter halo constituted of self-dual black holes.
Comments: 15 pages, 6 figures, typos corrected, reference added
Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
Cite as: arXiv:1202.0412 [gr-qc]
(or arXiv:1202.0412v2 [gr-qc] for this version)

given the mass of

Ultra-light LQBHs created shortly after the Big Bang would now have a mass of approximately "10^(-5) mp" or 10^14 GeV

they must be a promising dark matter candidate not constrained by any observation to date. they are produced via thermal and gravitational interaction, not weak interaction.

perhaps Sabine Hossenfelder aka Bee can enlighten us. there is also a certain parsimony
SM+ LQG with LQG providing the dark matter candidate via gravity. no need for SUSY wimps.

dark matter consisting of Ultra-light LQBHs created shortly after the Big Bang is not constrained by observation and would explain cold dark matter, either a part or all of it.

not sure how this could be detected with Earth bound detectors. but suppose dark matter is indeed Ultra-light QBHs with mass of 10^14 GeV and properties described by the above papers.

would this be evidence self-dual LQG is a strong candidate theory of QG? self-dual LQG theory makes a prediction that could be observed, though the experiments to do so is hard to imagine. it would obviously be much rarer than 100 GEV weak scale neutralino wimps

what are either astronomical or experimental ways to confirm or constrain Ultra-light LQBHs as dark matter?
 
Last edited by a moderator:
  • #3
kodama said:
axions have also been tightly consrained. no evidence for axions in mass range that can explain dark matter despite high precision searches.

No, I don't think that is correct.

https://arxiv.org/abs/1603.06978
http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.161101
"In conjunction with other limits taken at face value [29, 45, 55], the parameter space where ALPs could explain hints for a lower γ-ray opacity compared to EBL-model predictions (light blue region, [25]) is now strongly constrained. The limits do not constrain ALPs that could make up the entire DM content of the Universe."
 
  • Like
Likes kodama
  • #4
atyy said:
No, I don't think that is correct.

https://arxiv.org/abs/1603.06978
http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.161101
"In conjunction with other limits taken at face value [29, 45, 55], the parameter space where ALPs could explain hints for a lower γ-ray opacity compared to EBL-model predictions (light blue region, [25]) is now strongly constrained. The limits do not constrain ALPs that could make up the entire DM content of the Universe."

there are several other experiments attempting to directly detect dm axions with no success thus far.
 

Related to LQG dark matter candidate vs rival dark matter candidates

1. What is LQG dark matter and how is it different from other dark matter candidates?

LQG (Loop Quantum Gravity) dark matter is a proposed candidate for dark matter, which is a type of matter that makes up about 85% of the total matter in the universe. It differs from other dark matter candidates in that it is based on the theory of loop quantum gravity, which suggests that space and time are made up of discrete, quantized units rather than being continuous. This theory also predicts that these quantized units could form a network or lattice-like structure, which could potentially explain the behavior of dark matter.

2. What evidence supports LQG dark matter as a viable candidate for dark matter?

There is currently no direct evidence for LQG dark matter, as it is still a theoretical concept. However, some simulations and observations of the large-scale structure of the universe have shown patterns that are consistent with the predictions of the loop quantum gravity theory. This has led some scientists to believe that LQG dark matter is a promising candidate for further study.

3. How does LQG dark matter compare to other popular dark matter candidates, such as WIMPs and MACHOs?

LQG dark matter differs from other popular candidates in that it is a non-traditional approach based on a different theory (loop quantum gravity) than the more commonly studied WIMPs (Weakly Interacting Massive Particles) and MACHOs (Massive Compact Halo Objects). WIMPs are particles that interact very weakly with regular matter, while MACHOs are massive objects like black holes or brown dwarfs. LQG dark matter does not rely on the existence of new particles or massive objects, but instead proposes a different understanding of space and time.

4. What are some potential drawbacks or challenges to the LQG dark matter theory?

One potential drawback of LQG dark matter is that it is currently a purely theoretical concept and has not yet been observed or detected. In addition, the loop quantum gravity theory is still in its early stages and has not been fully developed or tested. Other challenges include the difficulty of testing the theory and the lack of direct evidence or observational data to support it.

5. What are the next steps for scientists studying LQG dark matter?

The next steps for scientists studying LQG dark matter include further developing the loop quantum gravity theory and conducting simulations and experiments to test its predictions. This could involve studying the large-scale structure of the universe, observing the behavior of galaxies and galaxy clusters, and potentially searching for any signatures or evidence of the proposed lattice structure. Collaboration and interdisciplinary research will also play a crucial role in advancing our understanding of LQG dark matter and its potential as a candidate for dark matter.

Similar threads

  • Beyond the Standard Models
Replies
3
Views
2K
Replies
7
Views
2K
  • Beyond the Standard Models
Replies
9
Views
729
  • Beyond the Standard Models
Replies
1
Views
1K
  • Beyond the Standard Models
8
Replies
264
Views
15K
  • Beyond the Standard Models
Replies
3
Views
8K
  • Beyond the Standard Models
Replies
11
Views
2K
  • Beyond the Standard Models
Replies
4
Views
2K
  • Beyond the Standard Models
Replies
11
Views
2K
  • Beyond the Standard Models
Replies
1
Views
1K
Back
Top