- #1
kodama
- 1,072
- 144
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:
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.
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?
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:
- Dark matter is most likely not made up, 100%, of the most commonly thought-of WIMP candidates.
- It is highly unlikely that whatever dark matter is, in light of the LUX results, will be produced at the LHC.
- 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).
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.
- Received 27 November 2015
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:
