sterile neutrinos nearly ruled out

[Lawrence Crowell]

https://phys.org/news/2021-10-scientists-hint-sterile-neutrino.html?fbclid=IwAR3QesvJ874rclgYU2IxPaMPc8bu87NZhXQjT7_WL4LdZ3fsplZZXinLn70

[John Clark]

Lawrence, any guesses as to what Dark  Matter could be?  Nobody can find any evidence of WIMPS and now sterile neutrinos seems to have bit the dust. Would you bet your money on Axions, or some modification of General Relativity (teleparallel gravity perhaps) or none of the above?

John K Clark

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On Thu, Oct 28, 2021 at 6:57 PM Lawrence Crowell <goldenfield...@gmail.com> wrote:

https://phys.org/news/2021-10-scientists-hint-sterile-neutrino.html?fbclid=IwAR3QesvJ874rclgYU2IxPaMPc8bu87NZhXQjT7_WL4LdZ3fsplZZXinLn70

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[Lawrence Crowell]

On Thursday, October 28, 2021 at 9:08:55 PM UTC-5 johnk...@gmail.com wrote:

Lawrence, any guesses as to what Dark  Matter could be?  Nobody can find any evidence of WIMPS and now sterile neutrinos seems to have bit the dust. Would you bet your money on Axions, or some modification of General Relativity (teleparallel gravity perhaps) or none of the above?

John K Clark

==========

I have no commitment to any particular theory. Dark matter might turn out to be some new physics involving mass-energy in an entirely different form from what we traditionally know as particles or fields. Dark energy is most likely some sort of vacuum energy, where the big unknown is how the vacuum energy is so small compared to what QFT predicts. Dark matter is not homogeneous and isotropic as is dark energy that is presumed to give the de Sitter-like expansion curvature. Yet it is still possible that dark energy is some vacuum type of physics. I have pondered that the large energy excess we expect for dark energy might in fact be some localized form of vacuum energy that condensed in the early universe, and this excess remains as DM. 

The phenomenologies proposed so far seem to be falling apart. WIMPs are mostly likely ruled out. Sterile neutrinos appear to be gone. Axions remain a possibility, though so far attempts to detect them have come up null. As a result the most honest thing that can be said is we really have no certainty about the nature of DM.

LC

[Jesse Mazer]

When you say "WIMPs are most likely ruled out" is that related to failure to find supersymmetric particles at LHC? (Correct me if I'm wrong, but my understanding was that many physicists hoped supersymmetry would solve the 'naturalness problem' of the weak energy scale in a way that required supersymmetric particles to have masses in that range, but advocates of the landscape model like Susskind thought there needn't be any 'explanation' for the energy scales of different forces beyond the anthropic principle.) Or are there other reasons to rule them out, like cosmological simulations based on WIMPs being unable to match certain cosmological observations about the real universe?

Jesse

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[Brent Meeker]

On 10/29/2021 4:15 AM, Lawrence Crowell wrote:

On Thursday, October 28, 2021 at 9:08:55 PM UTC-5 johnk...@gmail.com wrote:

Lawrence, any guesses as to what Dark  Matter could be?  Nobody can find any evidence of WIMPS and now sterile neutrinos seems to have bit the dust. Would you bet your money on Axions, or some modification of General Relativity (teleparallel gravity perhaps) or none of the above?

John K Clark

==========

I have no commitment to any particular theory. Dark matter might turn out to be some new physics involving mass-energy in an entirely different form from what we traditionally know as particles or fields. Dark energy is most likely some sort of vacuum energy, where the big unknown is how the vacuum energy is so small compared to what QFT predicts.

I liked Vic's idea that the holographic principle suggests that the QFT prediction is just overcounting the degrees of  freedom. 

Brent

[Lawrence Crowell]

The whole low energy SUSY theory appears to be in trouble. The breaking of SUSY as the TeV scale appears not to work. This eliminates the neutralino, which is a condensate of supersymmetric partners of the Z particle and photon, appears to not exist. This does remove to a fair degree a SUSY predicted WIMP particle, the neutralino. 

LC

[Lawrence Crowell]

 I have worked out how in the collision of black holes there can be gravitons in the Bondi news or gravitational radiation produced. These gravitons are induced by quantum hair on the event horizon, and in the moments (10^{-20} sec or so)  this quantum hair generates quantum information that can escape out to I^+ ( or I^∞). The main point of this paper was to present a possible empirical test for quantum gravitation. This quantum hair is defined by the correlation of states on either side of the event horizon. This means on a deeper level QFT amplitudes are not freely specified on spatial surfaces and that quantum fields are more fundamentally topological rather than determined with gauge redundancies.

This is a nonlocality to quantum gravitation that liberates us from the Wightman conditions on QFT amplitudes on spatial surfaces. Gravitation has a type of nonlocality, where p_μ = T_{μν}e^ν is a momentum and we might want to evaluate this with a Gauss-law ∮ p_μ dx^μ = ∫∫∇_ν p^μ dx^ν∧dx^μ. The covariant derivative will act on the basis vector e_ν in the definition of the 4-momentum and this will generate a connection term. This is a nonlocalization of momentum-energy in general relativity. Momentum-energy is generally specified only in a very local region that is nearly flat. In the case of Petrov type D solutions for black holes energy can be specified globally with an ADM mass. In general spacetimes though these conservation laws occur only when there is a Killing vector that defines a Noether theorem on symmetry and conserved quantity.

Quantum gravitation is then because of this nonlocalizability such that local operators or amplitudes cannot be as freely specified. Across an event horizon amplitudes on either side are complementary to each other, and this fixes any gauge freedom between them. These fields and the resulting Hilbert space cannot be partitioned across the horizon; this is a topological condition on the occurrence of fields. 

LC

[Jesse Mazer]

But even if low energy SUSY is ruled out, isn't it possible that supersymmetric particles would exist but at much higher energies than the LHC can reach, and if so couldn't such particles still fill the role of WIMPs in dark matter theories? That's what I was saying about the landscape model in string theory, I thought that at least some advocates of the landscape believed in supersymmetry but saw no particular reason to believe it would be a low-energy version that would solve the hierarchy problem. For example, when I was looking for info on this I found this quote from p. 259 of the book Naturalness, String Landscape and Multiverse:

"We should emphasise, however, that low-scale SUSY is certainly not a prediction of string theory. 10d stringy SUSY may be broken directly in the compactification process (e.g. through a non- Calabi–Yau compactification) or at any energy scale between KK-scale and weak scale."

To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/e126d7f2-a194-4a6b-80f7-757e38088b00n%40googlegroups.com.

[Lawrence Crowell]

On Sunday, October 31, 2021 at 1:34:45 PM UTC-5 jessem wrote:

But even if low energy SUSY is ruled out, isn't it possible that supersymmetric particles would exist but at much higher energies than the LHC can reach, and if so couldn't such particles still fill the role of WIMPs in dark matter theories? That's what I was saying about the landscape model in string theory, I thought that at least some advocates of the landscape believed in supersymmetry but saw no particular reason to believe it would be a low-energy version that would solve the hierarchy problem. For example, when I was looking for info on this I found this quote from p. 259 of the book Naturalness, String Landscape and Multiverse:

"We should emphasise, however, that low-scale SUSY is certainly not a prediction of string theory. 10d stringy SUSY may be broken directly in the compactification process (e.g. through a non- Calabi–Yau compactification) or at any energy scale between KK-scale and weak scale."

That is entirely my thesis. Supersymmetry is a quantum gravitational physics.

LC