Is this the Dark Matter Particle?

[beecee]

Or is this simply evidence that maybe the standard particle model needs reevaluating? 

 https://www.livescience.com/62721-sterile-neutrino-detected-fermilab.html

A Major Physics Experiment Just Detected a Particle That Shouldn't Exist:

 

Scientists have produced the firmest evidence yet of so-called sterile neutrinos, mysterious particles that pass through matter without interacting with it at all.

The first hints these elusive particles turned up decades ago. But after years of dedicated searches, scientists have been unable to find any other evidence for them, with many experiments contradicting those old results. These new results now leave scientists with two robust experiments that seem to demonstrate the existence of sterile neutrinos, even as other experiments continue to suggest sterile neutrinos don't exist at all.

That means there's something strange happening in the universe that is making humanity's most cutting-edge physics experiments contradict one another.

more at link....

the paper:

https://arxiv.org/pdf/1805.12028.pdf

30 May 2018

The MiniBooNE experiment at Fermilab reports results from an analysis of νe appearance data from 12.84 × 1020 protons on target in neutrino mode, an increase of approximately a factor of two over previously reported results. A νe charged-current quasi-elastic event excess of 381.2 ± 85.2 events (4.5σ) is observed in the energy range 200 < EQE ν < 1250 MeV. Combining these data with the ¯νe appearance data from 11.27 × 1020 protons on target in antineutrino mode, a total νe plus ¯νe charged-current quasi-elastic event excess of 460.5 ± 95.8 events (4.8σ) is observed. If interpreted in a standard two-neutrino oscillation model, νµ → νe, the best oscillation fit to the excess has a probability of 20.1% while the background-only fit has a χ 2 -probability of 5 × 10−7 relative to the best fit. The MiniBooNE data are consistent in energy and magnitude with the excess of events reported by the Liquid Scintillator Neutrino Detector (LSND), and the significance of the combined LSND and MiniBooNE excesses is 6.1σ. All of the major backgrounds are constrained by in-situ event measurements, so non-oscillation explanations would need to invoke new anomalous background processes. Although the data are fit with a standard oscillation model, other models may provide better fits to the data.

Edited June 9, 2018 by beecee

[mathematic]

Unlikely.  There are two issues.  First, some physicists are skeptical about the experiment.  Second, there would be an enormous amount of them to account for the amount of dark matter that has been observed and they would need to move relatively slowly for the current distribution of dark matter.

[T. McGrath]

According to the Standard Model of particle physics neutrinos are supposed to be massless.  If you start giving mass to neutrinos then explaining how neutrinos are able to travel at the speed of light becomes problematic.

[Silvestru]

2 hours ago, T. McGrath said:

According to the Standard Model of particle physics neutrinos are supposed to be massless.  If you start giving mass to neutrinos then explaining how neutrinos are able to travel at the speed of light becomes problematic.

They travel close to the speed of light. The standard model does not predict them to be mass-less anymore.

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Due to their tiny mass, the predicted speed is extremely close to the speed of light in all experiments, and current detectors are not sensitive to the expected difference.

 

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The Standard Model of particle physics assumed that neutrinos are massless. However, the experimentally established phenomenon of neutrino oscillation, which mixes neutrino flavour states with neutrino mass states (analogously to CKM mixing), requires neutrinos to have nonzero masses.

 

[mathematic]

The picture of the standard model is a little misleading.  Lining up the bosons with the fermions hints at relationships which don't exist.

[swansont]

On 6/21/2018 at 3:53 AM, Silvestru said:

They travel close to the speed of light. The standard model does not predict them to be mass-less anymore.

Not sure that's an accurate statement. My understanding was that neutrino oscillations were the first evidence that the electron neutrinos had mass, and neutrino oscillations are not part of the standard model.

[YaDinghus]

4 hours ago, swansont said:

On 6/21/2018 at 9:53 AM, Silvestru said:

They travel close to the speed of light. The standard model does not predict them to be mass-less anymore.

Not sure that's an accurate statement. My understanding was that neutrino oscillations were the first evidence that the electron neutrinos had mass, and neutrino oscillations are not part of the standard model.

I do know that the original prediction was that the neutrinos were massless, and observations to the contrary caused scientists at the time to consider a mechanism that gave them mass. I don't know if you would call the model prior to the massive neutrinos the standard model.

Whatever the case. Something that popsci doesn't mention is that during its oscillations, Neutrinos gain and shed mass (ve are around 2 eV in rest mass while vm and vt are considerably more massive with 1.7 and 15.5 MeV). Sterile neutrinos, if this turns out to be true, should be even more massive, and therefore affected stronger by gravity, and thus keep them closer to other alottments of mass like galaxies.

Also, neutrinos are a 'by-product' of fusion, and since fusion is happening all the time (as long as stars exist) this would imply that the ratio of dark/visible matter is growing, since visible matter is not increasing as far as we know

[swansont]

3 minutes ago, YaDinghus said:

  Something that popsci doesn't mention is that during its oscillations, Neutrinos gain and shed mass (ve are around 2 eV in rest mass while vm and vt are considerably more massive with 1.7 and 15.5 MeV).  

This being QM, it's probably a case of being in a superposition of states, so it's not strictly the case that mass is gained or shed, since the neutrino isn't in any particular state at any given time.

[YaDinghus]

10 minutes ago, swansont said:

This being QM, it's probably a case of being in a superposition of states, so it's not strictly the case that mass is gained or shed, since the neutrino isn't in any particular state at any given time.

So their wave function isn't time symmetric. I don't know what exactly this implies, but I guess it's good to know...

[swansont]

1 minute ago, YaDinghus said:

So their wave function isn't time symmetric. I don't know what exactly this implies, but I guess it's good to know...

I don't know what you mean by this. A superposition of states can be present with a time-independent solution. 

[YaDinghus]

1 hour ago, swansont said:

I don't know what you mean by this. A superposition of states can be present with a time-independent solution. 

I'm not sure it's even relevant here. Neutrinos are weird...

[Silvestru]

7 hours ago, swansont said:

Not sure that's an accurate statement. My understanding was that neutrino oscillations were the first evidence that the electron neutrinos had mass, and neutrino oscillations are not part of the standard model.

 

1 hour ago, YaDinghus said:

I'm not sure it's even relevant here. Neutrinos are weird...

I found a centralized location of neutrino experiments having to do with their mass and oscillation.

http://www.hep.anl.gov/ndk/hypertext/

Maybe it's not part of standard model but:

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massive neutrinos fit in quite nicely with the possibility that the Standard Model is just part of a bigger, better theory

 

[YaDinghus]

3 hours ago, Silvestru said:

 

I found a centralized location of neutrino experiments having to do with their mass and oscillation.

http://www.hep.anl.gov/ndk/hypertext/

Maybe it's not part of standard model but:

 

So, if there are sterile neutrinos, what other sterile matter is there?

[Silvestru]

1 hour ago, YaDinghus said:

So, if there are sterile neutrinos, what other sterile matter is there?

I think the list stops here but I am not joining this hype train. I have been disappointed many times by similar hypothetical "discoveries".

I guess it started from the below paper on arxiv but the results have not been replicated.

https://arxiv.org/pdf/1805.12028.pdf

But I had too much of this subject lately  the only sterile thing I'll have around me the next days is my cat.

[YaDinghus]

2 hours ago, Silvestru said:

But I had too much of this subject lately  the only sterile thing I'll have around me the next days is my cat

I've been seeing it pop up in my feeds for about two weeks now, too. Dark Matter hype is worse thatn WoW xD