Can Oscillations Explain Neutrino Anomalies?

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Discussion Overview

The discussion revolves around the phenomenon of neutrino anomalies, specifically the solar and atmospheric neutrino deficits, and the proposed explanation of neutrino oscillations. Participants explore the implications of these anomalies, the validity of experimental results, and the challenges in measuring neutrino properties. The scope includes theoretical considerations, experimental evidence, and ongoing debates within the physics community.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification
  • Experimental/applied

Main Points Raised

  • Some participants describe the solar neutrino deficit as a problem where fewer neutrinos are detected than expected, while others argue that this issue has been resolved by experiments like SNOL.
  • There is a proposal that neutrino oscillation explains the missing neutrinos, with some participants noting the "reappearance" of neutrinos in long-baseline measurements as supporting evidence.
  • Concerns are raised about the possibility that neutrinos could be absorbed or scattered more than previously thought, questioning the reliability of cross-section measurements.
  • Participants discuss various experiments that have measured neutrino cross-sections and the appearance of different neutrino flavors, citing specific experiments like T2K, NOvA, and OPERA.
  • Some participants express skepticism about claims made in videos discussing neutrino anomalies, particularly regarding the interpretation of results from the LSND and MiniBooNE experiments.
  • There is a contention regarding the interpretation of experimental data, with some asserting that MiniBooNE did not confirm LSND and raised concerns about the validity of the anomalies reported.
  • References to recent work and reviews on neutrino cross-sections are shared, indicating ongoing research and interest in the topic.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the interpretation of neutrino anomalies, with multiple competing views remaining on the validity of experimental results and the implications for neutrino physics.

Contextual Notes

Some discussions highlight limitations in the current understanding of neutrino interactions, the dependence on experimental setups, and the unresolved nature of certain anomalies. The debate includes references to historical and contemporary experiments, indicating a complex landscape of findings and interpretations.

  • #31
No, I just tried to keep it simple
 
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  • #32
So, you don't do a calculation but guess at an answer. and when your guess doesn't match reality, it's not that your guess is wrong, it's that neutrino oscillations are a bad theory.

I am unconvinced.
 
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  • #33
Not at all, I am just trying to understand the concept, I did not mean to ruffle your feathers
 
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  • #34
A Majeski said:
I would expect the Solar deficit to be closer to 1/2 or something other than 2/3. This value indicates that the dispersion of three neutrino flavors is basically flat regardless of the detectors proximity to a large neutrino source, like the Sun.
This is wrong. The mechanism at work here is the Mikheev-Smirnov-Wolfenstein effect and adiabatic flavor transitions. The MSW matter effect on oscillations imply that neutrinos exit the Sun almost entirely in the second mass eigenstate (provided that they are energetic enough to be produced above resonance). This in turn means that the nu_e survival probability is based almost exclusively on the nu_e content of that mass eigenstate.

It is also wrong that only two flavors are involved. Theory predicts almost equal numbers of mu and tau neutrinos.

It is not the case that oscillations equilibrate the flavors. The oscillation probabilities depend on several things, including the mixing parameters.

A Majeski said:
also, it seems to me that the neutrino mass change should progress from lightest to heaviest with an accompanied decrease in speed. It should not progress from heaviest to lightest as this would require the speed to increase, I cannot see any example where this occurs in other phenomenon.
This is well known (assuming fixed momentum) and it does not really affect oscillations until wave packets of different mass eigenstates separate which would just average out the oscillations. This does happen for solar neutrinos but as mentioned they effectively only consist of one mass eigenstate anyway so it is not super relevant.

Note: Neutrinos will not change their speed during propagation. They are in a quantum mechanical superposition of their mass states and it is the mass states that move at different velocities.

A Majeski said:
Not at all, I am just trying to understand the concept, I did not mean to ruffle your feathers
You’re not though. You are making assumptions of how things behave and try to draw conclusions based on those (faulty) assumptions. That will never end well and you will not really learn anything. What you should be doing if you wish to understand is to pick up some reference literature on the subject. For example, section III.G of this review.
 
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