Solving the Solar Neutrino Problem

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Discussion Overview

The discussion revolves around the solar neutrino problem, specifically addressing the discrepancies in observed solar neutrino fluxes from different experiments, namely those using Cl-37 and Ga-71. Participants explore potential reasons for the variations in results, focusing on the detection of different neutrino flavors and the implications of neutrino oscillation.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant notes that the observed flux ratio from the Cl-37 experiment was about 0.29, while the Ga-71 experiments reported ratios of 0.55-0.60, questioning the reasons for this discrepancy.
  • Some participants propose that the differences might relate to the three flavors of neutrinos, suggesting that different experiments may detect different states of neutrinos.
  • Another participant mentions that all experiments were observing electron neutrinos, implying that flavor changes may not account for the discrepancies.
  • One argument suggests that the GALLEX results could be explained by a capture rate for low energy neutrinos being closer to theoretical predictions, which may involve energy-dependent flavor fluctuations.
  • Some participants express uncertainty about the consistency of the experimental results, with one suggesting that when considering experimental errors, the results might still be consistent.
  • There is a mention of a later experiment that measured muon neutrinos, although some participants challenge the idea that the earlier experiments measured anything other than electron neutrinos.

Areas of Agreement / Disagreement

Participants express differing views on the reasons behind the observed discrepancies in neutrino fluxes, with no consensus reached on a singular explanation. The discussion remains unresolved regarding the implications of neutrino flavors and the consistency of the experimental results.

Contextual Notes

Participants acknowledge the potential influence of experimental errors and the complexity of neutrino oscillation, but do not resolve these issues. The discussion reflects a range of hypotheses without definitive conclusions.

tnho
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In the solar neutrino experiments, there were deficits in the observed solar neutrino flux when compared with the theoretical values. If i just focus on the Cl-37 and Ga-71 reactions to detect solar neutrinos, there is a question confuses me a lot.
That is,

from the result of experiment done by Davis (using Cl-37), the ratio of the observed flux to the expected flux was about 0.29. However, from the result of SAGE and GALLEX (using Ga-71) at later time, the ratio were about 0.55-0.60, which were much different from the previous case. Does anyone know the reason behind??

Thank you very much!

Reference:
J.N.Abdura****ov et al., in Results from SAGE (The Russian American Gallium Experiment), Phys. Lett. B328 (1994) 223-248

P.S. the name cannot be displayed...
it should be "J.N. Abdurash_itov" without "_"..
 
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Might it have something to do with Neurtinos coming in three flavours?

As I understand it the current theory is that neutrinos change between three states, it may be that one of the expriments detects only one state of nuetrino whereas the second experiment (using different detectors) might be able to detect two types.
 
max_emerso said:
Might it have something to do with Neurtinos coming in three flavours?

As I understand it the current theory is that neutrinos change between three states, it may be that one of the expriments detects only one state of nuetrino whereas the second experiment (using different detectors) might be able to detect two types.

You are right. Neutrinos DO change their flavors (or states).
However, all experiments mentioned above were all observing the electron neutrinos with the same length traveled.
 
One argument I heard to explain the GALLEX results was that the capture rate for low energy neutrinos was closer to the theoretical result. This hinged on a energy dependent flavor fluctuation.

But, I think if you take into account the all the experimental error, the two experiments are consistent with each other. This is only from memory, so I may be wrong.
 
tnho said:
In the solar neutrino experiments, there were deficits in the observed solar neutrino flux when compared with the theoretical values. If i just focus on the Cl-37 and Ga-71 reactions to detect solar neutrinos, there is a question confuses me a lot.
That is,

from the result of experiment done by Davis (using Cl-37), the ratio of the observed flux to the expected flux was about 0.29. However, from the result of SAGE and GALLEX (using Ga-71) at later time, the ratio were about 0.55-0.60, which were much different from the previous case. Does anyone know the reason behind??

Thank you very much!

Reference:
J.N.Abdura****ov et al., in Results from SAGE (The Russian American Gallium Experiment), Phys. Lett. B328 (1994) 223-248

P.S. the name cannot be displayed...
it should be "J.N. Abdurash_itov" without "_"..

The reason for they got higher observed flux was that they now could measure muon neutrinos as well (if I remember right, did a course in neutrino astrophysics last semster and have a lot of pdf's if you want )
 
Norman said:
One argument I heard to explain the GALLEX results was that the capture rate for low energy neutrinos was closer to the theoretical result. This hinged on a energy dependent flavor fluctuation.

But, I think if you take into account the all the experimental error, the two experiments are consistent with each other. This is only from memory, so I may be wrong.

I have thought that before but not quite sure. It is true that oscillation angles do depend on energy.


malawi_glenn said:
The reason for they got higher observed flux was that they now could measure muon neutrinos as well (if I remember right, did a course in neutrino astrophysics last semster and have a lot of pdf's if you want )

um..i don't think so as those experiments only measured the electron neutrinos but no other flavors.
 
tnho said:
I have thought that before but not quite sure. It is true that oscillation angles do depend on energy.




um..i don't think so as those experiments only measured the electron neutrinos but no other flavors.


Then I must have rememberd wrong, altough there was one experiment later that also measured the flux of muon neutrinos