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Solar Neutrino problem

  1. Sep 5, 2007 #1
    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!

    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...:grumpy:
    it should be "J.N. Abdurash_itov" without "_"..
  2. jcsd
  3. Sep 5, 2007 #2
    Might it have someting 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.
  4. Sep 5, 2007 #3
    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.
  5. Sep 5, 2007 #4
    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.
  6. Sep 5, 2007 #5


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    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 )
  7. Sep 5, 2007 #6
    I have thought that before but not quite sure. It is true that oscillation angles do depend on energy.

    um..i dont think so as those experiments only measured the electron neutrinos but no other flavors.
  8. Sep 5, 2007 #7


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