Nuclear fusion reactions

The p-p nuclear fusion reactions

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Most Important Nuclear Physics Experiment

The most important nuclear physics experiment to perform in connection with solar neutrino research is an accurate remeasurement of the proton capture rate on 7Be. The flux of the higher energy neutrinos (from 8B beta-decay) that is measured in the Kamiokande, Super-Kamiokande, and SNO solar neutrino experiments is proportional to the low energy value for the proton capture cross section. According to the combined standard model (standard solar model and standard electroweak theory), the rate measured in the chlorine solar neutrino experiment is also proportional to this cross section. The rate at which 8B is produced in the sun is so slow that the value of the proton capture cross section on 7Be that is assumed in the solar model calculations has no perceptible effect on the solar models. This is the reason for the linear dependence of the 8B neutrino flux on the 8B production cross section. If you want to cite a reference for this viewgraph, (in order to help support your proposal or for whatever reason), see pg. 482 of ``Solar Neutrinos: Where We Are, Where We Are Going,'' ApJ 467, 475 (1996), hep-ph/9512285.

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7Be Flux Independent of 8B Uncertainties

The flux of 7Be solar neutrinos is relatively accurately determined by standard solar models, but-if one assumes nothing happens to solar neutrinos after they are created-the7Be neutrinos appear to be almost entirely absent in the gallium and chlorine solar neutrino experiments. This is one of the most severe aspects of the ``solar neutrino problem.'' This viewgraph shows that the flux of 7Be solar neutrinos is independent of the rate at which 8B neutrinos are produced by the relatively less certain cross section for proton capture on 7Be. The reason is that the proton capture, which gives rise to 8B neutrinos, is very much slower than the electron capture that gives rise to 7Be neutrinos. The argument that supports this viewgraph is given in detail in the text following and preceding equation (6) of ApJ 467, 475 (1996).

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