Solar neutrino energy spectrum.

Numerical values for energy spectra for different solar neutrino sources are available at this url.


Standard neutrino spectrum from ^8B decay
Author(s): John N. Bahcall, E. Lisi, D. E. Alburger, L. De Braeckeleer, S. J. Freedman, and J. Napolitano
Journal: Physical Review C, 54, 411-422 (July 1, 1996); nucl-th/9601044.

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Abstract:This paper presents a systematic evaluation of the shape of the neutrino energy spectrum produced by beta-decay of 8B. The range of uncertainties are determined from laboratory data and from forbidden and radiative corrections. A best-fit numerical spectrum is given, as well as two extreme deviations from the standard spectrum that represent spectra that are different by effectively ± 3 standard deviations. Slightly improved 8B neutrino absorption cross sections are computed for the chlorine and the gallium solar neutrino experiments.

The Superkamiokande and SNO solar neutrino experiments will measure the shape of the 8B neutrino spectrum above about 5 MeV. An observed distortion of the 8B solar neutrino energy spectrum outside the range given in the present work could be considered as evidence, at an effective significance level of greater than three standard deviations, for physics beyond the standard electroweak model.

Central Temperature of the Sun Can be Measured via the 7Be Solar neutrino Line
Author(s): John N. Bahcall
Journal: Physical Review Letters, 71, 2369-2371 (October 11, 1993) hep-ph/9309292.

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Abstract: A precise test of the theory of stellar evolution can be performed by measuring the difference in average energy between the neutrino line produced by 7Be electron capture in the solar interior and the corresponding neutrino line produced in a terrestrial laboratory. The high temperatures in the center of the sun broaden the line asymmetrically, FWHM = 1.6 keV, and cause an average energy shift of 1.3 keV. The width of the 7Be neutrino line should be taken into account in calculations of vacuum neutrino oscillations.

Shapes of solar neutrino spectra: unconventional tests of the standard electroweak model
Author(s): John N. Bahcall
Journal: Physical Review D, 44, 1644-1651 (September 15, 1991).

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Abstract:The shapes of the neutrino energy spectra produced by beta-decays or by nuclear reactions in the solar interior are compared to the corresponding spectral shapes that are produced in a terrestrial laboratory. The most important effects of the sun, caused by thermal motion of the neutrino emitting nuclei and by gravitational redshifts, are shown to be small. Any currently measurable difference between the observed shape of a solar neutrino energy spectrum and the spectrum shape for a terrestrial neutrino source must be due to a departure from the standard electroweak model.

Line Versus Continuum Solar Neutrinos
Author(s): John N. Bahcall
Journal: Phys. Rev. D, 41, 2964 (15 May 1990)

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Abstract: The rate of neutrino line emission is calculated for nuclei that are usually assumed to produce only continuum neutrino emission. A convenient formula is derived that gives for solar interior conditions the ratio of the rates of neutrino line emission to continuum neutrino emission. The only significant line emission from the solar interior is expected from the pep and 7Be-electron capture reactions.

Do hep neutrinos affect the solar neutrino energy spectrum ?
Author(s): John N. Bahcall, Plamen I. Krastev
Journal:Physics Letters B, 436/3-4, 243-250 (September 24, 1998), hep-ph/9807525

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Abstract:If the low energy cross section for 3He + p--> 4He + e+ + nue, the `hep' reaction, is  >~  20 times larger than the best (but uncertain) theoretical estimates, then this reaction could significantly influence the electron energy spectrum produced by solar neutrino interactions and measured in the SuperKamiokande, SNO, and ICARUS experiments. We compare predicted energy spectra for different assumed hep fluxes and different neutrino oscillation scenarios with the observed SuperKamiokande spectrum. The spectra with enhanced hep contributions provide better fits to the SuperKamiokande data.

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