Number 295 (Story #1), November 13, 1996 by Phillip F. Schewe and Ben Stein CAN HELIUM-3 HELP THE SOLAR NEUTRINO PROBLEM? The shortfall in the measured solar neutrino flux, especially arising from Be-7 and B-8 decays, may require a particle physics fix (the shortfall can be accounted for if neutrinos oscillate from one type to another) or a modification in the standard solar model. Wick Haxton of the University of Washington (haxton@emmy.phys.washington.edu) and Andrew Cumming of UC Berkeley, although interested in the neutrino oscillation solution, have in a new paper sought to re-examine the solar model, particularly the role of helium-3. He-3 is both produced (in fusion reactions such as p+p-->d followed by d+p-->He-3) and consumed throughout the sun's core. Over the long life of the sun the He-3 abundance will be much higher in the cooler, outer reaches of the core than at the center. Haxton and Cumming pose this speculative question: what if some of the He-3 sinks (much as convective plumes do in Earth's mantle) toward the center of the solar core where, producing an out-of-equilibrium concentration of He-3 which would favor He-3+He-3 reactions at the expense of He-3 +He-4 reactions; the latter contribute to the production of Be-7 and B-8, which in turn spawn exactly the high-energy neutrinos which are found lacking in earthly detectors. This He-3 transport scheme, if valid (both for the sun and for other stars), would nudge the expected neutrino fluxes much closer to the observed values. The cycling of He-3 would also manifest itself in other observable ways, such as in helioseismology and in the way red giant stars blow off He-3 into space. (Physical Review Letters, 25 November.)