HOW WELL DO WE (AND WILL WE) KNOW SOLAR-NEUTRINO FLUXES AND OSCILLATION PARAMETERS

Individual neutrino fluxes are not well determined by the four operati ng solar neutrino experiments. Assuming neutrino oscillations occur, t he pp electron neutrino flux is uncertain by a factor of 2, the B-8 fl ux by a factor of 5, and the Be-7 flux by a factor of 45. For matter-e nhanced oscillation (MSW) solutions, the range of allowed differences of squared neutrino masses, Delta m(2), varies between 4x10(-6) eV(2) and 1x10(-4) eV(2), while 4x10(-3)less than or equal to sin(2)2 theta less than or equal to 1.5x10(-2) or 0.5 less than or equal to sin(2)2 theta less than or equal to 0.9. For vacuum oscillations, Delta m(2) v aries between 5x10(-11) eV(2) and 1x10(-10) eV(2), while 0.7 less than or equal to sin(2) theta less than or equal to 1.0. The inferred rang es of neutrino parameters depend only weakly on which standard solar m odel is used. Calculations of the expected results of future solar neu trino experiments (SuperKamiokande, SNO, BOREXINO, ICARUS, HELLAZ, and HERON) are used to illustrate the extent to which these experiments w ill restrict the range of the allowed neutrino mixing parameters. For example, the double ratio (observed ratio divided by standard model ra tio) of neutral current to charged current event rates to be measured in the SNO experiment varies, at 95% confidence limit, over the range 1.0 (no oscillations into active neutrinos), 3.1(-1.3)(+1.8) (small mi xing angle MSW), 4.4(-1.4)(+2.0) (large mixing angle MSW), and 5.2(-2. 9)(+5.6) (vacuum oscillations). We present an improved formulation of the ''luminosity constraint'' and show that at 95% confidence limit, t his constraint establishes the best available limits on the rate of cr eation of pp neutrinos in the solar interior and provides the best upp er limit to the Be-7 neutrino flux. The actual rate of creation of sol ar neutrinos in the solar interior to the rate predicted by the standa rd solar model can vary (while holding the CNO neutrino flux constant) between 0.55 and 1.08 for pp neutrinos and between 0.0 and 6.35 for B e-7 neutrinos.