Condensed matter effects for high density fusion and the solar neutrino problem

The conventional description of fusion reaction rates needs to be modified in astrophysical environments to account for condensed matter effects. Molecular dynamics simulations show that the elastic particle collision rate In condensed matter environments deviates significantly form the conventional estimate, due to condensed matter reduced volume effects (CMRVE), caused by the hard core-like Coulomb potential at high density. These have analogues in liquids and inside nuclei. CMRVE increases effective number densities leading to an increased fusion rate. In the presence of non-fusing species (such as {sup 4}He for pp fusion), the fusion rate is further increased due to a larger excluded volume for the fusing species. Fitting the central temperature T{sub c} to the observed neutrino fluxes by phenomenological mock-up calculations yields lower T{sub c} by {approximately} 5%, which is a large amount in terms of changes in astrophysical parameters. However, the solar luminosity can be kept constant with a 5% reduction in T{sub c} if CMRVE can be shown to increase the p(p,e{sup +}v{sub e})D fusion rate by 25%. Since CMRVE is expected to affect most solar fusion reactions, it is necessary to redo the SSM calculations with new increased fusion rates including CMRVE. We present new estimates ofmore » fusion rates for p(p,e{sup +} v{sub e})D and {sup 7}Be(p, {gamma}){sup 8}B in the sun which include CMRVE. We also discuss implications of CMRVE for the solar neutrino problem.« less