Proton-proton fusion in effective field theory to fifth order

The proton-proton fusion process pp --> de(+)v(e) is calculated at threshold to fifth order in pionless effective field theory. There are two unknown two-body currents contributing at the second and fourth orders. Combined with the previous results for v(e)d and (v) over bar (e)d scattering, computed to third order in the same approach, we conclude that a similar to 10% measurement of reactor ed scattering measurement could constrain the pp --> de(+) v(e) rate to similar to7% while a similar to3% measurement of v(e)d --> e(-)pp could constrain the pp rate to similar to 2%. (C) 2001 Published by Elsevier Science B.V.