2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/81874The proton-proton ($pp$) fusion cross-section found at the heart of solar models is unconstrained experimentally and relies solely on theoretical calculations. Effective field theory provides an opportunity to constrain the $pp$ cross-section experimentally, however, this method is complicated by the appearance of two-nucleon effects in the form of an unknown parameter $L_{1,A}$. We present a method to constrain $L_{1,A}$ using the Standard Solar Model and helioseismology. Using this method, we determine a value of $L_{1,A}$ = 7.0 fm$^{3}$ with a range of 1.6 to 12.4 fm$^{3}$. These results are consistent with theoretical estimates of $L_{1,A} \approx$ 6 fm$^{3}$.14 pages, 3 figures, uses RevTeX 4Nuclear TheoryAstrophysicstext