Light Quark Mass Ratios and Pion Properties from Geometric Yukawa Couplings in G2 Compactification

The light quark mass ratio m_u/m_d and the pion mass have been derived from the Yukawa coupling structure of M-theory compactified on a seven-dimensional manifold of G2 holonomy. The first-generation Yukawa couplings, determined by the electromagnetic fine-structure constant and the geometric moduli of the Joyce orbifold, have yielded the scale-independent predictions m_u/m_d = 1/2 and (m_d - m_u)/(m_d + m_u) = 1/3, in agreement with the FLAG 2024 lattice averages at 0.8 sigma and 1.3 sigma, respectively. The pion mass has been obtained through the Gell-Mann-Oakes-Renner relation at next-to-leading order in chiral perturbation theory with lattice-determined non-perturbative parameters, giving m_pi = 140.8 +/- 5.3 MeV in 0.9% agreement with the experimental value 139.570 MeV. The geometric determination of the quark mass ratio has reduced the number of independent low-energy constants in the O(p^4) SU(3) chiral Lagrangian from approximately twelve to approximately seven, representing a 40% parameter reduction. All predictions have employed the same three geometric constants (K_0, C_LIG, C_QG) previously used to derive twenty-two observables across the gauge, lepton, neutrino, cosmological, and nuclear sectors with a mean deviation of 2.0%. The prediction m_u/m_d = 1/2 constitutes a sharp, falsifiable target for future sub-percent lattice QCD determinations.