We review the application of boundary string field theory (BSFT) methods, circa 2001, to the QCD glueball spectrum. The BSFT beta=0 condition, with inputs n=2, χ=3800, t=10⁴ and zero free parameters, yields M₀++/m_ρ = 2. 69. This result matches lattice QCD 2. 58 (14) at 0. 7σ. We further note testable predictions for neutron star maximum mass Mₘax = 2. 18 Mₛun and CMB-S4 observable ΔNₑff = 0. 334.
Mateus de Oliveira Felippe (Mon,) studied this question.