V.R307 — The neutrino exponent

The neutrino mass exponent 15 in m_nu ~ m_e iota_tau^15 decomposes as 15 = 7 + 2 x 4: the bulk exponent 7 (from Epstein zeta at s=4) plus two spectral gap factors (from fiber breathing modes). This is not a fitted exponent but a structural consequence of the same spectral analysis producing R = iota_tau^(-7). Awaits direct measurement by KATRIN or Project 8.