Capacity Selection of Left-Handed Weak Interactions: A QTT Derivation of Neutrino Chirality, V−A Parity Violation, and the Active-Neutrino Mass Spectrum from First Principles

The Standard Model accommodates parity violation in the weak interaction by hand: only the left-handed components of fermions are placed in SU(2)_L doublets while right-handed components are gauge singlets. This article gives a structural origin for that asymmetry inside Quantum Traction Theory (QTT). The key result is a Capacity-Selected Bundle-Visibility principle that combines a budget statement with a localisation statement. Budget: a parity-doubled fundamental dyad would require two independent 2π closures at one address, costing 4π, in violation of A7's per-address bundle budget. Localisation: the A5 visible/hidden factorisation makes this budget statement intrinsically local, closing the loophole that L…