Operator-Level Proton-Decay Exposure of the QDL–SO10–1 Benchmark: Dimension-Six Operators, Wilson Coefficients, Hadronic Inputs, and Channel-Level Lifetimes

The QDL–SO10–1 grand-unification sequence defines a closure-first SO(10)-compatible benchmark within the Quantized Dimensional Ledger (QDL) program. Papers #1–#3 established the initial benchmark trilogy: a fixed SO(10)-compatible benchmark, its low-energy phenomenology, and a stress-test / robustness audit. Paper #5 began the executable hardening sequence by revising the gauge-closure target to inverse alpha_U = 44.501718, corresponding to alpha_U = 0.022471, and by rescaling the benchmark proton-decay exposure. Paper #6 supplied a reduced block-level scalar-threshold derivation of the calibrated high-scale offsets, advancing the benchmark from calibrated executable gauge closure to block-level scalar-derived gauge closure. This paper supplies the v0.4 proton-decay hardening layer. Its purpose is to replace the previous scaling-level proton-decay exposure estimate with a benchmark-level operator calculation. The calculation constructs a dimension-six baryon-number-violating operator basis, assigns Wilson coefficients at the unification scale, evolves them to the hadronic scale using a declared renormalization factor, applies benchmark hadronic matrix inputs, and computes channel-level partial widths and lifetimes. The channel flavor factors used here are benchmark exposure factors, not fitted CKM, PMNS, or Yukawa predictions. The hadronic formula is a declared benchmark normalization for reproducible exposure accounting, not a full lattice-QCD plus chiral-effective-field-theory treatment. Using M_XY = 1.00 x 10^16 GeV, g_U squared = 0.282379, and g_U = 0.531393, the base gauge-mediated Wilson scale is C_0(M_U) = 2.823789 x 10^-33 GeV^-2. With benchmark running factor A_R = 2.5, pion matrix element W_pi = 0.012 GeV^3, kaon matrix element W_K = 0.010 GeV^3, and declared channel flavor-exposure factors, the benchmark central lifetimes are: tau(p to e+ pi0) = 2.162772 x 10^36 yr, tau(p to mu+ pi0) = 8.651086 x 10^36 yr, tau(p to anti-nu K+) = 1.453338 x 10^38 yr, tau(p to anti-nu pi+) = 8.676449 x 10^36 yr, and tau(p to e+ K0) = 3.310443 x 10^38 yr. The benchmark survives v0.4 operator-level proton-decay exposure: all benchmark central channel lifetimes are above present experimental limits, with the cleanest gauge-mediated benchmark channel remaining p to e+ pi0. This result does not complete the QDL–SO10–1 flavor program. The next paper, Paper #8 / v0.5, replaces benchmark exposure factors with flavor and leptogenesis feedback. The v0.4 standard is not proton-decay avoidance; it is operator-level exposure with explicit survival and failure channels.