Abstract We present the Dual-Brane Quantum Tunneling Model (DBQTM), a geometrically motivated framework for the cosmological constant based on a CPT-symmetric two-brane configuration in a Randall--Sundrum (RS) background with Goldberger--Wise (GW) stabilization. The observed vacuum energy arises from the inter-brane mixing suppression _ = k⁴ (-ngeo kd), with k = 0. 0869\, MPl, ngeo = 0. 720, and kd 375. The 122-order-of-magnitude hierarchy between the natural and observed vacuum energy scales is recast as a moderately large geometric product n kd 270. We derive the Binetruy--Deffayet--Langlois junction conditions self-consistently, showing that the physical brane tension ₑff = VA/2 0. 09\, MPl⁴ exceeds crit by 10^120, making w (z) = -1 + O (10^-119). A no-go theorem establishes that vacuum energy suppression and observable BDL corrections are mutually exclusive within the RS framework. To address the question of why kd 375, we explore four flux-stabilization mechanisms. The most natural is a Klebanov--Strassler embedding, where the brane separation is determined directly by quantized 3-form fluxes: kd = 2 K/ (gₛ M). With gₛ = 1/5, K = 203, M = 17, we obtain kd = 375. 14 and _ within 2\% of the observed value. The cosmological constant becomes a topological invariant --- a consequence of two integers characterizing the flux threading the compactification manifold. 2. 0: Adds parameter scans (Appendix~A), flux vacuum stability via CDL/HM instantons (Appendix~B), andcritical comparison with six competing frameworks includingranked limitations (Section~5). Core physics unchanged.
Riccardo Pilloni (Mon,) studied this question.