Dark Matter from a Second Warped Throat: Gravitational Freeze‑In in the DBQTM Framework

We extend the Dual-Brane Quantum Tunneling Model (DBQTM) to incorporate dark matter through a multi-throat compactification on a Calabi--Yau manifold.While the first Klebanov--Strassler throat (K₁=203, M₁=17, kd₁ ≈ 375) generates the observed cosmological constant via vacuum energy suppression, a second throat (K₂=39, M₂=35, kd₂ ≈ 35) produces a natural dark matter candidate: the lightest scalar glueball of the confined gauge theory, with mass mDM = k\,e-kd₂ ≈ 133~GeV.Dark matter is produced via UV-dominated gravitational freeze-in through zero-mode graviton exchange, yielding the observed relic abundance ΩDM h² = 0.12 for an inflationary Hubble rate Hᵢnf ~ 10¹³~GeV, which predicts a tensor-to-scalar ratio r ~ 0.001--$0.01$ testable by LiteBIRD and CMB-S4.The dark matter is absolutely stable on cosmological timescales (τ ≈ 1.6 × 10³²~yr) and undetectable via direct detection (σSI ~ 10⁻⁹⁸~cm²).Both the cosmological constant and the dark matter mass are determined by five discrete parameters (K₁, M₁, K₂, M₂, gₛ), with k fixed by the RS geometry and gₛ fixed in the first throat to reproduce the observed ρ_Λ~{DBQTM-Paper1}. The cross-prediction kd₁/kd₂ = K₁ M₂/(K₂ M₁) is verified exactly.The tadpole constraint K₁ M₁ + K₂ M₂ = 4816 requires a Calabi--Yau with Euler characteristic χ ≥ 115,584. 2.0: Adds perturbative brane backreaction analysisconfirming RS consistency (εBR~10⁻³⁴,Appendix~C) and detailed gravitational freeze-in derivation includingwarped lifetime (τ≈2.9×10³³~yr) and decay branchingfractions (Appendix~D). Core predictions unchanged. inflation, Randall--Sundrum, Klebanov--Strassler, Starobinsky, warped extra dimensions, dark matter, string cosmology