RDCC v42.0 Core Framework + Numerical Fits and Observational Constraints on the Relaxation Parameter α

Relaxation-Driven Cyclic Cosmology (RDCC) v42.0, April 20, 2026 This is the current and recommended version of the RDCC framework. It contains:• the Flagship Paper (submitted to journal)• Companions I–XV (foundational papers)• Companion “Numerical Fits” (new numerical constraints on the single parameter α using χ², MCMC, RSD and Fisher forecast) Note for referees: The submitted manuscript refers to the previous Zenodo record v41.0. All content of v41.0 is fully included in this version v42.0, which additionally provides the new numerical Fits Companion + new Companions XII - XV. Referees are kindly invited to consult the latest version v42.0 for the most up-to-date material. New in v42.0: Companions XII - XV + Companion: Numerical Fits and Observational Constraints on the Relaxation Parameter α in RDCC Fully Integrated RDCC EcosystemRDCC v42.0 includes: RDCC Flagship Paper - Companion I Gravity as the Global Bridge- Companion II Tensor Interference and Log-Periodic Gravitational Waves- Companion III Relaxation Dynamics and the Scalar Sector- Companion IV The Global CPT State and the Mirror Sector- Companion V Observational Synthesis and Global Fit- Companion VI Dynamical Generation of the Relaxation Parameter- Companion VII Boltzmann Hierarchy and Linear Perturbations- Companion VIII Emergent Speed of Light as an Inter-Sector Coherence Boundary- Companion IX Derivation of the Relaxation Rate- Companion X Microscopic Derivation of the RDCC Relaxation Rate from the Dimension-Six Inter-Sector Operator- Companion XI Dark Energy as Emergent Relaxation Dynamics- Companion XII Sectoral Baryon Asymmetry from Opposite Thermodynamic Arrows- Companion XIII The Neutrino Sector in the Relaxation-Driven Cyclic Cosmology Mass Hierarchy, Dirac/Majorana Structure, and Relaxation-Induced Mass Suppression- Companion XIV Primordial Black Holes in the Relaxation-Driven Cyclic Cosmology Relaxation-Suppressed Collapse, Sectoral Asymmetry, and Early-Universe Constraints- Companion XV The Early-Universe Gravitational-Wave Spectrum - Companion: Numerical Fits and Observational Constraints on the Relaxation Parameter α in RDCC - Speculative Extensions - Conceptual Companions II <-- This document is not part of the predictive RDCC framework but a conceptual interpretation! (These analogies do not validate RDCC, but demonstrate that its underlying structure is deeply rooted in known physics.) --- Key puzzles solved by RDCC • The thermodynamic arrow of time: Time and entropy increase are emergent phenomena resulting from the projection of a globally timeless, CPT-symmetric bipartite quantum state onto a single sector. • The cosmological singularity: Replaced by a nonsingular bounce at the CPT fixed point of the global state. • The Tolman low-entropy problem: Global entropy reaches a minimum at the bounce; the apparently low entropy of our sector is a consequence of sectoral projection. • The origin and nature of dark matter: Pure gravitational shadow of the CPT-conjugate mirror sector, interacting only gravitationally. • The apparent weakness of gravity: Effective Newton constant measured by sectoral observers is Geff = GN / (1 + ρ−/ρ+). • Correlated small deviations from ΛCDM: Scalar spectral tilt (n_s − 1 = −2 α_IR), dark radiation excess (ΔN_eff ∼ α_IR), percent-level growth-rate shift in fσ8, and log-periodic modulation in the stochastic gravitational-wave background - all governed by a single parameter α_IR. • The origin of the invariant speed of light c: Emergent inter-sector coherence boundary, the maximum speed at which global quantum coherence can propagate before relaxation enforces decoherence. • The cyclic structure of the Universe: Natural consequence of imposing global CPT symmetry on the full cosmological quantum state. • The late-time cosmic acceleration: Emergent from the same relaxation dynamics that govern early-universe predictions; the freeze-out of the coherence parameter α(a) naturally produces an effective acceleration term without invoking a cosmological constant or new fields. RDCC solves these long-standing puzzles through a single structural postulate - global CPT symmetry of the complete quantum state in a bipartite Hilbert space - together with the minimal dimension-six inter-sector operator. The framework remains highly predictive with only one free parameter. --- Related documents and the development history of the RDCC framework are available on Zenodo:https://zenodo.org/records/18204087 Michael [email protected]