CCEGA Paper 21: Negative Results and the Silence of CCEGA in the PTA Band

Derives the SGWB amplitude from the CCEGA cosmological bounce at T_QCD = 154 MeV from first principles. Two mechanisms are evaluated: (i) GW production via the dG_eff/dt source term unique to CCEGA, and (ii) radiation from the modulus field phi during the bounce. Both give Omega_GW ~ 10⁻⁸¹–10⁻⁹⁴, many orders of magnitude below NANOGrav sensitivity. The suppression is fundamental: H_bounce/M_Pl ~ 10⁻³⁹ and all semiclassical GW production scales as (H/M_Pl)^2. Known SMBH echoes fall at f > 2000 nHz, outside the PTA band. CCEGA is silent in the PTA band. The frequency prediction f=8.2 nHz of Paper 20 is a robust kinematic result; the coincidence with NANOGrav is numerical, not physical. Negative result documented in the spirit of the programme's methodological commitment.