Searches for the characteristic large-angle B-mode polarization signature of primordial gravitational waves (BICEP2/Keck, Planck) have yielded only upper limits on the tensor-to-scalar ratio: r < 0.03 to 0.04 at 95% confidence. The earlier 2014 BICEP2 detection turned out to be polarized dust foregrounds (BICEP2/Keck 2015; Planck XI 2016). Many theoretically attractive single-field inflation models are now disfavored, forcing fine-tuned inflationary potentials to keep r below the bound.
The standard model with single-field slow-roll inflation requires a primordial gravitational-wave background of measurable amplitude. The model has no natural mechanism to make r vanishingly small without invoking baroque inflationary potentials. Continued non-detection therefore tightens the inflationary parameter space toward implausible values.
SCT replaces the hot-dense-center with a superluminal collision and the thermalized debris field that became our visible universe. From this single change, no inflationary epoch ever occurred in our cosmological history. The cascade infrastructure (P22, P36, P37, P38, terminating before t ≈ 1 second per P40) solves the horizon problem (recid 14), the flatness problem (recid 10), and the structure-seeding problem without inflation. Primordial gravitational waves at the level inflation would produce simply do not exist in our patch, because the inflationary mechanism that would source them never operated.
SCT predicts a tensor-to-scalar ratio r < 10⁻⁵, far below the BICEP/Keck upper bound of r < 0.06 and far below the design sensitivity of CMB-S4 (~10⁻³ by 2030). The continued absence of B-mode detection across two decades of intensive searching is exactly what M1 predicts; each null result strengthens the case for the no-inflation cascade cosmology relative to the inflationary alternative. There is no need to fine-tune inflationary potentials to suppress r below the experimental bound, because no inflationary potential is invoked.
The same M1 mechanism that dissolves the horizon, flatness, hierarchy, and monopole problems predicts the absence of primordial B-modes. All five tensions trace back to one structural change: replacing the hot-dense-center singular origin with the superluminal-collision cascade. The collision cascade thermalizes the overlap volume simultaneously without needing inflation to bring distant regions into prior causal contact, and the same cascade leaves no inflationary tensor-mode signature.
Detection of primordial B-modes at tensor-to-scalar ratio r > 0.005 (LiteBIRD, CMB-S4) at greater than 5σ would refute the no-inflation cascade cosmology and re-introduce the inflationary picture. This is the cleanest near-term falsifier of M1: a single confirmed primordial B-mode detection would refute SCT's claim that no inflationary epoch occurred.