Theoretical Foundations of Oscillating Brane Dark Matter - Part 2

4. Comparative Analysis

4.1 Model Comparison Table

Criterion Oscillating Brane ΛCDM MOND
DM Nature Geometric effect from extra dimensions Unknown particles (WIMPs, axions) No DM, modified gravity
Theoretical Basis String theory/M-theory (RS extension) Particle physics extensions Empirical modification
Free Parameters 3 (τ₀, f_osc, L) 2+ (Ω_c, σ_v, m_χ) 1 (a₀) + relativistic ext.
CMB Fit Quality ΔC_ℓ/C_ℓ < 10⁻³ χ²/dof ≈ 1.00 Poor without 2eV neutrinos
Galaxy Rotations v⁴ ∝ M_b automatically Requires NFW/Einasto profiles v⁴ ∝ M_b by design
Tully-Fisher σ ~0.05 dex predicted ~0.3 dex (with scatter) ~0.05 dex (built-in)
Cluster M/L ratio 300-400 (factor 5-6 boost) 200-500 (varies) Fails without DM
Bullet Separation 150 kpc naturally Explained (collisionless) Unexplained
Cusp-Core Cores ~10 kpc Cusps (ρ ∝ r⁻¹) Cores (by construction)
Missing Satellites Factor 2-3 reduction Too many by 5-10× Better match
Direct Detection σ < 10⁻⁴⁸ cm² forever σ > 10⁻⁴⁷ cm² expected No prediction
S₈ Tension Resolved (-5.2%) 3σ tension Not addressed
H₀ Tension Potential resolution 5σ tension Not addressed
GW Prediction f₀ = 1.6×10⁻¹⁷ Hz None specific None
Falsifiability Multiple clear tests Particle discovery Limited tests

4.2 Advantages Over Competitors

vs ΛCDM:

  • Explains DM-baryon coupling naturally
  • No need for undiscovered particles
  • Potentially resolves small-scale issues
  • Provides unified framework (DM + DE from branes)

vs MOND:

  • Works at all scales (galaxies to cosmology)
  • No need for complicated relativistic extensions
  • Explains cluster dynamics and lensing
  • Compatible with CMB observations

5. Testable Predictions and Falsifiability

5.1 Numerical Predictions Table

Observable Prediction Uncertainty Detection Method Timeline
Fundamental Parameters        
Brane tension τ₀ 7.0 × 10¹⁹ J/m² ±15% Indirect via H₀(z) Current
Oscillation period T 2.0 Gyr ±0.3 Gyr GW spectrum 2030+
Extra dimension L 0.2 μm Factor of 2 KK modes 2035+
KK mass m_KK 1 eV ±0.5 eV Cosmological bounds Current
Cosmological Effects        
S₈ suppression -5.2% ±0.5% Weak lensing Current
w(z) amplitude A_w 0.003 ±0.001 BAO + SNe 2025+
H₀ anisotropy 0.01% ±0.005% Precision cosmology 2030+
Gravitational Waves        
Fundamental f₀ 1.6 × 10⁻¹⁷ Hz ±10% PTA arrays 2035+
Strain h_c 2 × 10⁻¹⁸ Factor of 3 SKA-PTA 2035+
Spectral index n_t 2/3 ±0.1 NANOGrav+ 2025+
Galactic Scale        
MOND a₀ 1.1 × 10⁻¹⁰ m/s² ±5% Galaxy dynamics Current
Halo core radius ~10 kpc ±3 kpc Stellar kinematics 2025+
Subhalo reduction Factor 2-3 ±50% Stream gaps 2028+
Particle Physics        
Branon mass ~1 eV Order of magnitude Non-detection Current
DM cross-section < 10⁻⁴⁸ cm² Lower limit Direct detection Current
LHC production < 10⁻⁵⁰ fb Upper limit Collider searches Current

5.2 Unique Signatures

  1. No Direct Detection: The model predicts null results in all particle DM searches (XENON, LUX, etc.)

  2. Gravitational Wave Spectrum:
    • Doublet at $(f_0, 2f_0)$ with strain $h_c \sim 2 \times 10^{-18}$
    • Phase transition background at nHz frequencies
    • Detectable by SKA-PTA + LISA (2035+)
  3. Modified Halo Structure:
    • Fewer subhalos than ΛCDM (factor ~2-3)
    • Smoother density profiles (no cusps)
    • Testable via stellar streams and microlensing
  4. Spatial Gravity Variations:
    • $\delta g/g \sim 10^{-8}$ at supercluster boundaries
    • Directional H₀ variations ~0.01%
    • Future precision astrometry tests
  5. Baryon-DM Coupling:
    • Tighter correlation than ΛCDM expects
    • Deviations in ultra-diffuse galaxies
    • Predictable from baryon distribution alone

5.3 Falsification Criteria

The model would be falsified by:

  • Direct detection of DM particles with $\sigma > 10^{-48}$ cm²
  • Absence of GW doublet with sensitivity $< 10^{-19}$
  • Discovery of DM-dominated structures without baryons
  • Variations in fundamental constants beyond $ \dot{G}/G > 10^{-13}$ yr⁻¹

5.4 Quantum Loop Corrections and Stability

Quantum Corrections to Brane Tension

The quantum stability of the oscillating brane requires careful analysis. One-loop corrections to the effective brane tension are:

\[\delta\tau_{1-loop} = \frac{\Lambda_{UV}^4}{(4\pi)^2} \ln\left(\frac{\Lambda_{UV}}{m_\phi}\right)\]

where $\Lambda_{UV}$ is the UV cutoff and $m_\phi \sim 1$ eV is the radion mass.

Key result: For $\Lambda_{UV} < M_5$ (the 5D Planck mass), corrections remain small: \(\frac{\delta\tau_{1-loop}}{\tau_0} < 10^{-3}\)

This ensures quantum corrections don’t destabilize the classical oscillation.

Branon Properties

The quantum excitations of the brane (branons) have:

  • Mass: $m_{branon} \approx 1$ eV (set by extra dimension size $L \sim 0.2 \mu$m)
  • Coupling: Only gravitational, suppressed by $M_P^{-2}$
  • Lifetime: $\tau_{branon} > 10^{30}$ years (cosmologically stable)
  • Production rate: Negligible in colliders due to gravitational coupling

Prediction: No branon production at LHC energies ($\sigma < 10^{-50}$ fb)

Decay Rate Analysis

The oscillation mode decay rate via graviton emission:

\[\Gamma_{decay} = \frac{m_\phi^5}{M_5^3} \approx 10^{-70} \text{ Hz}\]

Since $\Gamma_{decay} \ll H_0 \approx 10^{-18}$ Hz, the oscillations persist through cosmic time.