Predicting the Cosmic Microwave Background from Conformal Bimetric Cosmology in Cl(10,2)

We derive predictions for the cosmic microwave background (CMB) angularpower spectrum from conformal bimetric cosmology formulated in the geometricalgebra Cl(10, 2). The bimetric model, in which a positive-mass sector is coupled toa negative-mass sector through the conformal connection [11], replaces dark matterand dark energy by the gravitational eects of the second sector. When formulatedin Cl(10, 2) = Cl(4, 2)⊗Cl(6), the model gains three structural elements absent fromtensor bimetric theories: (i) a dilaton constraint linking the two scale factors, (ii) aninternal su(4) gauge structure modifying the relativistic species count, and (iii) a ge-ometric cross-sector coupling xed by conformal symmetry rather than postulated.We derive the modied Friedmann equations, the coupled perturbation equationsin conformal Newtonian gauge, and the resulting modications to the CMB observ-ables: peak positions, peak height ratios, integrated SachsWolfe eect, dampingtail, and lensing potential. We identify ve quantitative signatures that distinguishconformal bimetric cosmology from ΛCDM and from tensor bimetric theories, andcompare them with the Planck 2018 data. The framework predicts specic devia-tions in the low-ℓ multipoles and in the relative heights of odd and even acousticpeaks. A companion numerical code implementing the modied Boltzmann hierar-chy is described.