We show that the conformal coupling between the Starobinsky scalaron and matter, arising naturally in R+R2 gravity, provides a physical mechanism for the cosmological constant. The energy transfer is derived from the action, not postulated. The effective dissipation rate is determined by the scalaron dynamics. Numerical integration using the CLASS Boltzmann solver confirms that the model reproduces ΛCDM to a precision of g ≈ 5×10−9, with residuals of order 10−6% in all observables — the CMB power spectrum, matter power spectrum, and BAO distances. The cosmological constant is thereby identified as the cumulative energy transferred from matter to the scalaron since recombination. The framework predicts matter–dark-energy perturbation correlations absent in ΛCDM.
Oussama Rimouche (Sat,) studied this question.