Cosmological Tensions and the Transitional Planck Mass Model

Understand

In this followup analysis, we update previous constraints on the Transitional Planck Mass (TPM) modified gravity model using the latest version of EFTCAMB and provide new constraints using SPT and Planck anisotropy data along with Planck CMB lensing, BAO, SNe Ia, and an $H_0$ prior from local measurements.

• We find that large shifts in the Planck mass lead to large suppression of power on small scales that is disfavored by both SPT and Planck.
• Using only SPT TE-EE data, this suppression of power can be compensated for by an upward shift of the scalar index to $n_s = 1.003 \pm 0.016$ resulting in $H_0 = 71.94^{+0.86}_{-0.85}$ kms$^{-1}$Mpc$^{-1}$ and a $\sim7\%$ shift in the Planck mass.
• Including Planck TT $\ell \leq 650$ and Planck TE-EE data restricts the shift to be $<5\%$ at $2\sigma$ with $H_0 = 70.65 \pm 0.66$ kms$^{-1}$Mpc$^{-1}$.