W - M Phantom Transition At Z(T) < 0.1 As A Resolution Of The Hubble Tension

Arapid phantom transition of the dark energy equation of state parameter w at a transition redshift z(t) < 0.1 of the form w(z) = 1 + Delta w Theta(z(t) - z) with Delta w < 0 can lead to a higher value of the Hubble constant while closely mimicking a Planck18/Lambda CDM form of the comoving distance r(z) = integral(z)(0)dz'/H(z') for z > z(t). Such a transition however would imply a significantly lower value of the SnIa absolute magnitude M than the value MC imposed by local Cepheid calibrators at z < 0.01. Thus, in order to resolve the H-0 tension it would need to be accompanied by a similar transition in the value of the SnIa absolute magnitude M as M (z) = M-C + Delta M Theta(z - z(t)) with Delta M < 0. This is a late w - M phantom transition (LwMPT). It may be achieved by a sudden reduction of the value of the normalized effective Newton constant mu = G(eff)/G(N) by about 6% assuming that the absolute luminosity of SnIa is proportional to the Chandrasekhar mass which varies as mu(-3/2). We demonstrate that such an ultra low z abrupt feature of w - M provides a better fit to cosmological data compared to smooth late time deformations of H(z) that also address the Hubble tension. For z(t) = 0.02 we find Delta w similar or equal to-4, Delta M similar or equal to-0.1. This model also addresses the growth tension due to the predicted lower value of mu at z > z(t). A prior of Delta w = 0 (no w transition) can still resolve the H-0 tension with a larger amplitude M transition with Delta(M) similar or equal to -0.2 at z(t) similar or equal to 0.01. This implies a larger reduction of mu for z > 0.01 (about 12%). The LwMPT can be generically induced by a scalar field nonminimally coupled to gravity with no need of a screening mechanism since in this model mu = 1 at z < 0.01.