D-term inflation in braneworld models: Consistency with cosmic-string bounds and early-time Hubble tension resolving models

We revisit D-term inflation with the bounds of the cosmic string tension from gravitational wave observations and consider the possible deviation of the spectral index compared with the ?CDM model in light of prerecombination resolutions of the Hubble tension. D-term inflation requires very small coupling constants under these constraints. We show that natural coupling constants (g = A = 0.1) can be achieved in the case of D-term inflation on the brane.

Automated summary

In this paper, we revisit D-term inflation and provide bounds on the cosmic string tension using gravitational wave observations. We also consider the possible deviation of the spectral index compared with the ΛCDM model in light of prerecombination resolutions of the Hubble tension. Our study shows that D-term inflation requires very small coupling constants under these constraints, and we demonstrate that natural coupling constants (g = A = 0.1) can be achieved in the case of D-term inflation on the brane.