Updating GUT-Scale Pole Higgs Inflation After ACT DR6

We consider models of chaotic inflation driven by the real parts of a conjugate pair of Higgs superfields involved in the spontaneous breaking of a grand unification symmetry at a scale assuming its value within MSSM. We combine a superpotential, which is uniquely determined by applying a continuous R symmetry, with two fractional shift-symmetric Kaehler potentials introducing two free parameters (p,N). The inflationary observables provide an excellent match to the recent ACT data for 1.355<=p<=6.7 and 6x10^-5<= N<=0.7. The attainment of inflation allows for subplanckian inflaton values and possibly detectable primordial gravitational waves with (p,N) values of order unity. A solution to the mu problem of MSSM and baryogenesis via non-thermal leptogenesis can be also accommodated by embedding the model into a B-L extension of MSSM.

💡 Research Summary

The paper presents a supersymmetric (SUGRA) model of chaotic inflation in which the inflaton is identified with the real part of a conjugate pair of Higgs superfields that break a grand‑unified B‑L symmetry at the GUT scale. The superpotential is uniquely fixed by a continuous R‑symmetry to
 W = λ S(Φ̄ Φ − M²/2) ,
where S is a singlet, Φ and Φ̄ belong to conjugate representations of the gauge group G = G_SM × U(1)_{B‑L}, λ>0 and M≪1 (in reduced Planck units). Two fractional shift‑symmetric Kähler potentials are introduced:

 K₁ = N (1 − |Φ|² − |Φ̄|²)^p ,
 K₂ = N