Kinetically modified nonminimal Higgs inflation in supergravity

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 supersymmetric value. We combine a superpotential, which is uniquely determined by applying a continuous R symmetry, with a class of logarithmic or semilogarithmic Kahler potentials which exhibit a prominent shift symmetry with a tiny violation, whose strengths are quantified by c(-) and c(-). The inflationary observables provide an excellent match to the recent BICEP2/Keck Array and Planck results, setting 3.5 x 10(-3). less than or similar to r(+/-) = c(+) / c(-) less than or similar to 1/N, where N = 3 or 2 is the prefactor of the logarithm. Inflation can be attained for sub-Planckian inflaton values, with the corresponding effective theories retaining the perturbative unitarity up to the Planck scale.