Shifted ? -hybrid inflation, gravitino dark matter, and observable gravity waves

We investigate supersymmetric hybrid inflation in a realistic model based on the gauge symmetry $SU(4)_c \times SU(2)_L SU(2)_R$. The minimal standard (MSSM) $\mu$ term arises, following Dvali, Lazarides, and Shafi, from coupling of MSSM electroweak doublets to singlet superfield which plays an essential role inflation. primordial monopoles are inflated away by arranging that SU(2)_R$ is broken along inflationary trajectory. interplay between (above) coupling, gravitino mass, reheating discussed detail. explore regions parameter space yield dark matter observable gravity waves with tensor-to-scalar ratio $r \sim 10^{-4}-10^{-3}$.