Sneutrino tribrid inflation, metastable cosmic strings and gravitational waves

Abstract We present a successful realization of sneutrino tribrid inflation model based on gauged U(1)_B-L extension Minimal Supersymmetric Standard Model (MSSM). A single interaction term involving the B-L Higgs field and right-handed neutrinos serves multiple purposes. These include generation heavy Majorana masses for to provide an explanation tiny neutrino via seesaw mechanism, realistic scenario reheating non-thermal leptogenesis with reheat temperature as low 10 6 GeV, inflaton. The matter parity which helps avoid rapid proton decay survives Z 2 subgroup U(1) R-symmetry. Depending choice parameters yields following predicted range tensor scalar ratio, 3 × -11 ≲ r≲ 7× -4 (6 -7 r 0.01), running spectral index, -0.00022 dn_s/dln k -0.0026 (-0.00014 0.005), along breaking scale, 14 M/ GeV≲ 5 15 16 ), calculated at central value n_s =0.966, reported by Planck 2018. possibility realizing metastable cosmic strings in grand unified theory setup is briefly discussed. string network admits tension values -8 Gμ s -6 , predicts stochastic gravitational wave background lying within 2-σ bounds recent NANOGrav 12.5-yr data.