Sneutrino Tribrid Inflation in Flipped SU(5): Confronting ACT DR6 and Planck Observations
Abstract
We construct a realization of sneutrino tribrid inflation within the R-symmetric flipped SU(5) grand unified theory. A vector-like pair of matter multiplets, 10V+10̅V, provides a D-flat inflaton direction along the right-handed sneutrino component, with an additional Z2 symmetry forbidding a direct inflaton mass term so that the leading inflationary interaction is a non-renormalizable Kähler-driven operator. Unlike previous studies, we treat the superpotential cutoff scale Ms as independent of the reduced Planck mass, mP, substantially enlarging the viable parameter space. Confronting the model with the ACT DR6/Planck determination ns=0.9734±0.0034 and the 2σ bound on the running of the spectral index, we identify broad regions of viable parameter space in which the flipped SU(5) symmetry-breaking scale can approach the conventional GUT scale, M≃ MGUT, and the tensor-to-scalar ratio can reach observable values, r≳10−3, within reach of forthcoming CMB B-mode experiment such as LiteBIRD. We further study the post-inflationary dynamics, identifying the inflaton with the lightest right-handed sneutrino in a conventional type-I seesaw sector, whose out-of-equilibrium decay generates a lepton asymmetry that is converted into the observed baryon asymmetry via non-thermal leptogenesis and electroweak sphalerons, for a reheating temperature consistent with both successful leptogenesis and the gravitino constraint.
Related
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BibTeX
@misc{israr2026sneutrino,
title = {{Sneutrino Tribrid Inflation in Flipped $\mathbfSU(5)$: Confronting ACT DR6 and Planck Observations}},
author = {Farishta Israr and Mansoor Ur Rehman and Saleh O. Allehabi},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2608.08708},
eprint = {2608.08708},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.08708},
}
RIS
TY - UNPB
TI - Sneutrino Tribrid Inflation in Flipped SU(5): Confronting ACT DR6 and Planck Observations
AU - Farishta Israr
AU - Mansoor Ur Rehman
AU - Saleh O. Allehabi
PY - 2026
DA - 2026/10/07
PB - arXiv
DO - 10.48550/arxiv.2608.08708
UR - https://arxiv.org/abs/2608.08708
AB - We construct a realization of sneutrino tribrid inflation within the R-symmetric flipped SU(5) grand unified theory. A vector-like pair of matter multiplets, 10_V+10̅_V, provides a D-flat inflaton direction along the right-handed sneutrino component, with an additional Z_2 symmetry forbidding a direct inflaton mass term so that the leading inflationary interaction is a non-renormalizable Kähler-driven operator. Unlike previous studies, we treat the superpotential cutoff scale M_s as independent of the reduced Planck mass, m_P, substantially enlarging the viable parameter space. Confronting the model with the ACT DR6/Planck determination n_s=0.9734±0.0034 and the 2σ bound on the running of the spectral index, we identify broad regions of viable parameter space in which the flipped SU(5) symmetry-breaking scale can approach the conventional GUT scale, M≃ M_GUT, and the tensor-to-scalar ratio can reach observable values, r≳10^−3, within reach of forthcoming CMB B-mode experiment such as LiteBIRD. We further study the post-inflationary dynamics, identifying the inflaton with the lightest right-handed sneutrino in a conventional type-I seesaw sector, whose out-of-equilibrium decay generates a lepton asymmetry that is converted into the observed baryon asymmetry via non-thermal leptogenesis and electroweak sphalerons, for a reheating temperature consistent with both successful leptogenesis and the gravitino constraint.
ER -