@Article{Civiletti_etal2014, author="Civiletti, M. and Pallis, C. and Shafi, Q.", title="Upper bound on the tensor-to-scalar ratio in GUT-scale supersymmetric hybrid inflation", journal="Physics Letters B", year="2014", publisher="Elsevier Science Bv", volume="733", pages="276--282", abstract="We explore the upper bound on the tensor-to-scalar ratio r in supersymmetric (F-term) hybrid inflation models with the gauge symmetry breaking scale set equal to the value 2.86 . 10(16) GeV, as dictated by the unification of the MSSM gauge couplings. We employ a unique renormalizable superpotential and a quasi-canonical Kahler potential, and the scalar spectral index n(s) is required to lie within the two-sigma interval from the central value found by the Planck satellite. In a sizable region of the parameter space the potential along the inflationary trajectory is a monotonically increasing function of the inflaton, and for this case, r less than or similar to 2.9.10(-4), while the spectral index running, vertical bar dn(s)/d ln k vertical bar, can be as large as 0.01. Ignoring higher order terms which ensure the boundedness of the potential for large values of the inflaton, the upper bound on r is significantly larger, of order 0.01, for subplanckian values of the inflaton, and vertical bar dn(s)/dlnk vertical bar similar or equal to 0.006.", optnote="WOS:000336430400048", optnote="exported from refbase (https://references.ific.uv.es/refbase/show.php?record=1805), last updated on Thu, 26 Jun 2014 10:18:22 +0000", issn="0370-2693", doi="10.1016/j.physletb.2014.04.060", opturl="http://arxiv.org/abs/1402.6254", opturl="https://doi.org/10.1016/j.physletb.2014.04.060", archivePrefix="arXiv", eprint="1402.6254", language="English" }