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arXiv · 1910.07554

Pseudosmooth Tribrid Inflation in $SU(5)$

Muhammad Atif Masoud·Mansoor Ur Rehman·Qaisar Shafi
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Abstract

A realistic tribrid model of sneutrino inflation is constructed in an $R$-symmetric $SU(5)$ grand unified theory (GUT). To avoid the monopole problem, a pseudosmooth inflationary trajectory is generated with the help of an additional $Z_5$ symmetry which is broken during and after inflation. The predictions of inflationary parameters are made at the central value of the scalar spectral index, $n_s =0.968$. The largest possible value of the tensor to scalar ratio, $r\lesssim 0.0027$, is obtained with sub-Planckian field values ($\lesssim m_P$). A successful realization of reheating and leptogenesis is achieved by avoiding the gravitino problem with a reheat temperature as low as $10^6$ GeV. The predicted range of the gauge symmetry breaking scale, $ 5 \times 10^{16} \lesssim M/\text{GeV} \lesssim 5 \times 10^{17}$, turns out to be somewhat larger than the typical GUT scale. With additional vector-like families, a successful gauge coupling unification is achieved by avoiding the no-go theorem related to $R$-symmetric $SU(5)$ GUT.

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Muhammad Atif Masoud, Mansoor Ur Rehman, Qaisar Shafi. 2019-10-16. Pseudosmooth Tribrid Inflation in $SU(5)$. https://doi.org/10.1088/1475-7516%2F2020%2F04%2F041

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