Conformal GUT inflation, proton lifetime and non-thermal leptogenesis - The European Physical Journal C November 2019, 79:945

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Great top super work, from the resilience, effort, commitment, dedication of Sravan Kumar. Bridging particle physics to string HEP. Really top-notch.  I learned immensely from him. Thanks!!!

The European Physical Journal C

November 2019, 79:945| Cite as

Conformal GUT inflation, proton lifetime and non-thermal leptogenesis

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• K. Sravan Kumar
• Paulo Vargas Moniz

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Open Access

Regular Article - Theoretical Physics

First Online: 19 November 2019

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Abstract

In this paper, we generalize Coleman–Weinberg (CW) inflation in grand unified theories (GUTs) such as SU(5)$\text{SU}(5)$ and SO(10)$\text{SO}(10)$ by means of considering two complex singlet fields with conformal invariance. In this framework, inflation emerges from a spontaneously broken conformal symmetry. The GUT symmetry implies a potential with a CW form, as a consequence of radiative corrections. The conformal symmetry flattens the above VEV branch of the CW potential to a Starobinsky plateau. As a result, we obtain ns∼1−2N$n_s\sim 1-\frac{2}{N}$ and r∼12N2$r\sim \frac{12}{N^2}$ for N∼$N\sim$ 50–60 e-foldings. Furthermore, this framework allow us to estimate the proton lifetime as τp≲1040${\tau }_p\lesssim {10}^{40}$ years, whose decay is mediated by the superheavy gauge bosons. Moreover, we implement a type I seesaw mechanism by weakly coupling the complex singlet, which carries two units of lepton number, to the three generations of singlet right handed neutrinos (RHNs). The spontaneous symmetry breaking of global lepton number amounts to the generation of neutrino masses. We also consider non-thermal leptogenesis in which the inflaton dominantly decays into heavy RHNs that sources the observed baryon asymmetry. We constrain the couplings of the inflaton field to the RHNs, which gives the reheating temperature as 106 GeV≲TR<109${10}^6\text{ GeV}\lesssim T_R<{10}^9$ GeV.