Hybrid inflation in the complex plane

Buchmüller, W.; Domcke, V.; Schmitz, K.; Kamada, K.

doi:10.1088/1475-7516/2014/07/054

Journal Article

PUBDB-2014-04083

Hybrid inflation in the complex plane

Buchmüller, W. (Corresponding Author)DESY* ; Domcke, V. ; Kamada, K.DESY* ; Schmitz, K.

2014
IOP London

Journal of cosmology and astroparticle physics 2014(07), 054 (2014) [10.1088/1475-7516/2014/07/054]

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Please use a persistent id in citations: doi:10.1088/1475-7516/2014/07/054 doi:10.3204/PUBDB-2014-04083

Report No.: DESY-14-005; IPMU 14-0083; SISSA 16/2014/FISI; arXiv:1404.1832

Abstract: Supersymmetric hybrid inflation is an exquisite framework to connect inflationary cosmology to particle physics at the scale of grand unification. Ending in a phase transition associated with spontaneous symmetry breaking, it can naturally explain the generation of entropy, matter and dark matter. Coupling F-term hybrid inflation to soft supersymmetry breaking distorts the rotational invariance in the complex inflaton plane — an important fact, which has been neglected in all previous studies. Based on the δ N formalism, we analyze the cosmological perturbations for the first time in the full two-field model, also taking into account the fast-roll dynamics at and after the end of inflation. As a consequence of the two-field nature of hybrid inflation, the predictions for the primordial fluctuations depend not only on the parameters of the Lagrangian, but are eventually fixed by the choice of the inflationary trajectory. Recognizing hybrid inflation as a two-field model resolves two shortcomings often times attributed to it: the fine-tuning problem of the initial conditions is greatly relaxed and a spectral index in accordance with the PLANCK data can be achieved in a large part of the parameter space without the aid of supergravity corrections. Our analysis can be easily generalized to other (including large-field) scenarios of inflation in which soft supersymmetry breaking transforms an initially single-field model into a multi-field model.

Keyword(s): inflation (LCSH) ; supersymmetry and cosmology (LCSH) ; cosmological perturbation theory (LCSH) ; initial conditions and eternal universe (LCSH) ; inflation: hybrid ; supersymmetry: symmetry breaking ; scale: grand unified theory ; supergravity: correction ; fluctuation: primordial ; rotation: invariance ; spontaneous symmetry breaking ; critical phenomena ; boundary condition ; cosmological model ; power spectrum ; perturbation ; dark matter ; trajectory ; inflaton ; entropy ; F-term