A unified composite model of inflation and dark matter in the Nambu-Jona-Lasinio theory

Abstract

In this work, we propose a cosmological scenario inherently based on the effective Nambu-Jona-Lasinio (NJL) model that cosmic inflation and dark matter can be successfully described by a single framework. On the one hand, the scalar channel of the NJL model plays a role of the composite inflaton (CI) and we show that it is viable to achieve successful inflation via a non-minimal coupling to gravity. For model of inflation, we compute the inflationary parameters and confront them with recent Planck 2015 data. We discover that the predictions of the model are in excellent agreement with the Planck analysis. We also present in our model a simple connection of physics from the high scales to low scales via renormalization group equations of the physical parameters. On the other hand, the pseudoscalar channel can be assigned as a candidate for composite dark matter (CD). For model of dark matter, we couple the pseudoscalar to the Higgs sector of the standard model with the coupling strength $\kappa$ and estimate its thermally-averaged relic abundance. We discover that the CD mass is strongly sensitive to the coupling $\kappa$. We find in case of light CD, $M_{s} M_{W,\,Z}$ (or $>M_{h}$), the required relic abundance can be satisfied for value of the CD mass $M_{s}\sim 410\,{\rm GeV}$ for $\kappa = 0.5$. In contradiction to the light mass case, however, the CD mass in this case can even be heavier when the coupling is getting larger.