Viability of complex self-interacting scalar field as dark matter

Abstract

We study the viability of a complex scalar field $\chi$ with self-interacting potential $V=m_0^{\chi }/2|\chi {|}^2+h|\chi {|}^4$ as dark matter. The scalar field is produced at reheating through the decay of the inflaton field and then, due to the self-interaction, a Bose-Einstein condensate of $\chi$ particles forms. The condensate represents dark matter in that model. We analyze the cosmological evolution of the model, stressing how, due to the presence of the self-interaction, the model naturally admits dark matter domination at late times, thus avoiding any fine tuning on the energy density of the scalar field at early times. Finally we give a lower bound for the size of dark matter halos at present time and we show that our model is compatible with dark matter halos greater than $0.1Kpc$ and with BBN and CMB bounds on the effective number of extra neutrinos ${\Delta }_{\nu }^{eff}$. Therefore, the model is viable and for $h\simeq 10^{-4}-10^{-12}$ one obtains a mass $m^{\chi }\simeq m_0^{\chi }\simeq 1-10^{-2}eV$ for dark matter particles from radiation-matter equality epoch to present time, but at temperatures $T_{\gamma }\gg 10eV$, where $T_{\gamma }$ is the photons temperature, thermal corrections to $m_0^{\chi }$ due to the self-coupling $h$ are dominant.

7 pages, some reference added

References in corpus (3)

• Cosmological Constraints from the SDSS Luminous Red Galaxies
• Dark Matter Candidates: A Ten-Point Test
• Are galaxies extending?

Cited by in corpus (1)

• Two-fluid dark matter models