arXiv subjects

Seishi Enomoto

Publications and source records attributed to Seishi Enomoto.

25 records · Page 2Linked to original sources

arXiv2015

Influence of interactions on particle production induced by time-varying mass terms

We have investigated effects of interaction terms on non-perturbative particle production. It is well known that time-varying masses induce abundant particle production. In this paper we have shown that it is possible to induce particle production even if the mass term of a particle species is not varying in time. Such particles are produced through the interactions with other fields, whose mass terms are varying due to a time-dependent background. The necessary formalism has been introduced and analytic and numerical calculations have been performed in a simple but illustrative model. The rather general result is that the amount of produced particles without time-dependent masses can be comparable with the particle density produced directly by the varying background if the strength of interaction terms is reasonably large.

hep-ph↗

arXiv2015

Preheating with higher dimensional interaction

Particle production caused by the oscillation after inflation is important since it explains reheating after inflation. On the particle theory side, we know that effective action may have additional higher dimensional terms (usually called non-renormalizable terms) suppressed by the cut-off scale. Moreover, interaction between inflaton and so-called moduli field will be higher dimensional. Therefore, if such higher dimensional interaction is significant for resonant particle production, one cannot avoid the effect in preheating study. We explicitly calculated the required number of oscillation for the energy transfer. Consequently, cosmological history of an oscillating field and the moduli problem can be reconsidered.

hep-ph↗

arXiv2014

Beauty is more attractive: Particle Production and Moduli trapping with Higher Dimensional Interaction

We study quantum effects on moduli dynamics arising from particle production near the enhanced symmetry point (ESP). We focus on non-renormalizable couplings between the moduli field and the field that becomes light at the ESP. Considering higher dimensional interaction, we find that particle production is significant in a large area, which is even larger than the area that is expected from a renormalizable interaction. It is possible to find this possibility from a trivial adiabatic condition; however the quantitative estimation of particle production and trapping of the field in motion are far from trivial. In this paper we study particle production and trapping in detail, using both the analytical and numerical calculations, to find a clear and intuitive result that supports trapping in a vast variety of theories. Our study shows that trapping driven by a non-renormalizable interaction is possible. This possibility has not been considered in previous works. Some phenomenological models of particle physics will be mentioned to complement discussion.

hep-ph↗

arXiv2013

Modulated decay in the multi-component Universe

The early Universe after inflation may have oscillations, kinations (nonoscillatory evolution of a field), topological defects, relativistic and non-relativistic particles at the same time. The Universe whose energy density is a sum of those components can be called the multi-component Universe. The components, which may have distinguishable density scalings, may decay modulated. In this paper we study generation of the curvature perturbations caused by the modulated decay in the multi-component Universe.

hep-ph↗

arXiv2013

Non-Gaussianity in the inflating curvaton

Inflating curvaton can create curvature perturbation when the curvaton density is slowly varying. Using the delta-N formalism, we discuss the evolution of the curvature perturbation during curvaton inflation and find analytic formulation of the non-Gaussianity parameter. We first consider the inflating curvaton with sufficiently long inflationary expansion. Then we compare the result with short curvaton inflation.

hep-ph↗

arXiv2013

Curvaton mechanism after multi-field inflation

The evolution of the curvature perturbation after multi-field inflation is studied in the light of the curvaton mechanism. Past numerical studies show that many-field inflation causes significant evolution of the curvature perturbation after inflation, which generates significant non-Gaussianity at the same time. We reveal the underlying mechanism of the evolution and show that the evolution is possible in a typical two-field inflation model.

hep-ph↗

arXiv2011

Baryogenesis by B - L generation due to superheavy particle decay

We have shown that the $B-L$ generation due to the decay of the thermally produced superheavy fields can explain the Baryon assymmetry in the universe if the superheavy fields are heavier than $10^{13-14}$ GeV. Note that although the superheavy fields have non-vanishing charges under the standard model gauge interactions, the thermally prduced baryon asymmetry is sizable. The $B-L$ violating effective operators induced by integrating the superheavy fields have dimension 7, while the operator in the famous leptogenesis has dimension 5. Therefore, the constraints from the nucleon stability can be easily satisfied.

hep-ph↗