10 citations · 18 across the 8 of their papers we have counts for
9 papers
Neutrino Direct Simulation Monte Carlo: Accurate modeling of out-of-equilibrium decaying cosmological relics
Kensuke Akita, Miguel Escudero, Oleksii Ihnatenko +1
We consider nonstandard cosmologies in which decaying relics inject energy at MeV temperatures, driving neutrinos out of equilibrium. The subsequent neutrino evolution shapes predi…
Heavy neutral leptons beyond the BBN bound: probing the lepton asymmetry of the Universe
Kensuke Akita, Maksym Ovchynnikov, Vsevolod Syvolap
Hadronically decaying particles with lifetimes are excluded by Big Bang Nucleosynthesis almost independently of their abundance: the mesons from their decay…
Minimal Majoron Dark Matter
Kensuke Akita, Koichi Hamaguchi, Haruto Kitagawa +1
We study Majoron dark matter (DM) in its minimal realization, based on the Type-I seesaw framework extended by a SM-singlet complex scalar. Remaining agnostic about the origin and…
Affleck-Dine Leptoflavorgenesis
Kensuke Akita, Koichi Hamaguchi, Maksym Ovchynnikov
We propose a scenario to produce large primordial lepton flavor asymmetries with vanishing total lepton asymmetry, based on the Affleck-Dine mechanism with Q-ball formation. This s…
Dark matter explanations for the neutrino emission from the Seyfert galaxy NGC 1068
Kensuke Akita, Alejandro Ibarra, Robert Zimmermann
We investigate the possibility that the high-energy neutrino flux observed from the Seyfert galaxy NGC 1068 originates from dark matter annihilations within the density spike surro…
Maximal parameter space of sterile neutrino dark matter with lepton asymmetries
Kensuke Akita, Koichi Hamaguchi, Maksym Ovchynnikov
We delineate the maximal parameter space of sterile neutrino dark matter in the presence of lepton flavor asymmetries. We focus on large flavor asymmetries with vanishing total lep…
Dynamics of metastable Standard Model particles from long-lived particle decays in the MeV primordial plasma
Kensuke Akita, Gideon Baur, Maksym Ovchynnikov +2
We investigate the cosmological impact of hypothetical unstable new physics particles that decay in the MeV-scale plasma of the Early Universe. Focusing on scenarios where the deca…
New physics decaying into metastable particles: impact on cosmic neutrinos
Kensuke Akita, Gideon Baur, Maksym Ovchynnikov +2
We investigate decays of hypothetical unstable new physics particles into metastable species such as muons, pions, or kaons in the Early Universe, when temperatures are in the MeV…
Limits on heavy neutral leptons, bosons and majorons from high-energy supernova neutrinos
Kensuke Akita, Sang Hui Im, Mehedi Masud +1
Light hypothetical particles with masses up to can be produced in the core of supernovae. Their subsequent decays to neutrinos can produce a flux comp…