Ayuki Kamada

Coherent propagation of PeV neutrinos and the dip in the neutrino spectrum at IceCube

The energy spectrum of high-energy neutrinos reported by the IceCube Collaboration shows a dip between 400 TeV and 1 PeV. One intriguing explanation is that high-energy neutrinos scatter with the cosmic neutrino background through an

Mixed (cold+warm) dark matter in the bino-wino coannihilation scenario

\ensuremath{\sim}\mathrm{MeV}

Structure formation in a mixed dark matter model with decaying sterile neutrino: the 3.5 keV X-ray line and the Galactic substructure

mediator. Taking the density matrix approach, we develop a formalism to study the propagation of PeV neutrinos in the presence of the new neutrino interaction. If the interaction is flavored such as the gauged

Affleck-Dine Baryogenesis and Dark Matter Production after High-scale Inflation

{L}_{\ensuremath{\mu}}\ensuremath{-}{L}_{\ensuremath{\tau}}

SIMP from a strong U(1) gauge theory with a monopole condensation

model we consider, the resonant collision may not suppress the PeV neutrino flux completely. The new force mediator may also contribute to the number of effectively massless degrees of freedom in the early Universe and change the diffusion time of neutrinos from the supernova core. Astrophysical observations such as big bang nucleosynthesis and supernova cooling provide an interesting test for the explanation.

Constraints on mixed dark matter from anomalous strong lens systems

We study phenomenological aspects of the bino-wino co-annihilation scenario in high-scale supersymmetry breaking models. High-scale SUSY breaking scenarios are considered to be promising possibility after the discovery of the Higgs boson with a mass around 126GeV. In this paper, we discuss the bino lightest supersymmetric particle (LSP) accompanied by the at most around 30GeV heavier wino. With the suitable mass splitting between the bino and the wino, the bino LSP has the correct relic abundance of dark matter. For the smaller mass splitting, the late-time decay of the gravitino can provide the correct abundance of the bino dark matter. It is extremely challenging to find signals from the bino dark matter in direct and indirect detections. By utilizing multi-jets plus missing transverse momentum events at the LHC, we can constraint the gluino mass and thus probe the bino-wino co-annihilation scenario indirectly. The collider experiment, however, can not search the bino dark matter directly. In this paper, we suggest the direct probe of the bino dark matter. We show that the bino dark matter leaves imprints on the smallscale matter power spectrum when the bino dark matter is produced by the decay of the gravitino. The non-thermal bino dark matter behaves as mixed (cold+warm) dark matter.

Cosmological Constraint on the Light Gravitino Mass from CMB Lensing and Cosmic Shear

We perform a set of cosmological simulations of structure formation in a mixed dark matter (MDM) model. Our model is motivated by the recently identified

Axionlike particle assisted strongly interacting massive particle

3.5\,{\rm keV}

Solution to the baryon–dark-matter coincidence problem in the constrained minimal supersymmetric model with a 126-GeV Higgs boson

X-ray line, which can be explained by the decay of non-resonantly produced sterile neutrinos accounting for

Opening the window to the cogenesis with Affleck-Dine mechanism in gravity mediation

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