collaborators

7 papers

astro-ph.CO2026

Reviving the Affleck-Dine Curvaton Scenario with Compensated Isocurvature Perturbations

Masahiro Kawasaki, Shunsuke Neda

We revisit the Affleck-Dine curvaton scenario in the framework of supersymmetry, taking Q-ball formation into account. In this scenario, a scalar field carrying baryon number, name…

astro-ph.CO2026

Merger rate of initially clustered primordial black holes for the two-body channel

Kentaro Kasai, Masahiro Kawasaki, Kai Murai +1

Primordial black holes (PBHs) may form an initially clustered population depending on their production mechanism. Motivated by binary black-hole merger events observed by gravitati…

astro-ph.CO2026

Microlensing events and primordial black holes in the axionlike curvaton model

Kentaro Kasai, Masahiro Kawasaki, Kai Murai +1

Recently, Subaru Hyper Suprime-Cam (HSC) observations found 12 candidates for microlensing events. These events can be explained by primordial black holes (PBHs) with masses of $10…

hep-ph2025

Formation of primordial black holes through Q-balls

Shinta Kasuya, Masahiro Kawasaki, Alexander Kusenko +1

We study the primordial black hole (PBH) formation from Q-balls that are non-topological solitons in scalar field theories. We develop a formula for calculating the density perturb…

astro-ph.CO2025

Clustering of Primordial Black Holes from QCD Axion Bubbles

Kentaro Kasai, Masahiro Kawasaki, Naoya Kitajima +3

We study the clustering of primordial black holes (PBHs) and axion miniclusters produced in the model proposed to explain the LIGO/Virgo events or the seeds of the supermassive bla…

hep-ph2025

Do Cosmic String Segments Emit Gravitational Waves?

Akifumi Chitose, Masahiro Ibe, Shunsuke Neda +1

Cosmic strings are predicted in various extensions of the Standard Model, including grand unified theories. Depending on the symmetry-breaking pattern, they can be either topologic…