5 papers
Statistically-Anisotropic Tensor Bispectrum from Inflation
Takashi Hiramatsu, Kai Murai, Ippei Obata +1
We develop a possibility of generating tensor non-Gaussianity in a kind of anisotropic inflation, where a gauge field is kinetically coupled to a spectator scalar field. Owi…
Probing Axion-like Particles via CMB Polarization
Tomohiro Fujita, Yuto Minami, Kai Murai +1
Axion-like particles (ALPs) rotate the linear polarization of photons through the ALP-photon coupling and convert the cosmic microwave background (CMB) -mode to the -mode. We…
Big-bang nucleosynthesis with sub-GeV massive decaying particles
Masahiro Kawasaki, Kazunori Kohri, Takeo Moroi +2
We consider the effects of the injections of energetic photon and electron (or positron) on the big-bang nucleosynthesis. We study the photodissociation of light elements in the ea…
Big Bang Nucleosynthesis constraints on sterile neutrino and lepton asymmetry of the Universe
Graciela B. Gelmini, Masahiro Kawasaki, Alexander Kusenko +2
We consider the cosmological effects of sterile neutrinos with the masses of MeV. The decay of sterile neutrinos changes the thermal history of the Universe and affects…
Formation of supermassive primordial black holes by Affleck-Dine mechanism
Masahiro Kawasaki, Kai Murai
We study the supermassive black holes (SMBHs) observed in the galactic centers. Although the origin of SMBHs has not been well understood yet, previous studies suggest that seed bl…