88 citations · 651 across the 24 of their papers we have counts for
24 papers
Stochastic effects on observation of ultralight bosonic dark matter
Hiromasa Nakatsuka, Soichiro Morisaki, Tomohiro Fujita +4
Ultralight bosonic particles are fascinating candidates of dark matter (DM). It behaves as classical waves in our Galaxy due to its large number density. There have been various me…
Is cosmic birefringence due to dark energy or dark matter? A tomographic approach
Hiromasa Nakatsuka, Toshiya Namikawa, Eiichiro Komatsu
A pseudoscalar "axionlike" field, , may explain the hint of cosmic birefringence observed in the power spectrum of the cosmic microwave background (CMB) polarization d…
Inflation with two-form field: the production of primordial black holes and gravitational waves
Tomohiro Fujita, Hiromasa Nakatsuka, Ippei Obata +1
Antisymmetric tensor field (two-form field) is a ubiquitous component in string theory and generally couples to the scalar sector through its kinetic term. In this paper, we propos…
Anisotropies in Cosmological 21 cm Background by Oscillons/I-balls of Ultra-light Axion-like Particle
Masahiro Kawasaki, Kazuyoshi Miyazaki, Kai Murai +2
Ultra-light axion-like particle (ULAP) with mass has recently been attracting attention as a possible solution to the small-scale crisis. ULAP forms…
Ultralight dark matter searches with KAGRA gravitational wave telescope
Yuta Michimura, Tomohiro Fujita, Jun'ya Kume +5
Among various dark matter candidates, bosonic ultralight fields with masses below 1~eV are well motivated. Recently, a number of novel approaches have been put forward to search fo…
First observation and analysis of DANCE: Dark matter Axion search with riNg Cavity Experiment
Yuka Oshima, Hiroki Fujimoto, Masaki Ando +9
Dark matter Axion search with riNg Cavity Experiment (DANCE) was proposed to search for axion dark matter [Phys. Rev. Lett. 121, 161301 (2018)]. We aim to detect the rotation and o…
Constraints on small-scale primordial density fluctuation from cosmic microwave background through dark matter annihilation
Masahiro Kawasaki, Hiromasa Nakatsuka, Kazunori Nakayama
The cosmic microwave background (CMB) observation by the Planck satellite precisely determines primordial curvature fluctuations on larger scales than …
Gauge Field Production and Schwinger Reheating in Runaway Axion Inflation
Soichiro Hashiba, Kohei Kamada, Hiromasa Nakatsuka
In a class of (pseudoscalar) inflation, inflationary phase is followed by a kination phase, where the Universe is dominated by the kinetic energy of the inflaton that runs away in…
Free Streaming Length of Axion-Like Particle After Oscillon/ I-ball Decays
Kaname Imagawa, Masahiro Kawasaki, Kai Murai +2
Axion-like particles (ALPs) are pseudoscalar bosons predicted by string theory. The ALPs have a shallower potential than a quadratic one, which induces the instability and can form…
SU()-natural inflation
Tomohiro Fujita, Kyohei Mukaida, Kai Murai +1
We study SU() gauge fields that couple to the inflaton through the Chern-Simons term. We provide a general procedure to construct homogeneous, isotropic, and attractor solutions…
Strong clustering of primordial black holes from Affleck-Dine mechanism
Masahiro Kawasaki, Kai Murai, Hiromasa Nakatsuka
Primordial black hole (PBH) is a fascinating candidate for the origin of binary merger events observed by LIGO-Virgo collaboration. The spatial distribution of PBHs at formation is…
Axion dark matter search using arm cavity transmitted beams of gravitational wave detectors
Koji Nagano, Hiromasa Nakatsuka, Soichiro Morisaki +3
Axion is a promising candidate for ultralight dark matter which may cause a polarization rotation of laser light. Recently, a new idea of probing the axion dark matter by optical l…
Revisiting CMB constraints on dark matter annihilation
Masahiro Kawasaki, Hiromasa Nakatsuka, Kazunori Nakayama +1
The precision measurements of the cosmic microwave background power spectrum put a strong constraint on the dark matter annihilation cross section since the electromagnetic energy…
Gravitational waves from type II axion-like curvaton model and its implication for NANOGrav result
Masahiro Kawasaki, Hiromasa Nakatsuka
The recent report of NANOGrav is gathering attention since its signal can be explained by the stochastic gravitational waves (GWs) with at H…
Detection of isotropic cosmic birefringence and its implications for axion-like particles including dark energy
Tomohiro Fujita, Kai Murai, Hiromasa Nakatsuka +1
We investigate the possibility that axion-like particles (ALPs) with various potentials account for the isotropic birefringence recently reported by analyzing the Planck 2018 polar…
Improved sensitivity of interferometric gravitational wave detectors to ultralight vector dark matter from the finite light-traveling time
Soichiro Morisaki, Tomohiro Fujita, Yuta Michimura +2
Recently several studies have pointed out that gravitational-wave detectors are sensitive to ultralight vector dark matter and can improve the current best constraints given by the…
Probing Oscillons of Ultra-Light Axion-like Particle by 21cm Forest
Masahiro Kawasaki, Wakutaka Nakano, Hiromasa Nakatsuka +1
Ultra-Light Axion-like Particle (ULAP) is motivated as one of the solutions to the small scale problems in astrophysics. When such a scalar particle oscillates with an $\mathcal{O}…
Oscillons of Axion-Like Particle: Mass distribution and power spectrum
Masahiro Kawasaki, Wakutaka Nakano, Hiromasa Nakatsuka +1
In string theory, the simultaneous existence of many Axion-Like Particles (ALPs) are suggested over a vast mass range, and a variety of potentials have been developed in the contex…
Ultralight vector dark matter search with auxiliary length channels of gravitational wave detectors
Yuta Michimura, Tomohiro Fujita, Soichiro Morisaki +2
Recently, a considerable amount of attention has been given to the search for ultralight dark matter by measuring the oscillating length changes in the arm cavities of gravitationa…
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…
Generation of Primordial Black Holes and Gravitational Waves from Dilaton-Gauge Field Dynamics
Masahiro Kawasaki, Hiromasa Nakatsuka, Ippei Obata
We study the observational signatures from particle production of a gauge field kinetically coupled to an inflaton. Regarding the form of gauge kinetic function, we consider…
Q-ball decay through A-term in the gauge-mediated SUSY breaking scenario
Masahiro Kawasaki, Hiromasa Nakatsuka
Q-balls are non-topological solitons whose classical stability is ensured by a global charge. In particular, Q-balls are produced in the framework of the Affleck-Dine baryog…
Effect of nonlinearity between density and curvature perturbations on the primordial black hole formation
Masahiro Kawasaki, Hiromasa Nakatsuka
We study the effect of the nonlinear relation between density and curvature perturbations on the formation of PBHs. By calculating the variance and skewness of the density perturba…
Formation of primordial black holes in an axionlike curvaton model
Kenta Ando, Masahiro Kawasaki, Hiromasa Nakatsuka
We performed the detailed analysis of the primordial black hole (PBH) formation mechanism in an axionlike curvaton model with a coupling to inflaton. The phase direction of the com…