Publications (41)
Can MSSM Particle be the Inflaton?
Shinta Kasuya, Takeo Moroi, Fuminobu Takahashi
We consider the possibility of using one of the -flat directions in the minimal supersymmetric standard model (MSSM) as the inflaton. We show that the flat direction consisting…
511 keV line from Q balls in the Galactic Center
Shinta Kasuya, Fuminobu Takahashi
The 511 keV photons from the galactic center can be explained by positrons produced through Q-ball decay. In the scheme of gauge-mediated supersymmetry breaking, large Q balls with…
Surface reheating as a new paradigm
Anupam Mazumdar, Kari Enqvist, Shinta Kasuya
In this talk we briefly review the standard idea of reheating and then present a new paradigm of reheating the Universe through surface evaporation.
New observable for gravitational lensing effects during transits
Shinta Kasuya, Mitsuhiko Honda, Risa Mishima
We investigate gravitational lensing effects of an extrasolar planet transiting its host star. We focus on the `rising spikes' of the light curve just before and after the transit,…
Novel Flavon Stabilization with Trimaximal Neutrino Mixing
So Chigusa, Shinta Kasuya, Kazunori Nakayama
We construct a supersymmetric flavor symmetry model with one of the trimaximal neutrino mixing patterns, the so-called TM, by using the novel way to stabilize flavons, wh…
Axino dark matter and baryon number asymmetry from Q-ball decay in gauge mediation
Shinta Kasuya, Etsuko Kawakami, Masahiro Kawasaki
We investigate the Q-ball decay into the axino dark matter in the gauge-mediated supersymmetry breaking. In our scenario, the Q ball decays mainly into nucleons and partially into…
Parameter estimation from the transit light curve including gravitational lensing effects
Shinta Kasuya, Akihiko Fukui, Ayana Suzuki +1
We study transit light curves of exoplanets, incorporating gravitational lensing effects, and explore the possibility of estimating planetary masses using only the transit light cu…
Charge distribution of the gauge-mediation type Q ball
Shinta Kasuya, Masahiro Kawasaki
We numerically study the formation of the gauge-mediation type Q balls in the logarithmic square potential on three-dimensional lattices. We obtain the broad charge distribution of…
Detection of molecular clouds in the PeVatron candidate source LHAASO J03415258 by the Nobeyama 45-m radio telescope
Naomi Tsuji, Shunya Takekawa, Kaya Mori +8
We report a new CO observation survey of LHAASO J03415258 using the Nobeyama Radio Observatory (NRO) 45-m telescope. LHAASO J03415258 is one of the unidentified ultra-high-en…
MSSM flat direction as a curvaton
Kari Enqvist, Asko Jokinen, Shinta Kasuya +1
We study in detail the possibility that the flat directions of the Minimal Supersymmetric Standard Model (MSSM) could act as a curvaton and generate the observed adiabatic density…
Axion isocurvature fluctuations with extremely blue spectrum
Shinta Kasuya, Masahiro Kawasaki
We construct an axion model for generating isocurvature fluctuations with blue spectrum, n_{iso}=2-4, which is suggested by recent analyses of admixture of adiabatic and isocurvatu…
511 keV line and diffuse gamma rays from moduli
Shinta Kasuya, Masahiro Kawasaki
We obtain the spectrum of gamma ray emissions from the moduli whose decay into accounts for the 511 keV line observed by SPI/INTERGRAL. The moduli emit gamma rays through…
Entropy production by Q-ball decay for diluting long-lived charged particles
Shinta Kasuya, Fuminobu Takahashi
The cosmic abundance of a long-lived charged particle such as a stau is tightly constrained by the catalyzed big bang nucleosynthesis. One of the ways to evade the constraints is t…
IceCube potential for detecting Q-ball dark matter in gauge mediation
Shinta Kasuya, Masahiro Kawasaki, Tsutomu T. Yanagida
We study Q-ball dark matter in gauge-mediated supersymmetry breaking, and seek the possibility of detection in the IceCube experiment. We find that the Q balls would be the dark ma…
Flat Direction Inflation with Running Kinetic Term and Baryogenesis
Shinta Kasuya, Fuminobu Takahashi
We consider a possibility that one of the flat directions in the minimal supersymmetric standard model plays the role of the inflaton field and realizes large-field inflation. This…
Revisiting the gravitino dark matter and baryon asymmetry from Q-ball decay in gauge mediation
Shinta Kasuya, Masahiro Kawasaki, Masaki Yamada
We reinvestigate the scenario that the amount of the baryons and the gravitino dark matter is naturally explained by the decay of the Q balls in the gauge-mediated SUSY breaking. E…
Influence on Starobinsky inflation by other fields with large amplitude
Shinta Kasuya, Kanto Moritake
The Starobinsky model is one of the inflation models consistent with the result of CMB observation by the Planck satellite. We consider the dynamics of the Starobinsky inflation in…
Gravitino dark matter and baryon asymmetry from Q-ball decay in gauge mediation
Shinta Kasuya, Masahiro Kawasaki
We investigate the Q-ball decay in the gauge-mediated SUSY breaking. Q balls decay mainly into nucleons, and partially into gravitinos, while they are kinematically forbidden to de…
Formation of the Q ball in the thermal logarithmic potential and its properties
Shinta Kasuya
We investigate the Q-ball formation in the thermal logarithmic potential by means of the lattice simulation, and reconfirm qualitatively the relation between Q-ball charge and the…
Inflatonic Solitons In Running Mass Inflation
Kari Enqvist, Shinta Kasuya, Anupam Mazumdar
The inflaton condensate associated with a global symmetry can fragment into quasistable Q balls, provided the inflaton oscillations give rise to an effective equation of state with…
Revisiting oscillon formation in KKLT scenario
Shinta Kasuya, Masahiro Kawasaki, Francis Otani +1
KKLT scenario has succeeded in stabilizing the volume modulus and constructing metastable de Sitter (dS) vacua in type IIB string theory. We revisit to investigate the possibility…
Q-ball dark matter and baryogenesis in high-scale inflation
Shinta Kasuya, Masahiro Kawasaki
We investigate the scenario that one flat direction creates baryon asymmetry of the unverse, while Q balls from another direction can be the dark matter in the gauge-mediated super…
Quadratic chaotic inflation with a logarithmic-corrected mass
Shinta Kasuya, Mayuko Taira
We consider a simple modification of quadratic chaotic inflation. We add a logarithmic correction to the mass term, and find that this model can be consistent with the latest cosmo…
Smallness of Baryon Asymmetry from Split Supersymmetry
Shinta Kasuya, Fuminobu Takahashi
The smallness of the baryon asymmetry in our universe is one of the greatest mysteries and may originate from some profound physics beyond the standard model. We investigate the Af…
Reheating as a surface effect
Kari Enqvist, Shinta Kasuya, Anupam Mazumdar
We describe a new mechanism for reheating the Universe through evaporation of a surface charge of a fragmented inflaton condensate. We show that for a range of Yukawa coupling of t…
Isocurvature fluctuations in Affleck-Dine mechanism and constraints on inflation models
Shinta Kasuya, Masahiro Kawasaki, Fuminobu Takahashi
We reconsider the Affleck-Dine mechanism for baryogenesis and show that the baryonic isocurvature fluctuations are generated in many inflation models in supergravity. The inflation…
Flavon Stabilization in Models with Discrete Flavor Symmetry
So Chigusa, Shinta Kasuya, Kazunori Nakayama
We propose a simple mechanism for stabilizing flavon fields with aligned vacuum structure in models with discrete flavor symmetry. The basic idea is that flavons are stabilized by…
Restriction to Parametric Resonant Decay after Inflation
Shinta Kasuya, Masahiro Kawasaki
We study parametric resonant decay of inflaton field with emphasis on its physical meaning. We show that the parametric resonance is indeed an induced process, which means that the…
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…
MeV gamma rays from Q-ball decay
Shinta Kasuya, Masahiro Kawasaki, Naomi Tsuji
We study the supersymmetric Q balls which decay at present and find that they create a distinctive spectrum of gamma rays at around O(10) MeV. The charge of the Q ball is lepton nu…
Enhancement of second-order gravitational waves at Q-ball decay
Shinta Kasuya, Masahiro Kawasaki, Kai Murai
The recent observation of He favors a large lepton asymmetry at the big bang nucleosynthesis. If Q-balls with a lepton charge decay after the electroweak phase transition, such…
Early reionization by decaying particles in the light of three year WMAP data
Shinta Kasuya, Masahiro Kawasaki
We study the reionization histories where ionizing UV photons are emitted from decaying particles, in addition to usual contributions from stars and quasars, taking account of the…
MSSM Higgses as the source of reheating and all matter
Kari Enqvist, Shinta Kasuya, Anupam Mazumdar
We consider the possibility that the dark energy responsible for inflation is deposited into extra dimensions outside of our observable universe. Reheating and all matter can then…
Throat effects on shadows of Kerr-like wormholes
Shinta Kasuya, Masataka Kobayashi
We revisit to investigate shadows cast by Kerr-like wormholes. The boundary of the shadow is determined by unstable circular photon orbits. We find that, in certain parameter regio…
Towards the robustness of Affleck-Dine mechanism
Shinta Kasuya
In this talk we considered the Affleck-Dine mechanism with various types of the Kahler potential, and investigate whether or not the Affleck-Dine field could acquire a large VEV as…
Axino dark matter and baryon number asymmetry production by the Q-ball decay in gauge mediation
Shinta Kasuya, Etsuko Kawakami, Masahiro Kawasaki
We investigate the Q-ball decay into the axino dark matter in the gauge-mediated supersymmetry breaking. In our scenario, the Q ball decays mainly into nucleons and partially into…
Towards the robustness of the Affleck-Dine baryogenesis
Shinta Kasuya, Masahiro Kawasaki
We study the Affleck-Dine mechanism with various types of the Kahler potential, and investigate whether or not the Affleck-Dine field could acquire a large VEV as an initial condit…
Baryogenesis from the Gauge-mediation type Q ball and the New type of Q ball as dark matter
Shinta Kasuya, Masahiro Kawasaki
We investigate that the two types of the Q balls explain the baryon asymmetry and the dark matter of the universe in the gauge-mediated supersymmetry breaking. The gauge-mediation…
On some hybrid-types of Q balls in the gauge-mediated supersymmetry breaking
Shinta Kasuya, Masahiro Kawasaki
We revisit the new-type of the Q ball (the gravity-mediation type of the Q ball in the gauge-mediation), in order to clarify its properties and correct some misunderstandings found…
Adiabatic density perturbations and matter generation from the MSSM
Kari Enqvist, Shinta Kasuya, Anupam Mazumdar
We propose that the inflaton is coupled to ordinary matter only gravitationally and that it decays into a completely hidden sector. In this scenario both baryonic and dark matter o…
Fate of thermal log type Q balls
Takeshi Chiba, Kohei Kamada, Shinta Kasuya +1
We study time evolution of the ball in thermal logarithmic potential using lattice simulations. As the temperature decreases due to the cosmic expansion, the thermal logarithmi…