4 papers
Kaon Portal to Freeze-in Dark Matter
Motoi Endo, Takumu Yamanaka
We investigate freeze-in production of light dark matter through the quark flavor-changing operator in a low-reheating cosmology. For reheating temperatu…
Sommerfeld enhancement from unstable final-state particles in dark matter annihilation
Tomohiro Abe, Ryosuke Sato, Takumu Yamanaka
We study the Sommerfeld enhancement of the annihilation cross section of dark matter into heavier unstable particles. In this process, the annihilation products become non-relativi…
Excluding MeV-scale QCD axions by at KTeV
Takaya Iwai, Ryosuke Sato, Kohsaku Tobioka +1
An interesting proposal suggests that a QCD axion coupling to the up quark, down quark, and electron remains viable for an axion mass near 10~MeV. In this paper, this possibi…
Composite Dark Matter with Forbidden Annihilation
Tomohiro Abe, Ryosuke Sato, Takumu Yamanaka
A dark matter model based on QCD-like gauge theory with electroweakly interacting dark quarks is discussed. Assuming the dark quark mass is smaller than the dynamical…