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Lepton asymmetry in the primordial gravitational wave spectrum
Kiyotomo Ichiki, Masahide Yamaguchi, Jun'Ichi Yokoyama
Effects of neutrino free streaming is evaluated on the primordial spectrum of gravitational radiation taking both neutrino chemical potential and masses into account. The former or…
Time variation of proton-electron mass ratio and fine structure constant with runaway dilaton
Takeshi Chiba, Tatsuo Kobayashi, Masahide Yamaguchi +1
Recent astrophysical observations indicate that the proton-electron mass ratio and the fine structure constant have gone through nontrivial time evolution. We discuss their time va…
Effects of Cosmic Strings on Free Streaming
Tomo Takahashi, Masahide Yamaguchi
We study the effect of free streaming in a universe with cosmic strings with time-varying tension as well as with constant tension. Although current cosmological observations sugge…
Implications of cosmic strings with time-varying tension on CMB and large scale structure
Kazuhide Ichikawa, Tomo Takahashi, Masahide Yamaguchi
We investigate cosmological evolution and implications of cosmic strings with time-dependent tension. We derive basic equations of time development of the correlation length and th…
Power Spectrum of the Density Perturbations From Smooth Hybrid New Inflation Model
Masahiro Kawasaki, Tsutomu Takayama, Masahide Yamaguchi +1
We numerically investigate density perturbations generated in the smooth hybrid new inflation model, a kind of double inflation model that is designed to reproduce the running spec…