15,612 research outputs found
Thermal Timescale Mass Transfer Rates in Intermediate-Mass X-ray Binaries
Thermal timescale mass transfer generally occurs in close binaries where the
donor star is more massive than the accreting star. The mass transfer rates are
usually estimated in terms of the Kelvin-Helmholtz timescale of the donor star.
But recent investigations indicate that this method may overestimate the real
mass transfer rates in accreting white dwarf or neutron star binary systems. We
have systematically investigated the thermal-timescale mass transfer processes
in intermediate-mass X-ray binaries, by calculating binary evolution sequences
with various initial donor masses and orbital periods. From the calculated
results we find that on average the mass transfer rates are lower than
traditional estimates by a factor of .Comment: 13 pages, 4 figures, and 2 tables, accepted for publication in A&
U-spin analysis of CP violation in decays into three charged light pseudoscalar mesons
We carry out a -spin symmetry analysis for CP violation in decays
into three light , , and mesons. We clarify some subtle points in constructing decay
amplitudes with formed by the two negatively charged light mesons in the
final states. -spin conserving momentum independent and momentum dependent
decay amplitudes, and -spin violating decay amplitudes due to quark mass
difference are constructed.Comment: RevTex 12 pages wit no figur
The signature of the scattering between dark sectors in large scale cosmic microwave background anisotropies
We study the interaction between dark sectors by considering the momentum
transfer caused by the dark matter scattering elastically within the dark
energy fluid. Describing the dark scattering analogy to the Thomson scattering
which couples baryons and photons, we examine the impact of the dark scattering
in CMB observations. Performing global fitting with the latest observational
data, we find that for a dark energy equation of state , the CMB gives
tight constraints on dark matter-dark energy elastic scattering. Assuming a
dark matter particle of proton mass, we derive an elastic scattering cross
section of where is the
cross section of Thomson scattering. For , however, the constraints are
poor. For , can formally take any value.Comment: 9 pages, 6 figures, accepted for publication in PR
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