The Origin of Radio Emission in Black Hole X-ray Binaries
  We studied the relation of accretion-jet power and disk luminosity,
especially the jet efficiencies and disk radiative efficiencies for different
accretion disks as well as black hole (BH) spin, in order to explore the origin
of radio emission in black hole X-ray binaries (BHXBs). We found that jet
efficiency increases more rapidly (efficient) than the nearly constant disk
radiative efficiency for thin disk component in high accretion regime, which
could account for the steep track ($\mu>1$) in the observed radio and X-ray
luminosity relations ($L_{\rm R}\propto L_{\rm X}^{\mu}$), but the thin disk
component may not be able to explain the standard track ($\mu\approx 0.6$) in
the BHXBs. For hot accretion flows (HAF), the resulting jet efficiency changes
along with the large range of accretions from quiescent state to nearly
Eddington state, which could account for the standard track in the BHXBs. The
BH spin-jet is discussed for the magnetic arrested disk (MAD) state; in this
state, the spin-jet power might contribute to a linear correlation between jet
power and mass accretion rate for a given source. More accurate observations
are required to test the results.
