Constraint on Lorentz symmetry breaking in Einstein-bumblebee theory by
  quasi-periodic oscillations
  We have studied quasi-periodic oscillations frequencies in a rotating black
hole in Einstein-bumblebee gravity by relativistic precession model. We find
that in the case with non-zero spin parameter both of the periastron and nodal
precession frequencies increase with the Lorentz symmetry breaking parameter,
but the azimuthal frequency decreases. In the non-rotating black hole case, the
nodal precession frequency disappears for arbitrary Lorentz symmetry breaking
parameter. With the observation data of GRO J1655-40, we constrain the
parameters of the rotating black hole in Einstein-bumblebee gravity, and find
that the Lorentz symmetry breaking parameter is almost negative in the range of
$1 \sigma$. The negative breaking parameter, comparing with the usual Kerr
black hole, leads to that the rotating black hole in Einstein-bumblebee gravity
owns the higher Hawking temperature and the stronger Hawking radiation, but the
lower possibility of exacting energy by Penrose process.
