Cosmology with Long-Lived Charged Massive Particles
  We investigate the evolution of the bound state of negatively charged massive
particles (CHAMPs) with light elements and discuss its cosmological
consequences and the constraint. By numerically solving the Boltzmann equation,
we study the time evolutions of such bound states. Since most of negative
CHAMPs are captured by He4, its bound state is positively charged and couples
with the electromagnetic plasma. When charged particles constitute a dominant
non-relativistic component, density fluctuations of matter cannot grow due to
the acoustic damping. This results in the suppression of matter power spectrum
from which a severe constraint can be obtained. By arguing constraints from
other aspects of cosmology, we show that the constraint from large scale
structure gives most stringent one in some representative cases.
