  We study the influence of the in-medium mass difference between boson and
antiboson on their spectra. The in-medium mass difference may lead to a
difference between the transverse momentum spectra of boson and antiboson. This
effect increases with the increasing in-medium mass difference between boson
and antiboson. The difference between the transverse momentum spectra of boson
and antiboson increases with the increasing expanding velocity of the source
and decreases with the increasing transverse momentum in large transverse mass
region (mT > 1:6 GeV)
