  We report about a recent calculation of the heavy quarkonium mass and decay
width in a quark-gluon plasma, whose temperature T and screening mass m_D
satisfy the hierarchy m alpha_s >> pi T >> m alpha_s^2 >> m_D, m being the
heavy-quark mass, up to order m alpha_s^5. The calculation may be relevant to
understand the behavior of the Y(1S) in a quark-gluon plasma at present-day
colliders.
