To find convincing evidence for a QGP phase transition in heavy-ion collisions has appeared to be difficult. Quarks and gluons coexisting in the QGP state cannot be measured directly, and a lot of information from the early stages of the collision may get lost when the system hadronizes. The various kinds of measurements suggested probably have to be combined to get a more reliable proof of the formation of a QGP. A description of the ideas behind some of the most promising signatures is given below.
Suppression