From glasma to quark-gluon plasma in heavy-ion collisions

When two sheets of color glass condensate collide in a high-energy heavy-ion collision, they form matter with very high energy densities called the glasma. We describe how this matter is formed, its remarkable properties and its relevance for understanding the thermalization of the quark-gluon plasma in heavy-ion collisions. Long-range rapidity correlations contained in the near-side ridge measured in heavy-ion collisions may allow one to directly infer the properties of the glasma.