quote:-
Earlier RHIC results suggested that when gold nuclei collide head-on their kinetic energy dissociates many nucleons and forms the hot,dense plasma of quarks and gluons,which must immediately begin to expand and cool.The hot plasma lasts only 10^-23 seconds,and only when the plasma cools sufficiently do the quarks and gluons "freeze out",leaving a spray of thousands of elementary particles carrying the signature of the hot,dense plasma that led to their production.
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Question, what is meant by "signature of the hot,dense plasma that led to their production"?