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Someone (T.D.Lee?) said that quark-gluon plasma would (after 1980?) be very important to understand high-energy physics experiments.

I read some description of this new state in wikipedia (Quark–gluon plasma). I wonder what are the new progresses of this field and how we treat (physics and mathematic aspects) it. And, what we need to know about this new state, e.g., how they interact?

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closed as not a real question by John Rennie, Waffle's Crazy Peanut, David Z Feb 7 '13 at 18:17

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.

Hi hsxie, and welcome to Physics Stack Exchange! This question is too broad to really be appropriate here; the site is for specific conceptual physics questions. If you can edit it to be more specific about what you would like to know about the QGP, it can certainly be reopened. –  David Z Feb 7 '13 at 18:18

1 Answer 1

The quark gluon plasma is explored at LHC with the ion experiments there. A description can be found here.

In heavy-ion collisions, the first evidence for jets was seen in 2003 in the STAR and PHENIX experiments at Brookhaven National Laboratory’s Relativistic Heavy Ion Collider (RHIC) in the US. These jets showed a remarkable difference from those in simpler collisions, however. In the most striking measurement, STAR observed that one of the two back-to-back jets was invariably “quenched,” sometimes weakened and sometimes completely extinguished. The further a jet has to push through the dense fireball of a heavy-ion collision – 30 to 50 times as dense as an ordinary nucleus – the more energy it loses.

Jets are “hard probes”, by nature strongly interacting but moving so fast and with so much energy that they are often not completely absorbed by the surrounding quarks and gluons in the quark-gluon plasma. The degree of jet quenching – a figure that emerges in data from millions of collision events – plus the jets' orientation, directionality, composition, and how they transfer energy and momentum to the medium, reveal what’s inside the fireball and thus the properties of the quark-gluon plasma.

Recently the ALICE, ATLAS and CMS experiments at CERN’s Large Hadron Collider (LHC) have confirmed the phenomenon of jet quenching in heavy-ion collisions. The much greater collision energies at the LHC push measurements to much higher jet energies than are accessible at RHIC, allowing new and more detailed characterization of the quark-gluon plasma. Theoretical understanding of these measurements is challenging, however, and is one of the most important problems in quantum chromodynamics today.

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"Theoretical understanding of these measurements is challenging, however, and is one of the most important problems in quantum chromodynamics today." So, it is still a new challenging field. I understand now. –  hsxie Feb 7 '13 at 18:08

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