A session on results from the LHC at last week’s AAAS meeting has generated some news reports about results from the heavy ion run, see here and here. Under the heading “String theory supported”, MSNBC reports:
Previous experiments conducted at another particle accelerator, the Relativistic Heavy-Ion Collider in New York, showed that quark-gluon plasma took on the form of a liquid. Some scientists expected the plasma to go to a gaseous state at the higher temperatures achieved by ALICE, but it didn’t. Instead, it was a “perfect liquid, which flows without resistance and is completely opaque,” Schutz said.
That in itself was a big surprise. But Schutz told me that the results were consistent with what had been predicted by a particular variant of string theory known as AdS/CFT correspondence, which also addresses such mysteries as quantum gravity and extra dimensions. “I’m surprised that they can make a prediction and that it matches what we measured,” Schutz said.
String theory is a long-debated conception of the subatomic world that envisions matter as being composed of incredibly tiny strings or membranes that vibrate in an 11-dimensional universe. Skeptics have criticized the concept as being untestable and unfalsifiable, but if findings from the LHC can confirm some hypotheses and falsify others, that could increase string theory’s acceptance.
The campaign to deal with the failure of string theory unification by confusing it with AdS/CFT as an approximate calculational method continues. No matter how successful or unsuccessful AdS/CFT is at describing heavy-ion collisions, this has nothing to do with string theory as a unified theory of gravity and the Standard Model. I am curious though about the question of how well AdS/CFT does work as an approximation for describing heavy-ion physics. Can anyone point me to distinctive AdS/CFT predictions about what the LHC should see that are now being tested? The news reports just seem to refer to evidence that at LHC energies the quark-gluon plasma seems to continue to exhibit the perfect liquid behavior seen at RHIC.
Update: See the comment section for an extensive discussion by someone expert in the field (Hans Juergen Pirner) relevant to the question I was raising.