Darmstadt 2008 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 21: Theorie

HK 21.2: Talk

Tuesday, March 11, 2008, 09:00–09:15, 2F

Holographic glueball structure — •Hilmar Forkel — ITA, Sao Paulo, Brazil — Institut fuer Theoretische Physik, Uni Heidelberg

We derive and systematically analyze the scalar glueball correlation functions in both the hard-wall and dilaton soft-wall approximations to holographic QCD. We find the nonperturbative physics described by the hard- and soft-wall correlators to be largely complementary. A detailed comparison with QCD results then allows us to obtain holographic estimates for the three lowest-dimensional gluon condensates, the two leading moments of the instanton size distribution in the QCD vacuum, and an effective UV gluon mass. We further obtain the first holographic estimates for the decay constants of the scalar glueball and its excitations. The hard-wall background turns out to encode more of the relevant QCD physics, and its prediction f = 0.8 - 0.9 GeV for the phenomenologically important ground state decay constant agrees inside errors with recent QCD sum rule and lattice results.