Near-Maximal Mixing of Scalar Gluonium and Quark Mesons: A Gaussian Sum-Rule Analysis
نویسنده
چکیده
Gaussian QCD sum-rules are ideally suited to the study of mixed states of gluonium (glueballs) and quark (qq̄) mesons because of their capability to resolve widely-separated states of comparable strength. The Gaussian QCD sum-rules (GSRs) for all possible two-point correlation functions of gluonic and non-strange I = 0 quark scalar (J = 0) currents are calculated and analyzed. For the non-diagonal sum-rule of gluonic and qq̄ currents we show that perturbative contributions are chirally-suppressed compared to non-perturbative effects of the quark condensate and instantons, implying that the mixing of quark mesons and gluonium is of non-perturbative origin. The independent predictions of the masses and relative coupling strengths from the non-diagonal and the two diagonal GSRs are remarkably consistent with a scenario of strongly-mixed states with masses of approximately 1 GeV and 1.4 GeV. The mixing is nearly maximal with the heavier mixed state having a slightly larger gluonium content than the lighter state.
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Gaussian Sum-Rule Analysis of Scalar Gluonium and Quark Mesons
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