paper

Near-Maximal Mixing of Scalar Gluonium and Quark Mesons: A Gaussian Sum-Rule Analysis

arXiv:0804.2195 · doi:10.1016/j.nuclphysa.2010.12.005

Abstract

Gaussian QCD sum-rules are ideally suited to the study of mixed states of gluonium (glueballs) and quark () mesons because of their capability to resolve widely-separated states of comparable strength. The analysis of the Gaussian QCD sum-rules (GSRs) for all possible two-point correlation functions of gluonic and non-strange () quark scalar () currents is discussed. For the non-diagonal sum-rule of gluonic and currents we show that perturbative and gluon condensate contributions are chirally suppressed compared to non-perturbative effects of the quark condensate, mixed 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 two states with masses of approximately 1 GeV and 1.4 GeV that couple to significant mixtures of quark and gluonic currents. The mixing is nearly maximal with the heavier mixed state having a slightly larger coupling to gluonic currents than the lighter state.

Updated version contains extended analysis and revised analysis methods. 21 pages, 14 figures

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