Mixings of 4-quark components in light non-singlet scalar mesons in QCD sum rules

Sugiyama, J.; Nakamura, T.; Ishii, N.; Nishikawa, T.; Oka, M.

Mixings of 4-quark components in light non-singlet scalar mesons in QCD sum rules

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Description

Mixings of 4-quark components in the non-singlet scalar mesons are studied in the QCD sum rules. We propose a formulation to evaluate the cross correlators of q\bar q and qq\bar q \bar q operators and to define the mixings of different Fock states in the sum rule. It is applied to the non-singlet scalar mesons, a_0 and K_0^\ast. It is found that the 4-quark operators predict lower masses than the q\bar q operators and that the 4-quark states occupy about 70-90% of the lowest mass states.
8 pages, 9 figures