Chiral Loops and Ghost States in the Quenched Scalar Propagator
The scalar, isovector meson propagator is analyzed in quenched QCD, using the MQA pole-shifting ansatz to study the chiral limit. In addition to the expected short-range exponential falloff characteristic of a heavy scalar meson, the propagator also exhibits a longer-range, negative metric contribution which becomes pronounced for smaller quark masses. We show that this is a quenched chiral loop effect associated with the anomalous structure of the eta' propagator in quenched QCD. Both the time dependence and the quark mass dependence of this effect are well-described by a chiral loop diagram corresponding to an eta'-pi intermediate state, which is light and effectively of negative norm in the quenched approximation. The relevant parameters of the effective Lagrangian describing the scalar sector of the quenched theory are determined.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research (ER) (US)
- DOE Contract Number:
- AC05-84ER40150
- OSTI ID:
- 787760
- Report Number(s):
- JLAB-THY-01-30; DOE/ER/40150-1918; hep-lat/0106008; FERMILAB-Pub-01/129-T; TRN: US0200929
- Journal Information:
- Phys. Rev. D 65, 014509 (2002), Other Information: No journal information given for this preprint; PBD: 1 Jun 2001; PBD: 1 Jun 2001
- Country of Publication:
- United States
- Language:
- English
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