Extraction of ground-state decay constant from dispersive sum rules: QCD vs potential models
- Author(s)
- Wolfgang Lucha, D Melikhov, Silvano Simula
- Abstract
We compare the extraction of the ground-state decay constant from the two-point correlator in QCD and in potential models and show that the results obtained at each step of the extraction procedure follow a very similar pattern. We prove that allowing for a Borel-parameter-dependent effective continuum threshold yields two essential improvements compared to employing a Borel-parameter-independent quantity: (i) It reduces considerably the (unphysical) dependence of the extracted bound-state mass and the decay constant on the Borel parameter. (ii) In a potential model, where the actual value of the decay constant is known from the Schrödinger equation, a Borel-parameter-dependent threshold leads to an improvement of the accuracy of the extraction procedure. Our findings suggest that in QCD a Borel-parameter-dependent threshold leads to a more reliable and accurate determination of bound-state characteristics by the method of sum rules.
- Organisation(s)
- Particle Physics
- External organisation(s)
- Sapienza University of Rome
- Journal
- Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics
- Volume
- 687
- Pages
- 48-52
- No. of pages
- 5
- ISSN
- 0370-2693
- DOI
- https://doi.org/10.1016/j.physletb.2010.02.080
- Publication date
- 2010
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103036 Theoretical physics
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/extraction-of-groundstate-decay-constant-from-dispersive-sum-rules-qcd-vs-potential-models(18415da7-43bd-49a5-b6dc-490cb33aabc6).html