Extraction of ground-state decay constant from dispersive sum rules: QCD vs potential models

Autor(en)

Wolfgang Lucha, D Melikhov, Silvano Simula

Abstrakt

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(en)

Teilchenphysik

Externe Organisation(en)

Universität Wien, Università degli Studi di Roma La Sapienza

Journal

Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics

Band

687

Seiten

48-52

Anzahl der Seiten

5

ISSN

0370-2693

DOI

https://doi.org/10.1016/j.physletb.2010.02.080

Publikationsdatum

2010

Peer-reviewed

Ja

ÖFOS 2012

103036 Theoretische Physik

Link zum Portal

https://ucris.univie.ac.at/portal/de/publications/extraction-of-groundstate-decay-constant-from-dispersive-sum-rules-qcd-vs-potential-models(18415da7-43bd-49a5-b6dc-490cb33aabc6).html