Abstract
The soft wall model in holographic QCD has Regge trajectories but wrong operator product expansion (OPE) for the two-point vectorial QCD Green function. We modify the dilaton potential to comply with the OPE. We study also the axial two-point function using the same modified dilaton field and an additional scalar field to address chiral symmetry breaking. OPE is recovered adding a boundary term and low energy chiral parameters, F π and L 10 , are well described analytically by the model in terms of Regge spacing and QCD condensates. The model nicely supports and extends previous theoretical analyses advocating Digamma function to study QCD two-point functions in different momentum regions.
Highlights
This proceeding is based on our previous work [1]
One knows partially QCD Green functions on three ranges of energies (i) deep Euclidean, where perturbative QCD and operator product expansion (OPE) expansion methods can be applied, (ii) an intermediate Minkowski region, where resonances are described by Regge trajectories and (iii) the strong interacting, low-energy region, described by chiral perturbation theory [2]
In order to reproduce resonances masses with a Regge spacing, one can consider a 5D model with AdS metric and an additional field, the dilaton [18]. In this model it can be shown that the partonic log of the two point vectorial Green function receives /1 Q2-corrections differently from what holds in perturbative QCD Operator Product Expansion (OPE) [19,20,21,22]
Summary
This proceeding is based on our previous work [1]. As matter of fact, one knows partially QCD Green functions on three ranges of energies (i) deep Euclidean, where perturbative QCD and OPE expansion methods can be applied, (ii) an intermediate Minkowski region, where resonances are described by Regge trajectories and (iii) the strong interacting, low-energy region, described by chiral perturbation theory (χPT) [2]. A recent review of all these models and their relation with the light-front holographic QCD approach is Ref [15] All these models have a good description of the deep Euclidean region; for instance the correct two point function recover both the partonic log and a pretty well description of low energy QCD, obtaining values of the chiral parameters Fπ and the Gasser-Leutwyler coefficients Li’s which are close to the physical ones. In order to reproduce resonances masses with a Regge spacing, one can consider a 5D model with AdS metric and an additional field, the dilaton [18] In this model it can be shown that the partonic log of the two point vectorial Green function receives /1 Q2-corrections differently from what holds in perturbative QCD Operator Product Expansion (OPE) [19,20,21,22]. Beside being a novel proposal for holographic QCD, links naturally to previous 4D QCD work where a phenomenological matching between low energy and OPE was realised through Regge theory (or Veneziano model) [2, 5, 23,24,25,26,27]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
