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On the quark spectral function in QCD
by Jan Horak, Jan M. Pawlowski, Nicolas Wink
This Submission thread is now published as
Submission summary
| Authors (as registered SciPost users): | Jan Horak · Jan M. Pawlowski · Nicolas Wink |
| Submission information | |
|---|---|
| Preprint Link: | scipost_202307_00019v2 (pdf) |
| Date accepted: | 2023-09-06 |
| Date submitted: | 2023-08-02 03:03 |
| Submitted by: | Horak, Jan |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approaches: | Theoretical, Computational, Phenomenological |
Abstract
We calculate the spectral function of light quark flavours in 2+1 flavour vacuum QCD in the isospin-symmetric approximation. We employ spectral Dyson-Schwinger equations and compute the non-perturbative quark propagator directly in real-time, using recent spectral reconstruction results from Gaussian process regression of gluon propagator data in 2+1 flavour lattice QCD. Our results feature a pole-like peak structure at time-like momenta larger than the propagator's gapping scale as well as a negative scattering continuum, which we exploit assuming an analytic pole-tail split during the iterative solution. The computation is augmented with a general discussion of the impact of the quark-gluon vertex and the gluon propagator on the analytic structure of the quark propagator. In particular, we investigate under which conditions the quark propagator shows unphysical complex poles. Our results offer a wide range of applications, encompassing the ab-initio calculation of transport as well as resonance properties in QCD.
List of changes
- added a summary of the discussion of Appendix A below (9)
- added a comment that in contrast to other diagrammatic notations, in our notation full propagators do not carry blobs and the inverse bare propagator is simply given by a dot with two legs below Fig. 2
- added a subsentence mentioning the approximation (10) in the abstract
Published as SciPost Phys. 15, 149 (2023)
Reports on this Submission
Strengths
To the best of my understanding this is a relevant discussion of the analytic properties of the quark and gluon propagator. The authors have, in my opinion, taken the criticisms of the previous reviewing rounds on board, thereby improving the quality of the manuscript to a level where I am happy to support its publication.
Report
I think the criteria for publication are met - I support its speedy processing.
As the editor-in-charge found it difficult to recruit reviewers (an ongoing issue across the board and across journals that needs addressing), I was asked to look at the submission, without being an expert in the field. I therefore read the paper and reviewed its refereeing and submission history and found that the authors have by far and large met the criticisms of the better qualified referee, to a level where publication can be supported.