Journalartikel

Jahr der Veröffentlichung: 2020

Zeitschrift: Physical Review D

Bandnummer: 102

Heftnummer: 5

ISSN: 1550-7998

eISSN: 1550-2368

Open Access Status: Hybrid

DOI Link: https://doi.org/10.1103/PhysRevD.102.056014

Verlag: American Physical Society

Abstract: 
We study the dynamical generation of resonances in isospin singlet channels with mixing between two-and four-quark states. To this end, we generalize a Bethe-Salpeter approach to four-quark states employed previously to accommodate for mixing diagrams. The q (q) over barq (q) over bar and q (q) over bar components of the Bethe-Salpeter wave function (with light quarks q is an element of {u, d}) are determined consistently in a symmetry-preserving truncation of the underlying Dyson-Schwinger equations. As a prominent example, we deal with the isospin-singlet 0(++) meson with light quark content. We find that the pi pi contribution of the four-quark component is mainly responsible for the low (real part of the) mass of the resulting state. We also study the analytic structure in the complex momentum plane and find a branch cut at the two-pion threshold and a singularity in the second Riemann sheet indicating a considerable decay width. Our findings are in excellent qualitative agreement with the general picture for the sigma/f(0)(500) that emerged in the past two decades from dispersive approaches.

Harvard-Zitierstil: Santowsky, N., Eichmann, G., Fischer, C., Wallbott, P. and Williams, R. (2020) σ-meson: Four-quark versus two-quark components and decay width in a Bethe-Salpeter approach, Physical Review D, 102(5), Article 056014. https://doi.org/10.1103/PhysRevD.102.056014

APA-Zitierstil: Santowsky, N., Eichmann, G., Fischer, C., Wallbott, P., & Williams, R. (2020). σ-meson: Four-quark versus two-quark components and decay width in a Bethe-Salpeter approach. Physical Review D. 102(5), Article 056014. https://doi.org/10.1103/PhysRevD.102.056014