Journal article

Publication year: 2022

Journal: Physical Review D

Volume number: 105

Issue number: 3

ISSN: 2470-0010

eISSN: 2470-0029

Open access status: Hybrid

DOI Link: https://doi.org/10.1103/PhysRevD.105.034025

Publisher: American Physical Society

Abstract: 
We study the dynamical generation of scalar mesons in the light quark sector (q is an element of {u, d, s}) and calculate the masses and widths for the f(0)(500), a(0)(980), and f(0)(980). To this end we study the mixing of conventional q (q) over bar and "exotic" q (q) over barq (q) over bar states via a coupled set of two-body Bethe-Salpeter equations based on a symmetry-preserving truncation of the underlying Dyson-Schwinger equations. This allows us to determine the dominant components of each state. Furthermore, we extend our previous framework into the complex energy plane such that we can study the analytic structure of the states in question and extract their width. At the physical point of small quark masses, the sigma meson is predominantly a pi pi resonance. Consequently, its mass and width is driven by the effects of chiral symmetry breaking. At larger quark masses, however, the conventional q (q) over bar components take over. Furthermore, we find a strong molecular K (K) over bar component for both, the strange-light f(0)(980) and the a(0)(980).

Harvard Citation style: Santowsky, N. and Fischer, C. (2022) Light scalars: Four-quark versus two-quark states in the complex energy plane from Bethe-Salpeter equations, Physical Review D, 105(3), Article 034025. https://doi.org/10.1103/PhysRevD.105.034025

APA Citation style: Santowsky, N., & Fischer, C. (2022). Light scalars: Four-quark versus two-quark states in the complex energy plane from Bethe-Salpeter equations. Physical Review D. 105(3), Article 034025. https://doi.org/10.1103/PhysRevD.105.034025