Work

Five-body systems with Bethe-Salpeter equations

Year: 2025

Type: article

Abstract: We extend the Bethe-Salpeter formalism to systems made of five valence particles. Restricting ourselves to two-body interactions, we derive the subtraction terms necessary to prevent overcounting. We solve the five-body Bethe-Salpeter equation numerically for a system of five scalar particles interacting by a scalar exchange boson. To make the calculations tractable, we implement properties of the permutation group S 5 and construct an approximation based on intermediate two- and three-body poles. We extract the five-body ground and excited states along with the spectra obtained from the two-, three-, and four-body equations. In the limit of a massless exchange particle, the two-, three, four- and five-body states coexist within a certain range of the coupling strength, whereas for heavier exchange particles the five-body system becomes Borromean. Our study serves as a building block for the calculation of pentaquark properties using functional methods.

Source: Physics Letters B

DOI: 10.1016/j.physletb.2025.139525

Authors: Gernot Eichmann, M.T. Peña, Raul D. Torres

Institutions: University of Graz, Nawi Graz, University of Lisbon, LIP - Laboratory of Instrumentation and Experimental Particle Physics, Instituto Superior Técnico

Language: English

Topic: Quantum Chromodynamics and Particle Interactions

Subfield: Nuclear and High Energy Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: diamond

Funders: Austrian Science Fund, Fundação para a Ciência e a Tecnologia

Awards: Pentaquark spectroscopy for the LHC, G4969885451, A estrutura dos multiquarks