Work

Effective field theory of protonium

Year: 2026

Type: article

Abstract: We investigate the level shifts in protonium using the framework of non-relativistic effective field theory (NREFT). Our study is prompted by the PUMA collaboration’s plans to probe the neutron-to-proton ratio in the nuclear density tail using antiprotonic atoms – a method for which light atoms provide an important benchmark. We calculate the corrections to the Deser-Goldberger-Baumann-Thirring formula for the complex level shift of S-wave states from the unitary cusp and Coulomb photon exchange. Structure dependent corrections enter at the next order. For higher-partial-wave states, they enter already at leading order. Using input from chiral N N ¯ interactions, we compare to other calculations and measurements from LEAR.

Source: Physics Letters B

DOI: 10.1016/j.physletb.2026.141071

Authors: Hans-Werner Hammer, Akaki Rusetsky

Institutions: GSI Helmholtz Centre for Heavy Ion Research, Technische Universität Darmstadt, ExtreMe Matter Institute EMMI, University of Bonn

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: Deutsche Forschungsgemeinschaft, Bundesministerium für Bildung und Forschung, Ministerium für Kultur und Wissenschaft des Landes Nordrhein-Westfalen

Awards: G138487567, SFB 1245: Atomkerne: Von fundamentalen Wechselwirkungen zu Struktur und Sternen