Speaker
Description
Chiral effective field theory (chiral EFT) provides a systematic framework for understanding the long-range forces between hadrons based on QCD. Recent advances in femtoscopic measurements 1 have expanded experimental access to hadron–hadron interactions beyond the nucleon–nucleon system, while lattice QCD has provided quantitative results for heavy-quarkonium–nucleon interactions at a near-physical pion mass 2. Since heavy quarkonia are isoscalar, one-pion exchange is absent, and two-pion exchange provides the leading long-range force. In standard chiral power counting, the leading two-pion-exchange contribution appears at N3LO, whereas the contribution involving the low-energy constant ($c_3$), known to be sizable in the nucleon–nucleon force because of the ($\Delta(1232)$) resonance, first appears at N4LO 3. We evaluate this N4LO contribution and find that it exceeds the N3LO one in the distance range of interest. Furthermore, including the N4LO contribution with the quarkonium chromo-polarizability ($\beta$) as the only fit parameter significantly improves agreement with the lattice QCD potential.
References
1 L. Fabbietti et al., Annu. Rev. Nucl. Part. Sci. 71, 377 (2021)
2 Y. Lyu et al., Phys. Lett. B 860, 139178 (2025)
3 J. Tarrús Castellà and G. Krein, Effective field theory for the nucleon-quarkonium interaction, Phys. Rev. D 98, 014029 (2018).