Antinucleon-nucleon interaction at next-to-next-to-next-to-leading order in chiral effective field theory

Abstract

Abstract:Results for the antinucleon-nucleon (N N ) interaction obtained at next-to-nextto-next-to-leading order in chiral effective field theory (EFT) are reported. A new local regularization scheme is used for the pion-exchange contributions that has been recently suggested and applied in a pertinent study of the N N force within chiral EFT. Furthermore, an alternative strategy for estimating the uncertainty is utilized that no longer depends on a variation of the cutoffs. The low-energy constants associated with the arising contact terms are fixed by a fit to the phase shifts and inelasticities provided by a phase-shift analysis ofpp scattering data. An excellent description of theN N amplitudes is achieved at the highest order considered. Moreover, because of the quantitative reproduction of partial waves up to J = 3, there is also a nice agreement on the level ofpp observables. Specifically, total and integrated elastic and charge-exchange cross sections agree well with the results from the partial-wave analysis up to laboratory energies of 300 MeV, while differential cross sections and analyzing powers are described quantitatively up to 200-250 MeV. The low-energy structure of theN N amplitudes is also considered and compared to data from antiprotonic hydrogen.

Re-examining the X(4630) resonance in the reaction e+e−Dai1, Haidenbauer2, Meißner3 2017Phys. Rev. DSelf Cite411310View full textAdd to dashboardCite

“…The term(s) right after the equality sign represent the elastic part of the Λ þ cΛ − c interaction. The annihilation part is described likewise by contact terms but with a somewhat different form, in analogy to the treatment of NN annihilation in our chiral EFT potential [19,27]. We refer the reader to Sec.…”

“…For the cutoff mass Λ we consider a range similar to the one regarded in Ref. [27]. Specifically, we employ values between 0.45 GeV and 0.85 GeV.…”

“…In the actual construction of the Λ þ cΛ − c interaction we adopt chiral EFT [25,26] as guide line and follow closely the procedure that has been already utilized in the derivation of our NN interaction [19,27]. In this framework the potential is given in terms of pion exchanges and a series of contact interactions with an increasing number of derivatives.…”

“…Following Refs. [26,27] we do this by introducing a regulator function with a cutoff mass. Since the contact interactions are nonlocal, cf.…”

“…First of all, we explore in how far our results depend on the regularization procedure. For that we perform fits for a selection of cutoff masses between 0.45 and 0.85 GeV, so that we cover an even wider range as considered in the NN [26] and NN [27] studies. We perform also fits with a different number of contact terms in the…”