Energy-dependent partial-wave analysis of all antiproton-proton scattering data below 925 MeV/c

Abstract

We present a new energy-dependent partial-wave analysis of all antiproton-proton elastic (pp → pp) and charge-exchange (pp → nn) scattering data below 925 MeV/c antiproton laboratory momentum. The long-range parts of the chiral one-and two-pion exchange interactions are included exactly. The short-range interactions, including the coupling to the mesonic annihilation channels, are parametrized by a complex boundary condition at a radius of r = 1.2 fm. The updated database, which includes significantly more high-quality charge-exchange data, contains 3749 scattering data. The fit results in χ 2 min /N df = 1.048, where N df = 3578 is the number of degrees of freedom. We discuss the description of the experimental data and we present the antiproton-proton phase-shift parameters.

The electromagnetic form factors of the proton in the timelike region

“…In that reference,NN potentials up to next-to-next-to-leading order (NNLO) were constructed, based on a modified Weinberg power counting, in close analogy to pertinent studies of the nucleonnucleon interaction [51]. The low-energy constants associated with the arising contact interactions are fixed by a fit to phase shifts and inelasticities provided by a recently published phase-shift analysis ofpp scattering data [36]. In the 3 S 1 -3 D 1 partial wave that is needed for the study of the reactionpp ↔ e + e − good overall agreement with the antinucleon-nucleon phase shifts and inelasticities was obtained up to laboratory energies of around 200 MeV [37].…”

“…The study is based on the one-photon approximation for the elementary reaction mechanism, but takes into account rigorously the effects of thepp interaction. For the latter we utilized a recently publishedNN potential derived within chiral effective field theory [37] and fitted to results of a new partial-wave analysis ofpp scattering data [36], and also one of the phenomenologicalNN meson-exchange models constructed by the Jülich group [21].…”

“…Furthermore, it enables us to obtain non-trivial results for angular distributions and compare those to available data, and we can make concrete predictions for (not yet measured) spin-dependent observables. Finally, in the meantime results of a new partial-wave analysis (PWA) ofpp scattering data have been published [36]. Based on that work anNN potential has been constructed by us [37], in the framework of chiral effective field theory (EFT), that reproduces the amplitudes determined in the PWA very well up to laboratory energies of T lab ≈ 200 − 250 MeV.…”

“…For the potential V in Eq. (9) we utilize a recently published interaction derived within chiral EFT [37] and fitted to results of a new PWA ofpp scattering data [36], and one of the phenomenologicalNN models constructed by the Jülich group [21]. In the above equations…”

Antiproton–nucleus quasi-bound states within the 2009 version of the Paris N̅ N potential

“…However, it is desirable to study thep interactions with the nuclear medium within other theoretical approaches, such as microscopic models ofNN interaction based on mesonexchange models [3][4][5] or chiralNN interaction models [6,7]. Comparison between thesē NN interaction models could bring valuable information about in-mediump interactions in the direct confrontation with the data fromp atoms andp scattering off nuclei, as well as predictions forp-nuclear quasi-bound states.…”