ParisNN¯potential constrained by recent antiprotonic-atom data andn¯p<

Abstract

We report on an updated Paris NN optical potential. The long-and intermediate-range real parts are obtained by G-parity transformation of the Paris N N potential based on a theoretical dispersionrelation treatment of the correlated and uncorrelated two-pion exchange. The short-range imaginary potential parametrization results from the calculation of the NN annihilation box diagram into two mesons with a nucleon-antinucleon intermediate state in the crossed channel. The parametrized real and imaginary short range parts are determined by fitting not only the existing experimental data included in the 1999 version of the Paris NN potential, but also the recent antiprotonic-hydrogen data andnp total cross sections. The description of these new observables is improved. Only this readjusted potential generates an isospin zero 1 S0, 52 MeV broad quasibound state at 4.8 MeV below the threshold. Recent BES data on J/ψ decays could support the existence of such a state.

Status of X(1835) and pp¯ Interaction from Chiral Symmetry

“…Chiral NLO [26] −(306 · · · 361) (1528 · · · 1553) Chiral NNLO [26] −(302 · · · 361) (1545 · · · 1589) Jülich model D [48] −330 1380 Paris2009 [49] −778 1038 Grach et al…”

“…In Refs. [28,29], they do understand it as an isospin-0 1 S 0 bound state, located at E = −(4.8 − i26) MeV, predicted from the updated Paris 2009 potential [49], where the real part means that it stays below the threshold, and the imaginary part indicates the width Γ = 52 MeV. We also favor the interpretation as a bound state [13], but the binding energy can not be well determined since, in the model, the isospin average amplitude is taken and, in principle, any isospin combination is allowed.…”

A New Hadron Spectroscopy

“…An analysis based on an NN interaction derived in the framework of chiral effective field theory [17] finds an isovector NN bound state 37 MeV below the 2m p mass threshold [18]. In contrast, an analysis based on the Paris NN potential [19], attributes the threshold enhancement to the tail of an isospin singlet 1 S 0 NN state with a mass that is 4.8 MeV below threshold [20]. 2 This latter analysis also predicts a nearby triplet P-wave state.…”

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

“…Recently, the 2009 version of the ParisNN potential [3] was confronted by Friedman et al with thep-atom data and antinucleon interactions with nuclei up to 400 MeV/c, including elastic scattering and annihilation cross sections [8]. The analysis revealed the necessity to include the P-wave interaction in order to describe thep atom data.…”

“…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.…”