ParisNN¯potential and recent proton-antiproton low energy data

Abstract

The inner part of the Paris nucleon-antinucleon optical potential has been reanalyzed in view of new experimental constraints. These are mainly provided by accurate measurements of the analyzing power in charge-exchange scattering, pp~n n, together with elastic pp -+ pp polarization data, allowing a better determination of the isospin dependence of the short-range forces. The 6t is performed with a set of 3632 data. The good quality of the St is illustrated over a large sample of observables for laboratory momenta from 180 to 910 MeV/c. Curves of the potentials and of the phase shifts are shown as well as the parameters of the potentials and effective range formula coefBcients for the S and P waves. The spectrum of resonances and bound states predicted by our potential is also displayed. In particular, a bound state having the AX(1565) quantum numbers is found with the right mass.PACS number(s): 13.75.Cs, 21.30. +y

Constraints on interaction from the process near threshold

“…[1][2][3][4][5][6] and recent reviews [7,8]. However, parameters of the models still can not be extracted with a good accuracy from the experimental data [9].…”

“…Such strong dependence at small (E − M )/M is related to the interaction of proton and antiproton at large distances r >> 1/M . Therefore, it is possible to take one of the nucleon-antinucleon interactions determined in [1][2][3][4][5][6] for describing the final state interaction (FSI) in the process e + e − → pp in order to explain the experimental data. In the present paper, we use the Paris nucleon-antinucleon optical potential V NN which has the form [4,5]:…”

Systematic effects in the determination of the πNN coupling from differential cross section

“…Such a study is most readily done using a model which represents the main physics even if it only qualitatively reproduces the data. The Paris antiproton model is sufficient for this purpose and readily reproducible [17]. The characteristic shape and magnitude of the terms in eq.…”

“…Note the similar quality of the descriptions. [17] and for PS206 [10] at 176 MeV for n=3, 4 and 5. Note that n = 4 or 5 is required by the data.…”

“…For this we generate 10.000 equivalent pseudo experiments which we analyze in the same way as the actual experiment. As models we use a solution of a preliminary analysis of the Nijmegen group [18] and the Paris potential prediction [17]. However any other model with known pion exchange would do as well for the present purpose if it approximately reproduces the data.…”