Electromagnetic corrections toπNscattering

Abstract

Numerical results are presented for the electromagnetic corrections to the Sand P-wave phase shifts and inelasticities in 77 t p and .rr p scattering. A discussion is given of how to apply the corrections in practical data analysis.

Electromagnetic corrections for the analysis of low energy scattering data

“…In the sense of giving a reasonable averaging over an internally inconsistent body of data, the fit with the factor f included is certainly better than that where this factor is absent. In summary, we have given three pieces of evidence that favour the inclusion of the specific energy dependence introduced by the factor f in the hadronic potential term: the extrapolation of the invariant amplitudes to the Cheng-Dashen point, the comparison with the results of NORDITA [2] (who also include the mass differences) and the better fit to the data (judged not only by the value of χ 2 but also by the systematic deviation near 100 MeV when f is not included).…”

“…In the energy range T π ≤ 100 MeV these corrections are almost insignificant and it is sufficient to use the results of Ref. [2], which are derived from known amplitudes for the reactions γn → π − p, π 0 n using three-channel unitarity. It is unnecessary to introduce a complex hadronic potential matrix.…”

“…The corrections ∆T γn cc , ∆T γn 0c (for the s-and p 3/2 -waves) are related to the quantities η 1 , η 3 and η 13 in Table IV of Ref. [2] by the formulae…”

“…In Section 1 of Ref. [1] we gave our reasons for using such a potential model rather than the dispersion theory model of the NORDITA group [2,3]. Our aim in this paper is to describe the corresponding calculations for the two-channel (π − p, π 0 n) system in the same energy region.…”

Hadronic potentials from effective field theories

“…This problem is closely related to the problem of the hadronic bound states, which were discussed above. Two distinct approaches are available in the literature to address the issue in the scattering sector: the dispersion relations approach [11,12], and the potential scattering theory approach (see, e.g. [13][14][15]).…”