Relativistic three-body approach to NN scattering at intermediate energies

Abstract

The Bethe-Salpeter equation for coupled-channel N-b scattering is extended to satisfy unitarity in the NN and NN~sectors. The procedure eliminates the unitarity violations characteristic of the standard ladder Bethe-Salpeter equation in the inelastic region, and improves the description of pion production near threshold. Results are presented for the NN phase shifts and a number of observables up to 1 GeV. In particular, the D2 inelasticity is found to be considerably smaller than found from phase shift analysis. In this context, the importance of the pion deuteron channel for the inelasticity parameter is pointed out.

Erratum: Feynman-Schwinger representation approach to nonperturbative physics [Phys. Rev. C60, 055210 (1999)]

“…[9] in the case of SQED in 2+1 dimension. The perturbative result develops a complex mass beyond a critical coupling The occurrence of complex ghost poles in the propagator has also been found in Lee-like models [10,11] and in π − N-interaction models [12]. Moreover, it is also interesting to note that a similar critical behaviour was also observed within the context of one body DysonSchwinger equation in Ref.…”

Modelling nucleon-nucleon scattering above 1 GeV

“…(11), to determine the NN T -matrix, from which phase parameters and observables can be calculated. It is wellknown that models of this kind [27,28,30,55] are able to describe NN scattering up to about 1 GeV in semi-quantitative terms. Using the parameters listed in Table I, phase shifts and inelasticity parameters are predicted as shown in Fig.…”

“…The 'standard model' for the nuclear force is relativistic meson-exchange. In the past, meson models have been constructed and shown to describe NN scattering up to about 1 GeV satisfactorily [9,[23][24][25][26][27][28][29][30][31][32]]. …”

Toy model for pion production in nucleon-nucleon collisions. II. The role of three-particle singularities

“…[14][15][16]). In the context of NN potentials that incorporate pion production explicitly, the breakup has been treated either by complex contour deformation [17], spline methods [18], or subtraction methods [19,20]. For the explicit calculation of pion production observables the last seem preferable, since all calculations are carried out along the real axis.…”

“…In summary, with the above algebraic transformations, the second term in Eq. (3.12) is expressed as 19) where the integration interval R no was defined in Eq. (3.14).…”