Rational: for the reconstruction of resolved resonances, a number of auxiliary functions have to be defined. These functions are the penetrability P, the shift factor S and the phase shift phi. These functions are dependent on the reaction channel to which they are assigned as well as the quantum number of l of the incoming wave. For neutrons, the common representation for these functions are rational polynomial functions for l values larger than zero (for l=0, these functions are constant). For example:
P0 = x
P1 = x^3 / 1 + x^2
P2 = x^5 / 9 + 3x^2 + x^4
For photons, they are essentially constants and for charged particles, these functions depend heavily upon the Coulomb wave functions. In this last case, they cannot be represented by a rational polynomial function.
I would also like to note that in the proposal for the resonance region, the evaluator will have the possibility to specify these functions for every value of the quantum number l and channel in the resonance parameters.
Rational: for the reconstruction of resolved resonances, a number of auxiliary functions have to be defined. These functions are the penetrability P, the shift factor S and the phase shift phi. These functions are dependent on the reaction channel to which they are assigned as well as the quantum number of l of the incoming wave. For neutrons, the common representation for these functions are rational polynomial functions for l values larger than zero (for l=0, these functions are constant). For example:
For photons, they are essentially constants and for charged particles, these functions depend heavily upon the Coulomb wave functions. In this last case, they cannot be represented by a rational polynomial function.
I would also like to note that in the proposal for the resonance region, the evaluator will have the possibility to specify these functions for every value of the quantum number l and channel in the resonance parameters.