We consider along this section that the uncoupled unitarity relation of Eq. (13.5) can be applied, at least in good approximation, and assume that the strong interacting PWA is known.

1. 1.

   If there is a difference between these two phases of\(\pi \) then just take\(-F(s)\).

2. 2.

   Later we discuss a specific situation when this is not the case.

3. 3.

   In nonrelativistic scattering we know from the Levinson theorem [17, 80] that\(\delta (0)-\delta (\infty )=(n+q/2)\pi \), wheren is the number of bound states in the problem andq only applies toS-wave\((\ell =0)\), being the number of zero energyS-wave resonances. For the precise condition of this later case consider Eq. (95) of Ref. [17].

4. 4.

   Maybe some readers are used to consider that the form factors should only have RHC. Here we use the notation introduced in Chap. 13.

Authors and Affiliations

1. Departamento de Física, Universidad de Murcia, Murcia, Spain

   José Antonio Oller

Corresponding author

Correspondence toJosé Antonio Oller.

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