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described in Ref. [20]. On carrying out the angular inte- grals we are left with a one-dimensional integral over the energy. As an example, we give the expression for the elementary loop 

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where θ is the Heaviside step function, x = ( p · q ) / | p || q | , and x ± 0 is the x value satisfying the equation ± ω + ϵ$_{p}$ − ϵ$_{p}$$_{+}$$_{q}$ = 0 and the prime refers to the scattering part. The expressions for the scattering parts of the polarization 

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tensors Π ′ XX ′ ( q ) are similar to Eq. (46), but involve dif- ferent combinations of coherence factors. The real parts are obtained from the dispersion relation (44). 

Figure 3 shows the real and imaginary parts of the scattering polarization tensor at two temperatures and for fixed momentum transfer. Figure 4 shows the spec- tral function derived from the scattering polarization ten- sor. It is seen that the modes with energies within the breaking threshold ω ≤ 2Δ(0) are relevant for scattering processes, as opposed to the pair breaking case where only the modes with ω ≥ 2Δ(0) emerge. This justifies the separation of the modes into two classes. The peak values are larger at higher temperatures T ≤ T$_{c}$ , as is the case for the pair breaking response. 

Here we wish to obtain the unpaired ( T > T$_{c}$ ) limit of the polarization function (18). This amounts to setting the coherence factors in Eq. (19)–(22) to their values in the normal state 

It follows then from Eq. (20) that Π$_{FG}$ = 0 = Π$_{GF}$ and, therefore, B = 0. Setting B = 0 in Eq. (18) and noting that C ̸ = 0, since Π$_{G}$ $^{†}$G ̸ = 0, we obtain 

## C. Unpaired and uncorrelated limits 

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