Efimovian three-body potential from broad to narrow Feshbach resonances

We analyse the change in hyperradial Efimovian three-body potential as two-body interaction is tuned from broad to narrow Feshbach resonance regime. Here, it known both theory and experiment that dissociation scattering length $a_-$ shifts away universal value of $-9.7 \ r_{\mathrm{vdW}}$, with $r_{\mathrm{vdW}} = \frac{1}{2} \left(m C_6/\hbar^2 \right)^{1/4}$ van der Waals range. model system using a separable takes into account full zero-energy behaviour multichannel wave function. find short-range repulsive barrier characteristic for single-channel models remains resonances, whilst parameter originates strong decrease depth. From an analysis underlying spin structure we further attribute this behavior dominance resonant channel compared other background interactions.