Novel Feshbach resonances in a $^{40}$K spin-mixture

We present experimental results on novel s-wave Feshbach resonances in $^{40}$K spin-mixtures. Using an extended version of the Asymptotic Bound-state Model (ABM) [1] we predict Feshbach resonances with more promising characteristics than the commonly used resonances in the ($\vert $F,m$_{F}>) \quad \vert $9/2,-9/2$>+\vert $9/2,-7/2$>$ and $\vert $9/2,-9/2$>+\vert $9/2,-5/2$>$ spin mixtures. We report on an s-wave resonance in the $\vert $9/2,-5/2$>+\vert $9/2,-3/2$>$ mixture. We have experimentally observed the corresponding loss-feature at B$_{0}\sim $178 G with a width of $\sim $10G. This resonance is promising due to its large predicted width and the absence of an overlapping p-wave resonance. We present our recent results on measurements of the resonance width and the stability of the system around this and other observed s-wave and p-wave resonances. \\[4pt] [1] T.G. Tiecke, et al., Phys. Rev. Lett. 104, 053202 (2010).