Pinpointing Feshbach Resonances and Testing Efimov Universalities in $^{39}$K

Understand

Using a combination of bound-state spectroscopy and loss spectroscopy, we pinpoint eight intrastate Feshbach resonances in $^{39}$K, as well as six previously unexplored interstate ones.

• We also perform a detailed characterization of four of the intrastate resonances and two of the interstate ones.
• We carry out coupled-channel scattering calculations and find good agreement with experiment.
• The combination of experiment and theory provides a faithful map of the scattering length $a$ and permits precision measurements of the signatures of Efimov physics across four intermediate-strength resonances.