Kato, K.Wang, YujunKobayashi, J.Julienne, P. S.Inouye, S.2020-06-172020-06-172017-04-17https://hdl.handle.net/2097/40738Multichannel Efimov physics is investigated in ultracold heteronuclear admixtures of K and Rb atoms. We observe a shift in the scattering length where the first atom-dimer resonance appears in the 41K−87Rb system relative to the position of the previously observed atom-dimer resonance in the 40K−87Rb system. This shift is well explained by our calculations with a three-body model including van der Waals interactions, and, more importantly, multichannel spinor physics. With only minor differences in the atomic masses of the admixtures, the shift in the atom-dimer resonance positions can be cleanly ascribed to the isolated and overlapping Feshbach resonances in the 40K−87Rb and 41K−87Rb systems, respectively. Our study demonstrates the role of multichannel Feshbach physics in determining Efimov resonances in heteronuclear three-body systems.This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).https://rightsstatements.org/page/InC/1.0/?language=enhttps://journals.aps.org/authors/transfer-of-copyright-agreementAtomic & molecular collisionsInteratomic & molecular potentialsScattering of atoms, molecules, clusters & ionsScattering theoryText