title: Efimov Resonance and Three-Body Parameter in a Lithium-Rubidium Mixture.
abstract: We study collisional heating in a cold ^{7}Li-^{87}Rb mixture near a broad Feshbach resonance at 661 G. At the high field slope of the resonance, we find an enhanced three-body recombination rate that we interpret as a heteronuclear Efimov resonance. With improved Feshbach spectroscopy of two further resonances, a model for the molecular potentials has been developed that now consistently explains all known Feshbach resonances of the various Li-Rb isotope mixtures. The model is used to determine the scattering length of the observed Efimov state. Its value of -1870a_{0} Bohr radii supports the currently discussed assumption of universality of the three-body parameter also in heteronuclear mixtures.
authors.affiliation: Physikalisches Institut, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen, Germany.
authors.forename: R A W
authors.initials: RA
authors.lastname: Maier
authors.affiliation: Physikalisches Institut, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Eisele
authors.affiliation: Institut für Quantenoptik, Leibniz Universität Hannover, Welfengarten 1, D-30167 Hannover, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Tiemann
authors.affiliation: Physikalisches Institut, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Zimmermann