Near-threshold scaling of resonant inelastic collisions at ultralow temperatures

We show that the cross sections for a broad range of resonant inelastic processes accompanied by excitation exchange (such as spin exchange, F\"orster resonance, or angular momentum exchange) exhibit a near-threshold scaling {E}^{\mathrm{\ensuremath{\Delta}}{m}_{12}} where Eis the collision energy, \mathrm{\ensuremath{\Delta}}{m}_{12}={m}_{1}^{\ensuremath{'}}+{m}_{2}^{\ensuremath{'}}\ensuremath{-}{m}_{1}\ensuremath{-}{m}_{2} and...