Loss features in ultracold ¹⁶²Dy gases: Two- versus three-body processes

Dipolar gases like erbium and dysprosium have a dense spectrum of resonant loss features associated with their strong anisotropic interaction potential. These resonances display various behaviors with density and temperature, implying diverse microscopic properties. Here we quantitatively investigate the low -field (B < 6 G) loss features in ultracold thermal samples of Dy-162. The atoms are spin polarized in their lowest internal state so that pure two -body losses due to spin relaxation are forbidden. However, our analysis reveals that some resonances lead to a two -body -like decay law, while others show the expected three -body decay. We present microscopic one-step and two-step models for these losses, investigate their temperature dependence, and detect a feature compatible with a d -wave Fano-Feshbach resonance that has not been observed before. We also report the variation of the scattering length around these resonances, inferred from the time -of -flight expansion of the condensate.