Frequency shifts of photoassociative spectra of ultracold metastable Helium atoms : a new measurement of the s-wave scattering length

J. Kim, S. Moal, M. Portier +3

We observe light-induced frequency shifts in one-color photoassociative spectra of magnetically trapped ${}^4$He${}^{\ast }$ atoms in the metastable $2^3{S}_1$ state. A pair of ultracold spin-…