Toward twist-2 T-odd transverse-momentum-dependent gluon distributions: the f-type linearity function

We present preliminary results on the leading-twist transverse-momentum-dependent (TMD) gluon linearity function, which is directly connected to nucleon transverse-spin asymmetries originating from the density of linearly-polarized gluons. The function is calculated in a spectator-model framework for the parent proton and for the $f$-type gauge-link structure. Our work represents a further step toward the definition of a complete set of gluon TMD distributions at twist-2 that can be used to access the gluon dynamics inside nucleons and nuclei at new-generation colliders.