T-even transverse momentum dependent gluon fragmentation functions in a spectator model

We present a model calculation of transverse momentum dependent (TMD) gluon fragmentation functions for the spin-1/2 and spin-0 hadrons. The model is based on the assumption that a time-like off-shell gluon can fragments into a hadron and a single spectator particle. So far such spectator models have only been used to calculate the TMD distribution functions of quark and gluons. The gluon-hadron-spectator coupling is described by an effective vertex containing two form factors. We obtain the analytic expressions for the four T-even TMD fragmentation functions of the gluon. We also present the numerical results for the $z$-dependence and $k_T$-dependence of the fragmentation functions. Our study shows that the effects of these fragmentation functions may be significant and could be probed by future experimental measurements.