Nucleosynthesis in jets from a collapsar before the formation of a black hole

We have investigated nucleosynthesis inside the jets from a 35 M _⊙, low-metallicity collapsar before the formation of a black hole, based on a two-dimensional magneto-hydrodynamic (MHD) simulation of the collapsar, taking into account neutrino interactions both on the MHD simulation and nucleosynthesis. We find that jets are ejected via the magnetic pressure, and that r-process operates in the jets even if the neutrino absorption is taken into account in the nucleosynthesis calculation. This is due to efficient electron captures in the high-density (∼ 10¹¹ gcm^-3) region near the rotational axis, fast ejection (> 0.2 in units of speed of light), and relatively low neutrino luminosity (< 5 × 10 ⁵²ergss^-1). Chemical composition of the neutron-rich nuclei in jets from collapsars with different mass and rotation could be largely different from each other.