Nucleosynthesis inside Magnetically-Driven Jets in A Gamma-Ray Burst

We investigate nucleosynthesis inside jets in a gamma ray bursts (GRB). We have calculated detailed composition of magnetically driven jets related to GRBs with post-processing calculation, which is based on long-term, magneto-hydrodynamic simulations of a rapidly rotating massive star of 40M _⊙ during core collapse. We follow abundance evolution of about 4000 nuclides inside the jets from the collapse phase to the ejection phase through the jet generation phase with a large nuclear reaction network. We find that the r-process successfully operates inside the jets, so that U and Th are synthesized abundantly. Abundance pattern inside the jets is similar compared to that of r-elements in the solar system. Heavy neutron-rich nuclei ∼ 0.001M_⊙ can be ejected through the jets. Furthermore, we find that p-nuclei are produced without seed nuclei: not only light p-nuclei, such as ⁷⁴Se, ⁷⁸Kr, ⁸⁴Sr, and ⁹²Mo, but also heavy p-nuclei, ¹¹³In, ¹¹⁵Sn, and ¹³⁸La, can be abundantly synthesized in the jets. The amounts of p-nuclei in the ejecta are much greater than those in core collapse supernovae (SNe). In particular, ⁹²Mo, ¹¹³In, ¹¹⁵Sn, and ¹³⁸La deficient in core collapse SNe, are significantly produced in the ejecta.