Reaction rate sensitivity of 44Ti production in massive stars and implications of a thick target yield measurement for 40Ca(alpha ,gamma )44Ti
Reaction rate sensitivity of 44Ti production in massive stars and implications of a thick target yield measurement for 40Ca(alpha ,gamma )44Ti
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大质量恒星中 44Ti 产生的反应速率敏感性以及 40Ca(alpha ,gamma )44Ti 厚目标产量测量的影响
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
D. Bleuel
中科院分区：
文献类型：
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作者：
R. Hoffman;S. Sheets;Jason T. Harke;N. Scielzo;T. Rauscher;E. Norman;S. Tumey;T. A. Brown;P. Grant;A. Hurst;L. Phair;M. Stoyer;T. Wooddy;J. Fisker;D. Bleuel
We evaluate two dominant nuclear reaction rates and their uncertainties that affect 44Ti production in explosive nucleosynthesis. Experimentally we develop thick target yields for the 40Ca(α, γ)44Ti reaction at E α = 4.13, 4.54, and 5.36 MeV using γ-ray spectroscopy. At the highest beam energy, we also performed an activation measurement which agrees with the thick target result. From the measured yields a stellar reaction rate was developed that is smaller than current statistical-model calculations and recent experimental results, which would suggest lower 44Ti production in scenarios for the α-rich freezeout. Special attention has been paid to assessing realistic uncertainties of stellar reaction rates produced from a combination of experimental and theoretical cross sections. With such methods, we also develop a re-evaluation of the 44Ti(α, p)47V reaction rate. Using these two rates we carry out a sensitivity survey of 44Ti synthesis in eight expansions representing peak temperature and density conditions drawn from a suite of recent supernova explosion models. Our results suggest that the current uncertainty in these two reaction rates could lead to as large an uncertainty in 44Ti synthesis as that produced by different treatments of stellar physics.
