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arXiv 1808.03249hep-phastro-ph.SRnucl-th
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核心坍缩超新星中中微子诱导的反应:对电子分数的影响

Neutrino induced reactions in core-collapse supernovae: effects on the electron fraction

M. M. Saez, O. Civitarese, M. E. Mosquera

摘要:

中微子引发的反应是恒星演化等天体物理过程的基本组成部分。中微子振荡的存在会影响核电弱衰变的速率,而核电弱衰变参与了决定恒星命运的事件链。在感兴趣的过程中,核心坍缩超新星中重元素的产生强烈依赖于中微子性质,例如不同种类中微子之间的混合。在这项工作中,我们研究了中微子振荡对电子分数作为中微子混合参数的函数的影响,两个计划:$1+1$计划(一个活动中微子和一个无菌中微子)和$2+1$计划(两个活动中微子和一个无菌中微子)。我们已经进行了这种分析,考虑核心坍缩超新星,并确定所需的物理条件,以激活核反应链参与r-过程。我们发现中微子与物质的相互作用以及它们之间的相互作用以及中微子球中初始的无菌中微子数量可能会改变电子分数,从而影响r过程的开始。我们已经设置了约束的活性-无菌中微子混合参数。它们是质量差平方$Δm^2_{14} $、混合角$\sin^2 2θ_{14}$和惰性中微子占据的阻碍因子$ξ_s $。计算已进行了不同值的$X_α$,这是部分的$α$ -粒子。对于$X_α=0$,如果是$Δm^2_{14} \geq 2 \, {\rm eV}^2 $、$\sin^2 2θ_{14} < 0.8 $和$ξ_s < 0.5$,则发生r过程。对于较大的$X_α$值,参数的区域大大减小。目前的结果进行了比较,在文献中的结果。

英文摘要:

Neutrino induced reactions are a basic ingredient in astrophysical processes like star evolution. The existence of neutrino oscillations affects the rate of nuclear electroweak decays which participates in the chain of events that determines the fate of the star. Among the processes of interest, the production of heavy elements in core-collapse supernovae is strongly dependent upon neutrino properties, like the mixing between different species of neutrinos. In this work we study the effects of neutrino oscillations upon the electron fraction as a function of the neutrino mixing parameters, for two schemes: the $1+1$ scheme (one active neutrino and one sterile neutrino) and the $2+1$ scheme (two active neutrinos and one sterile neutrino). We have performed this analysis considering a core-collapse supernovae and determined the physical conditions needed to activate the nuclear reaction chains involved in the r-process. We found that the interactions of the neutrinos with matter and among themselves and the initial amount of sterile neutrinos in the neutrino-sphere might change the electron fraction, therefore affecting the onset of the r-process. We have set constrains on the active-sterile neutrino mixing parameters. They are the square-mass-difference $Δm^2_{14} $, the mixing angle $\sin^2 2θ_{14}$, and the hindrance factor $ξ_s $ for the occupation of sterile neutrinos. The calculations have been performed for different values of $X_α$, which is the fraction of $α$-particles. For $X_α=0$ the r-process is taking place if $Δm^2_{14} \geq 2 \, {\rm eV}^2 $, $\sin^2 2θ_{14} < 0.8 $ and $ξ_s < 0.5$. For larger values of $X_α$ the region of parameters is strongly reduced. The present results are compared to results available in the literature.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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