Precise 8B solar neutrino spectrum for neutrino oscillation analysis

来自8B的太阳中微子光谱是研究超越标准模型的中微子振荡的最精确观测之一。在超级神冈观测到的中微子光谱最大的不确定性之一是8B中微子发射后的光谱形状因子。在本研究中，形状因子项中的弱磁性和轴向电荷矩阵元素是直接由β衰变实验结果确定的。首次基于实验不确定度确定了形状因子的不确定度。

Solar neutrino spectrum from 8B is one of the most precise observables to investigate the neutrino oscillation beyond the standard model. One of the largest uncertainties of neutrino spectrum observed at Super-Kamiokande is the spectral shape factor just after the neutrino emission from 8B. In this study, the weak magnetism and axial charge matrix elements, which are the terms in shape factor, were determined directly from experimental results of beta decay. Uncertainties in the shape factor were determined based on experimental uncertainties for the first time.