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arXiv 0704.3930hep-ph
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β衰变中KATRIN对中微子质量和右手电流的灵敏度

The KATRIN sensitivity to the neutrino mass and to right-handed currents in beta decay

J. Bonn, K. Eitel, F. Glück, D. Sevilla-Sanchez, N. Titov

摘要:

卡尔斯鲁厄氚中微子实验KATRIN的目的是确定绝对中微子质量标度下降到0.2 eV,与宇宙学和无中微子双β衰变相比,模型依赖性要小得多。为此目的,在接近氚分子β衰变终点处测量积分电子能谱。端点,连同中微子质量,应拟合从KATRIN数据作为一个自由参数。右手耦合改变了端点附近的电子能谱,因此对中微子质量的精确测定也有一定的影响。统计计算表明,以端点为自由参数,许多β衰变实验所限制的未考虑的右手耦合能使中微子质量的拟合值相对于中微子真实质量的变化不超过5- 10%.错误地使用端点作为固定输入参数,中微子质量的上述变化可能会大得多,数量级为100%,并且在某些情况下,对于大的真实中微子质量值,拟合的中微子质量平方可能是负数。使用固定端点的出版物,并提出了大的右手耦合效应的中微子质量测定是不相关的KATRIN实验。

英文摘要:

The aim of the KArlsruhe TRItium Neutrino experiment KATRIN is the determination of the absolute neutrino mass scale down to 0.2 eV, with essentially smaller model dependence than from cosmology and neutrinoless double beta decay. For this purpose, the integral electron energy spectrum is measured close to the endpoint of molecular tritium beta decay. The endpoint, together with the neutrino mass, should be fitted from the KATRIN data as a free parameter. The right-handed couplings change the electron energy spectrum close to the endpoint, therefore they have some effect also to the precise neutrino mass determination. The statistical calculations show that, using the endpoint as a free parameter, the unaccounted right-handed couplings constrained by many beta decay experiments can change the fitted neutrino mass value, relative to the true neutrino mass, by not larger than about 5-10 %. Using, incorrectly, the endpoint as a fixed input parameter, the above change of the neutrino mass can be much larger, order of 100 %, and for some cases it can happen that for large true neutrino mass value the fitted neutrino mass squared is negative. Publications using fixed endpoint and presenting large right-handed coupling effects to the neutrino mass determination are not relevant for the KATRIN experiment.

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