Determination of the mass of the Electron anti-neutrino via beta decay

通过β衰变测定电子反中微子的质量

• 批准号: 0457194
• 负责人: Manfred Fink
• 金额: --
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2009-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0457194&HistoricalAwards=false
• 关键词: Determination; mass; Electron; anti; neutrino

Summary of NEXTEX, the Neutrino mass EXperiment at TEXasThis project is designed to determine the mass of the electron neutrino from observation of the end point of the beta-decay spectrum of molecular tritium. The current limit on neutrino mass from this technique is around 2 eV/c2, but this result appears to be dominated by systematic uncertainties. The mass is expected to be at least an order of magnitude less than this value, possibly around 0.2 eV/c2. NEXTEX proposes to make this end point observation using purely electrostatic analysis of the electrons produced in the beta decays, unlike the previous measurements and KATRIN, the experiment that is expected to provide the next major step in accuracy, all of which utilized magnetic analysis of the electrons resulting from the beta decay. Additional features of the NEXTEX apparatus include use of an electron gun to calibrate the apparatus to better than 1 eV via observation of the electron diffraction pattern produced at its detector location. The proposed accuracy of NEXTEX is better than 0.8 eV/c2 for the mass of the electron neutrino. Thus NEXTEX is not expected to achieve the accuracy of KATRIN, which is designed to provide an accuracy of 0.2 eV/c2. However, NEXTEX may well produce a measurement sooner than can KATRIN, and it may produce important identifications of systematic uncertainties that are difficult to anticipate until the measurements are extended below present levels of accuracy.NEXTEX is a collaboration of 6 universities, and is headed by the group at the University of Texas. Thus it involves several graduate students in its efforts. Its broader impacts certainly include the impact it will have on fundamental physics by providing a new limit on the mass of the electron neutrino as obtained from direct measurement.

NextEx的摘要，Texasthis项目的中微子质量实验旨在确定电子中微子的质量，从观察分子trilecular tritium的β-末端谱的终点。 该技术对中微子质量的当前限制约为2 eV/c2，但该结果似乎由系统的不确定性主导。 预计质量的数量级至少要比该值小，可能约为0.2 eV/c2。 NextEx建议使用对β衰变中产生的电子的纯静电分析来对此终点进行观察，与先前的测量和Katrin不同，该实验预计将提供下一个准确性的主要步骤，所有这些实验都利用了Beta衰变对电子进行的磁分析。 NextEx设备的其他功能包括使用电子枪来校准该设备通过观察其检测器位置产生的电子衍射模式，从而更好地校准了该设备。 对于电子中微子的质量，NextEX的提议精度大于0.8 eV/c2。 因此，预计NextEx不会达到Katrin的准确性，Katrin的精度旨在提供0.2 eV/c2的精度。 但是，NextEx可能比Katrin更快地产生测量值，并且可能会产生重要的系统不确定性的重要识别，直到将测量值扩展到当前的准确性水平以下。Nextex是6所大学的合作，并且由德克萨斯大学的小组领导。 因此，它涉及几个研究生的努力。 它的广泛影响当然包括它将对基本物理的影响，通过对直接测量获得的电子中微子的质量提供新的限制。