其他

2018-05-26


学术沙龙(5月24日 

题目: 

年轻的粒子: 中微子的过去,现在与将来


报告人: 

贺远强 副教授


地点: 

南校园十友堂300报告厅


时间: 

5月24日 周四下午 14:30-16:00


主持人:

王为 教授


摘要:

粒子物理从古希腊时代提出世界万物的基本组成元素开始,到18世纪末期发现电子。慢慢的进入发展期。中微子作为现代标准模型的基本粒子,在50年代被证实存在。与其他复合粒子不同,中微子的探测非常困难,至今60年过去了,它的特性还没有完全了解。在本报告中,我将介绍中微子的历史流传,当代及今日的发展,实验原理与难度,以及未来的方向。进一步说明中微子可能的应用和这个领域在世界上的进展。

报告人简介:


贺远强博士于2006年毕业于香港中文大学,2008年取得硕士学位后赴及美国Virginia Tech。于2014年取得博士学位。硕博阶段参与开发香港第一个粒子物理地下实验室,并加入了大亚湾中微子实验进行前期开发,运行和数据分析。博士后研究主要为中微子物理,反应堆探测开发和宇宙暗物质探测(LZ)实验。参与了包括美国,欧洲多个百人以上的粒子物理实验团队。目前研究方向主要为反应堆中微子物理与应用,探测器与系统开发,以及暗物质的探测和时间分辨。

学术讲座(5月24日)

题目: 

Uncertainty study in analyzing the Reactor Neutrino Anomaly based on the nuclear structure physics


报告人: 

王小保 教授 (湖州师范大学)


地点: 

南校园十友堂300报告厅


时间: 

5月24日 周四下午 16:00-17:00


主持人:

Dr. Neill Raper (王为教授博后)


摘要:

The Daya Bay (DB) reactor neutrino experiments confirm the “reactor neutrino anomaly” in that the measured value of \sigma_f is about 5.1% below that predicted by the model spectra of Huber and Mueller (H-M). Such anomaly could be potentially extremely important for the possible existence of sterile neutrino. Thus, extensive recent literature appears, to study the origin of the anomaly.


In this talk, I would like to discuss some topic related to the uncertainties of the antineutrino spectra. To obtain the antineutrino spectra theoretically,  so-called summation method or by the conversion method can be used. For both methods, all corrections to β decay that can affect the spectra at the few percent level are normally included. There are four subdominant corrections to β decay that must be considered in calculating the antineutrino spectra. These are the recoil, radiative, finite-size, and weak magnetism corrections. The recoil correction is quite small, and the radiative correction has been taken from the work of Sirlin, both before and since the occurrence of the anomaly. In all cases, the finite-size and weak magnetism corrections that were applied involve some level of approximation. We have checked the validity of the nuclear structure assumption, particularly for allowed fission-fragment β decays.


I would also introduce our recent work of the analysis of the Daya Bay Reactor antineutrino flux changes with fuel burnup. We find that the discrepancy between current model predictions and the Daya Bay results can be traced to the original measured 235U/239Pu ratio of the fission β spectra that were used as a base for the expected antineutrino fluxes. We conclude that there is currently not enough information to use the antineutrino flux changes to rule out the possible existence of sterile neutrinos. The concept of finite structure of the antineutrino spectra from a Nuclear Reactor will also be talked briefly.


报告人简介:


王小保教授,2007年本科毕业于北京大学物理学院物理学专业,2012年获北京大学博士学位。2012年-2014年在芬兰于韦斯屈莱大学从事博士后研究工作;2015-2016年在美国洛斯阿拉莫斯国家实验室做访问学者;目前,作为高层次引进人才在湖州师范学院理学院工作。迄今,在国内外本领域高水平期刊上发表论文21篇,近三年来主持国家基金项目3项,先后获得湖州市青年科技奖、浙江省高等学校中青年学科带头人等荣誉称号。


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