Ultracold Neutrons at TRIUMF - Bridging grant application for new collaboration members

一个新的高密度超冷中子（UCN）源将在未来几年在TRIUMF建造和开发。该装置的初始实验是中子电偶极矩（nEDM）的一种新的测量方法。nEDM的非零值将违反时间反转对称性。标准模型预测nEDM的值为10^{-32}-cm。但是新的cp违逆源是通过对标准模型的修正来预测的，该模型试图解释宇宙的重子不对称（物质-反物质不对称）。这些新源通常将nEDM增加5个数量级，诱人地接近当前的实验上限< 2.9*10^{-26}-cm。我们最近在RCNP为未来的TRIUMF实验进行的研发测试中取得了很大的成功。实验达到了19/cc的UCN密度，在法国格勒诺布尔的Laue-Langevin研究所，UCN密度已经比0.7/cc高出一个数量级，该研究所的实验拥有目前中子EDM的最佳极限。该装置的新颖之处将是更小的几何形状，以抑制系统的不确定性，并使用Xe改进共磁计，利用超流氦的突破性生产方法，利用更高密度的UCN源。UCN的来源最近得到了日本科学促进会和加拿大CFI的资助。来自TRIUMF、Acsion Industries（皮纳瓦，MB）、马尼托巴政府和温尼伯大学的合作伙伴捐款也将支持该项目。项目总成本为1090万美元。此外，KEK和大阪的RCNP承诺为该项目捐款约170万美元。2010年9月20日，国际专家对UCN项目进行了审查，预计随后将在温尼伯（CFI）、TRIUMF、KEK和RCNP之间签署谅解备忘录。2010年4月，NSERC授予了一项为期三年的运营拨款，用于UCN源的设计和建设以及nEDM实验的研发。加拿大UCN组织正在迅速发展。我们在此要求的资金用于增加成员的运作，他们将使加拿大自然保护联盟合作的成员名单增加一倍。

A new high-density ultracold neutron (UCN) source will be constructed and developed at TRIUMF over the coming years. The initial experiment using the facility is a new measurement of the neutron electric dipole moment (nEDM). A non-zero value of the nEDM would violate time-reversal symmetry. The standard model predicts a value of 10^{-32} e-cm for the nEDM. But new sources of CP-violation are predicted by modifications to the standard model which seek to explain the baryon asymmetry (matter-antimatter asymmetry) of the universe. These new sources generally increase the nEDM by five orders of magnitude, tantalizingly close to the current experimental upper limit of < 2.9*10^{-26} e-cm. We have had a great deal of success at RCNP recently in R&D tests for this future experiment for TRIUMF. UCN density of 19/cc is achieved for the experiment, which is already more than an order of magnitude greater than 0.7/cc at Institut Laue-Langevin (ILL, Grenoble, France), whose experiment holds current best limit on neutron EDM. The novel aspects of our setup would be smaller geometry to suppress systematic uncertainty and improved co-magnetometry using Xe, taking advantage of the higher density of UCN source using a breakthrough production method with superfluid helium. The UCN source has recently been funded by the Japan Society for the Promotion of Science, and by CFI in Canada. Partner contributions from TRIUMF, Acsion Industries (Pinawa, MB), the Government of Manitoba, and the University of Winnipeg, will also support the project. The total project cost is $10.9M. In addition, KEK and RCNP in Osaka pledged ~$1.7M contribution to the project. An international expert review of the UCN project was held on September 20, 2010, which is expected to be followed by the signing of MOU among Winnipeg (CFI), TRIUMF, KEK, and RCNP. In April 2010, a three-year NSERC operation grant was awarded for the design and construction of UCN source and R&D of the nEDM experiment. The Canadian UCN group is rapidly growing. The funds we request here are for the operation for the additional members who will double the member list of the Canadian UCN collaboration.