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

未来几年，TRIUMF将建造和开发一种新的高密度超冷中子源。使用该装置的初始实验是一种新的测量中子电偶极矩（nEDM）。 nEDM的非零值将违反时间反演对称性。标准模型预测nEDM的值为10^{-32} e-cm。但CP违反的新来源是通过对标准模型的修改来预测的，该模型试图解释宇宙的重子不对称性（物质-反物质不对称性）。这些新的源通常使nEDM增加了5个数量级，非常接近目前实验的上限< 2.9*10^{-26} e-cm。我们最近在RCNP的研发测试中取得了很大的成功，为未来的TRIUMF实验做准备。该实验实现了19/cc的UCN密度，这已经比劳厄-朗之万研究所（ILL，法国格勒诺布尔）的0.7/cc大了一个数量级以上，该研究所的实验保持了中子EDM的当前最佳极限。我们的装置的新颖方面将是更小的几何形状，以抑制系统的不确定性和改进的共磁力测量使用超流氦，利用更高密度的UCN源，使用突破性的生产方法与超流氦。UCN来源最近得到了日本科学促进协会和加拿大CFI的资助。来自TRIUMF、Acsion Industries（Pinawa，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和大坂的RCNP承诺为该项目捐款约170万美元。2010年9月20日举行了对UCN项目的国际专家审查，预计随后温尼伯（CFI）、TRIUMF、KEK和RCNP将签署谅解备忘录。2010年4月，NSERC获得了为期三年的运行补助金，用于UCN源的设计和建造以及nEDM实验的研发。加拿大UCN集团正在迅速发展。我们在这里申请的资金是用于额外成员的运作，这些成员将使加拿大UCN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.