Prospects for measuring the electric dipole moment of the electron using electrically trapped polar molecules.
Prospects for measuring the electric dipole moment of the electron using electrically trapped polar molecules.
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DOI：
10.1039/b820625b
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发表时间：
2008-11
影响因子：
3.4
通讯作者：
Michael Tarbutt;J. Hudson;B. Sauer;E. Hinds
中科院分区：
文献类型：
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作者：
Michael Tarbutt;J. Hudson;B. Sauer;E. Hinds
重极性分子可以用来测量电子的电偶极矩，这是超越标准模型的一个敏感的物理探针。该值是通过测量分子自旋在垂直于外加电场的平面上的进动来确定的。这种进动的持续时间越长，测量的精度就越高。对于处于陷阱中的分子来说，这种相干时间可能非常长。我们评估了中性分子被电捕获的实验的灵敏度，并将其与分子束中的等效测量进行比较。我们考虑使用Stark减速器来加载来自超音速源的陷阱，并计算了YbF分子在强场寻找和弱场寻找状态下的减速效率。在陷阱中保持1秒的时间，统计灵敏度可能比光束实验高10倍，如果陷阱可以从更大的发射源加载，这可能会进一步提高5倍。我们研究了由于陷阱中场的不均匀性而造成的一些影响，发现电场方向的旋转导致了不均匀的几何相移，这是基于陷阱的敏感测量的主要障碍。
Heavy polar molecules can be used to measure the electric dipole moment of the electron, which is a sensitive probe of physics beyond the Standard Model. The value is determined by measuring the precession of the molecule's spin in a plane perpendicular to an applied electric field. The longer this precession evolves coherently, the higher the precision of the measurement. For molecules in a trap, this coherence time could be very long indeed. We evaluate the sensitivity of an experiment where neutral molecules are trapped electrically, and compare this to an equivalent measurement in a molecular beam. We consider the use of a Stark decelerator to load the trap from a supersonic source, and calculate the deceleration efficiency for YbF molecules in both strong-field seeking and weak-field seeking states. With a 1 s holding time in the trap, the statistical sensitivity could be ten times higher than it is in the beam experiment, and this could improve by a further factor of five if the trap can be loaded from a source of larger emittance. We study some effects due to field inhomogeneity in the trap and find that rotation of the electric field direction, leading to an inhomogeneous geometric phase shift, is the primary obstacle to a sensitive trap-based measurement.