Anapole Moment Studies in Francium

研究人员将研究最不稳定的自然存在的元素<$的原子核内的弱相互作用，即导致放射性的力。与其他三种基本力不同，弱相互作用并不是在所有情况下都对称地起作用。它在一组空间坐标中表现为一种方式，而当这些坐标被交换为镜像时，则表现为另一种方式，这种现象称为奇偶违反。实验将探索这种内在的手性表现在不同同位素的<$限制在激光阱和微波激发。原子的“禁止”（极其罕见）跃迁与原子核内电流的一种特殊形状有关，即沿着百吉饼表面的anapole时刻。到目前为止，这只在铯的一种同位素中观察到。由于阿那极矩受到导致宇称破坏弱相互作用的中子数量的强烈影响，因此改变同位素并重复实验将允许测量表征核中弱相互作用的参数。这项国际努力在加拿大温哥华的加速器TRIUMF进行，将使两名研究生能够接受原子、分子和光学物理与核物理之间的边界方面的教育。当地本科生将在学年期间参加;在夏季，墨西哥学生将通过由Sociedad Mexicana de Física协调的计划参加。

The researchers will investigate aspects of the weak interaction, the force responsible for radioactivity, inside the nucleus of the least stable naturally occurring element, francium. Unlike the other three fundamental forces, the weak interaction does not act symmetrically in all circumstances. It behaves one way in one set of spatial coordinates, and another way when those coordinates are exchanged for a mirror image, a phenomenon called parity violation. The experiments will explore manifestations of this intrinsic handedness in different isotopes of francium confined in a laser trap and excited with microwaves. "Forbidden" (extremely rare) transitions by the atoms are linked to the presence of a peculiar shape of the current inside the nucleus, the anapole moment, that follows the surface of a bagel. To date this has only been observed in one isotope of cesium. Because the anapole moment is strongly affected by the number of neutrons that contribute to the parity-violating weak interaction, changing the isotope and repeating the experiment will allow measurements of parameters that characterize the weak interaction in the nucleus. This international effort, taking place at TRIUMF, the accelerator in Vancouver Canada, will allow two graduate students to be educated in the boundary between atomic, molecular and optical physics and nuclear physics. Local undergraduates will participate during the academic year; and in the summer Mexican students will take part through a program coordinated by the Sociedad Mexicana de Física.