Isotopic variation of parity violation in atomic ytterbium

• Published in: Nature physics 2019-02, Vol.15 (2), p.120-123
• Main Authors: Antypas, D., Fabricant, A., Stalnaker, J. E., Tsigutkin, K., Flambaum, V. V., Budker, D.
• Format: Article
• Language: English
• Subjects: 639/766/36; 639/766/387; 639/766/419; Atomic; Classical and Continuum Physics; Complex Systems; Condensed Matter Physics; Electric fields; Geometry; Letter; Light; Magnetic fields; Mathematical and Computational Physics; Mathematical models; Molecular; Noise; Nuclei (nuclear physics); Optical and Plasma Physics; Parity; Physics; Physics and Astronomy; Theoretical; Ytterbium; Ytterbium isotopes
• ISSN: 1745-2473; 1745-2481
• DOI: 10.1038/s41567-018-0312-8

The weak force is the only fundamental interaction known to violate the symmetry with respect to spatial inversion (parity). This parity violation can be used to isolate the effects of the weak interaction in atomic systems, providing a unique, low-energy test of the standard model (see, for example, reviews 1 – 3 ). These experiments are primarily sensitive to the weak force between the valence electrons and the nucleus, mediated by the neutral Z 0 boson and dependent on the weak charge of the nucleus, Q w . The standard model parameter Q w was most precisely determined in caesium 4 , 5 and has provided a stringent test of the standard model at low energy. The standard model also predicts a variation of Q w with the number of neutrons in the nucleus, an effect whose direct observation we are reporting here. Our studies, made on a chain of ytterbium isotopes, provide a measurement of isotopic variation in atomic parity violation, confirm the predicted standard model Q w scaling and offer information about an additional Z ′ boson. The weak interaction between the nucleus and the electrons in a chain of Yb isotopes is measured with tabletop atomic physics techniques. The dependence of the interaction strength on the number of neutrons confirms the prediction by standard model.