12:30-13:30
Speaker : Dr. Yasuhiro YAMAMOTO (NCTS) 

Abstract :
The atomic spectrum is affected by the differences in the nuclear
state among isotopes.
This spectrum change is called the isotope shift.
It is known and tested well that the isotope shifts for two distinct
follow a linear relation so called the King linearity.
Recently, it has been proposed that the violation of the linear
relation can be a good probe of the weakly interacting light boson.
In the last year, such a linearity violation was reported.
However, the result conflicts with other experimental constraints if
the violation is attributed to the new force.
Therefore, it should originate from the higher order effects of the
Standard Model.
While new and precise results are rapidly obtained by experiments, the
numerical progress to understand the observed violation is quite poor.
We proposed a method to eliminate the higher order isotope shifts with
the generalization of the King linearity.
In collaboration with the quantum optics group at Kyoto University,
we applied this method to the observed non linearity in the King
relation with their new measurement of the isotope shift using neutral
Ytterbium.
Finally, we obtained the new experimental bound to the weakly
interacting light boson.
I will also introduce some recent progress on this topic.
This talk is based on 1710.11443, 1911.05345, and 2110.13544.