Evidence for Nonlinear Isotope Shift in Yb
Phys Rev Lett
; 125(12): 123002, 2020 Sep 18.
Article
em En
| MEDLINE
| ID: mdl-33016768
ABSTRACT
We measure isotope shifts for five Yb^{+} isotopes with zero nuclear spin on two narrow optical quadrupole transitions ^{2}S_{1/2}â^{2}D_{3/2}, ^{2}S_{1/2}â^{2}D_{5/2} with an accuracy of â¼300 Hz. The corresponding King plot shows a 3×10^{-7} deviation from linearity at the 3σ uncertainty level. Such a nonlinearity can indicate physics beyond the Standard Model (SM) in the form of a new bosonic force carrier, or arise from higher-order nuclear effects within the SM. We identify the quadratic field shift as a possible nuclear contributor to the nonlinearity at the observed scale, and show how the nonlinearity pattern can be used in future, more accurate measurements to separate a new-boson signal from nuclear effects.
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MEDLINE
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En
Ano de publicação:
2020
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Article