Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evidence of Two-Source King Plot Nonlinearity in Spectroscopic Search
  for New Boson   Optical precision spectroscopy of isotope shifts can be used to test for new
forces beyond the Standard Model, and to determine basic properties of atomic
nuclei. We measure isotope shifts on the highly forbidden ${}^2S_{1/2}
\rightarrow {}^2F_{7/2}$ octupole transition of trapped
$^{168,170,172,174,176}$Yb ions. When combined with previous measurements in
Yb$^+$ and very recent measurements in Yb, the data reveal a King plot
nonlinearity of up to 240$\sigma$. The trends exhibited by experimental data
are explained by nuclear density functional theory calculations with the Fayans
functional. We also find, with 4.3$\sigma$ confidence, that there is a second
distinct source of nonlinearity, and discuss its possible origin.

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The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
28
The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ
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The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
19
The categories of this paper are: eess
6
The categories of this paper are: astro-ph
30
The categories of this paper are: q-alg
36
The categories of this paper are: cmp-lg