Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Improved isotope-shift-based bounds on bosons beyond the Standard Model
  through measurements of the $^2$D$_{3/2} - ^2$D$_{5/2}$ interval in Ca$^+$   We perform high-resolution spectroscopy of the $3$d$~^2$D$_{3/2} -
3$d$~^2$D$_{5/2}$ interval in all stable even isotopes of $^A$Ca$^+$ (A = 40,
42, 44, 46 and 48) with an accuracy of $\sim$ 20 Hz using direct frequency-comb
Raman spectroscopy. Combining these data with isotope shift measurements of the
4s$~^2$S$_{1/2} \leftrightarrow 3$d$~^2$D$_{5/2}$ transition, we carry out a
King plot analysis with unprecedented sensitivity to coupling between electrons
and neutrons by bosons beyond the Standard Model. Furthermore, we estimate the
sensitivity to such bosons from equivalent spectroscopy in Ba$^+$ and Yb$^+$.
Finally, the data yield isotope shifts of the 4s$~^2$S$_{1/2} \leftrightarrow
3$d$~^2$D$_{3/2}$ transition at 10 part-per-billion through combination with
recent data of Knollmann et al (2019).

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The categories of this paper are: funct-an
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The categories of this paper are: alg-geom
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
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The categories of this paper are: chem-ph
36
The categories of this paper are: cmp-lg
6
The categories of this paper are: astro-ph
30
The categories of this paper are: q-alg
4
The categories of this paper are: cond-mat
2
The categories of this paper are: math
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The categories of this paper are: eess
11
The categories of this paper are: hep-lat
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The categories of this paper are: q-fin
33
The categories of this paper are: plasm-ph
7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con