Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Measurement of the fine-structure constant as a test of the Standard
  Model   Measurements of the fine-structure constant alpha require methods from across
subfields and are thus powerful tests of the consistency of theory and
experiment in physics. Using the recoil frequency of cesium-133 atoms in a
matter-wave interferometer, we recorded the most accurate measurement of the
fine-structure constant to date: alpha = 1/137.035999046(27) at 2.0 x 10^-10
accuracy. Using multiphoton interactions (Bragg diffraction and Bloch
oscillations), we demonstrate the largest phase (12 million radians) of any
Ramsey-Borde interferometer and control systematic effects at a level of 0.12
parts per billion. Comparison with Penning trap measurements of the electron
gyromagnetic anomaly ge-2 via the Standard Model of particle physics is now
limited by the uncertainty in ge-2; a 2.5 sigma tension rejects dark photons as
the reason for the unexplained part of the muon's magnetic moment at a 99
percent confidence level. Implications for dark-sector candidates and electron
substructure may be a sign of physics beyond the Standard Model that warrants
further investigation.

15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess
0
The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th
11
The categories of this paper are: hep-lat
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
21
The categories of this paper are: adap-org
13
The categories of this paper are: quant-ph
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
17
The categories of this paper are: q-fin