Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Order of Magnitude Smaller Limit on the Electric Dipole Moment of the
  Electron   The Standard Model (SM) of particle physics fails to explain dark matter and
why matter survived annihilation with antimatter following the Big Bang.
Extensions to the SM, such as weak-scale Supersymmetry, may explain one or both
of these phenomena by positing the existence of new particles and interactions
that are asymmetric under time-reversal (T). These theories nearly always
predict a small, yet potentially measurable ($10^{-27}$-$10^{-30}$ $e$ cm)
electron electric dipole moment (EDM, $d_e$), which is an asymmetric charge
distribution along the spin ($\vec{S}$). The EDM is also asymmetric under T.
Using the polar molecule thorium monoxide (ThO), we measure $d_e = (-2.1 \pm
3.7_\mathrm{stat} \pm 2.5_\mathrm{syst})\times 10^{-29}$ $e$ cm. This
corresponds to an upper limit of $|d_e| < 8.7\times 10^{-29}$ $e$ cm with 90
percent confidence, an order of magnitude improvement in sensitivity compared
to the previous best limits. Our result constrains T-violating physics at the
TeV energy scale.

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The categories of this paper are: math
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess
36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol
15
The categories of this paper are: nucl-ex
35
The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con
5
The categories of this paper are: gr-qc
6
The categories of this paper are: astro-ph
18
The categories of this paper are: econ
16
The categories of this paper are: stat
26
The categories of this paper are: bayes-an
12
The categories of this paper are: nucl-th
33
The categories of this paper are: plasm-ph