Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: High Precision determination of the pi, K, D and D_s decay constants
  from lattice QCD   We determine $D$ and $D_s$ decay constants from lattice QCD with 2% errors, 4
times better than experiment and previous theory: $f_{D_s}$ = 241(3) MeV, $f_D$
= 207(4) MeV and $f_{D_s}/f_D$ = 1.164(11).
  We also obtain $f_K/f_{\pi}$ = 1.189(7) and $(f_{D_s}/f_D)/(f_K/f_{\pi})$ =
0.979(11). Combining with experiment gives $V_{us}$=0.2262(14) and
$V_{cs}/V_{cd}$ of 4.43(41). We use a highly improved quark discretization on
MILC gluon fields that include realistic sea quarks fixing the $u/d, s$ and $c$
masses from the $\pi$, $K$, and $\eta_c$ meson masses. This allows a stringent
test against experiment for $D$ and $D_s$ masses for the first time (to within
7 MeV).

28
The categories of this paper are: alg-geom
6
The categories of this paper are: astro-ph
34
The categories of this paper are: chem-ph
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
3
The categories of this paper are: physics
33
The categories of this paper are: plasm-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: atom-ph
20
The categories of this paper are: acc-phys
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The categories of this paper are: stat
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The categories of this paper are: supr-con
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The categories of this paper are: q-fin
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The categories of this paper are: gr-qc