Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Measurement of the W-Pair Production Cross Section and W-Decay Branching
  Fractions in e+e- Interactions at sqrt{s}=189GeV   The data collected by the L3 experiment at LEP at a centre-of-mass energy of
188.6 GeV are used to measure the W-pair production cross section and the
W-boson decay branching fractions. These data correspond to an integrated
luminosity of 176.8pb^-1. The total cross section for W-pair production,
combining all final states, is measured to be sigma_WW = 16.24 +/- 0.37(stat.)
+/- 0.22(syst.) pb. Including our data collected at lower centre-of-mass
energies, the hadronic branching fraction of the W-boson is determined to be
B(W ->qq) = [68.20 +/- 0.68 (stat.) +/- 0.33 (syst.) ] %. The results agree
with the Standard Model predictions.

30
The categories of this paper are: q-alg
13
The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat
28
The categories of this paper are: alg-geom
15
The categories of this paper are: nucl-ex
2
The categories of this paper are: math
20
The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
14
The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
1
The categories of this paper are: cs
29
The categories of this paper are: funct-an
6
The categories of this paper are: astro-ph
16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin