Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Measuring cal B(D^+ --> mu^+ nu) and the Pseudoscalar Decay Constant
  f_D^+   In 60 inverse-pb of data taken on the psi(3770) resonance with the CLEO-c
detector, we find 8 D+ -> mu+ nu decay candidates that are mostly signal,
containing only 1 estimated background. Using this statistically compelling
sample, we measure a value of B(D+ -> mu+ nu) = (3.5 +/- 1.4 +/- 0.6) x10^(-4),
and determine fD+=(202 +/- 41 +/-17) MeV.

10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
34
The categories of this paper are: chem-ph
21
The categories of this paper are: adap-org
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
18
The categories of this paper are: econ
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn