Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Perturbative QCD analysis of $B(B\to Xl\bar{\nu})$, charm yield $<n_c>$
  in B decay, and $\tau (\Lambda_b)/\tau (B_d)$   We apply perturbative QCD factorization theorems to inclusive heavy hadron
decays, and obtain simultaneously a low semileptonic branching ratio $B(B\to
Xl\bar{\nu})=10.16%$, the average charm yield $<n_c>=1.17$ per $B$ decay, a
small lifetime ratio $\tau(\Lambda_b)/\tau(B_d)=0.78$, and the correct absolute
decay widths of the $B$ meson and of the $\Lambda_b$ baryon.

29
The categories of this paper are: funct-an
25
The categories of this paper are: patt-sol
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The categories of this paper are: eess
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The categories of this paper are: alg-geom
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The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
7
The categories of this paper are: hep-th
5
The categories of this paper are: gr-qc
3
The categories of this paper are: physics
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The categories of this paper are: supr-con
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The categories of this paper are: dg-ga
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The categories of this paper are: adap-org
6
The categories of this paper are: astro-ph
12
The categories of this paper are: nucl-th
23
The categories of this paper are: solv-int
36
The categories of this paper are: cmp-lg