Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On power corrections to event shapes   Recent work on the theme of power corrections in perturbative QCD is briefly
reviewed, with an emphasis on event shapes in e+ e- annihilation. The
factorization of soft gluon effects is the main tool: it leads to resummation,
and thus highlights the limitations of perturbation theory, pointing to
nonperturbative corrections whose size can be estimated. Power corrections can
be resummed into shape functions, for which QCD--based models are available.
Theoretical progress is closing in on the nonperturbative frontier.

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The categories of this paper are: mtrl-th
10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
11
The categories of this paper are: hep-lat
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
5
The categories of this paper are: gr-qc
2
The categories of this paper are: math
19
The categories of this paper are: eess
26
The categories of this paper are: bayes-an
31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
4
The categories of this paper are: cond-mat