Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Infrared Safe but Infinite: Soft-Gluon Divergences Inside the Physical
  Region   We show that QCD observables defined as infrared- and collinear-safe,
according to the usual Sterman-Weinberg criteria, can nevertheless be infinite
at accessible points inside phase space, to any finite order of perturbation
theory. Infrared finiteness is restored after resummation of divergent terms to
all orders. The resulting characteristic structure, which we call a Sudakov
shoulder, represents an interesting new class of QCD predictions.

29
The categories of this paper are: funct-an
3
The categories of this paper are: physics
32
The categories of this paper are: atom-ph
30
The categories of this paper are: q-alg
4
The categories of this paper are: cond-mat
35
The categories of this paper are: mtrl-th
11
The categories of this paper are: hep-lat
24
The categories of this paper are: dg-ga
18
The categories of this paper are: econ
15
The categories of this paper are: nucl-ex
33
The categories of this paper are: plasm-ph
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
21
The categories of this paper are: adap-org
20
The categories of this paper are: acc-phys
31
The categories of this paper are: ao-sci