Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Resummation of Large Logarithms in the Electromagnetic Form factor of
  pion   In the collinear factorization of the form factor for the transition
$\gamma^* \pi^0 \to \pi$ the hard part contains double log terms. These terms
will spoil the perturbative expansion of the hard part. A simple exponentiation
for resummation leads to divergent results. We study the resummation of these
double log's. We make an analysis to show the origin of the double log's. With
the understanding of the origin one can introduce soft factors and Nonstandard
Light-Cone Wave Functions(NLCWF) to derive a factorized form for the form
factor, where the hard part does not contain the double log's. There is a
perturbative relation between NLCWF and the standard Light-Cone Wave
Function(LCWF). Beside the renormalization scale $\mu$ the introduced NLCWF's
and soft factors have extra scales to characterize the double log's. Using the
evolutions of the extra scales and the relation we can do the resummation of
the double log's perturbatively in sense that LCWF's are the only
nonpertubative objects in the resumed formula. Our results with some models of
LCWF show that there is a significant difference between numerical predictions
with or without the resummation.

1
The categories of this paper are: cs
27
The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio
8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
11
The categories of this paper are: hep-lat
16
The categories of this paper are: stat
6
The categories of this paper are: astro-ph
4
The categories of this paper are: cond-mat
5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
21
The categories of this paper are: adap-org
28
The categories of this paper are: alg-geom
22
The categories of this paper are: chao-dyn
15
The categories of this paper are: nucl-ex