Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Phenomenology of TMDs   We present a review of current Transverse Momentum Dependent (TMD)
phenomenology focusing our attention on the unpolarized TMD parton distribution
function and the Sivers function. The paper introduces and comments about the
new Collins-Soper-Sterman (CSS) TMD evolution formalism. We make use of a
selection of results obtained by several groups to illustrate the achievements
and the failures of the simple Gaussian approach and the TMD CSS evolution
formalism.

18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
4
The categories of this paper are: cond-mat
17
The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con
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
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
5
The categories of this paper are: gr-qc
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
6
The categories of this paper are: astro-ph
25
The categories of this paper are: patt-sol