Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spin effects in the fragmentation of transversely polarized and
  unpolarized quarks   We study the fragmentation of a transversely polarized quark into a non
collinear (k_T not= 0) spinless hadron and the fragmentation of an unpolarized
quark into a non collinear transversely polarized spin 1/2 baryon. These
nonperturbative properties are described by spin and k_T dependent
fragmentation functions and are revealed in the observation of single spin
asymmetries. Recent data on the production of pions in polarized semi-inclusive
DIS and long known data on Lambda polarization in unpolarized p-N processes are
considered: these new fragmentation functions can describe the experimental
results and the single spin effects in the quark fragmentation turn out to be
surprisingly large.

14
The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph
20
The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th
31
The categories of this paper are: ao-sci
32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
27
The categories of this paper are: comp-gas
21
The categories of this paper are: adap-org
8
The categories of this paper are: hep-ex
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
37
The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex
23
The categories of this paper are: solv-int