Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Helicity Evolution at Small-x   We construct small-x evolution equations which can be used to calculate quark
and anti-quark helicity TMDs and PDFs, along with the $g_1$ structure function.
These evolution equations resum powers of $\alpha_s \, \ln^2 (1/x)$ in the
polarization-dependent evolution along with the powers of $\alpha_s \, \ln
(1/x)$ in the unpolarized evolution which includes saturation effects. The
equations are written in an operator form in terms of polarization-dependent
Wilson line-like operators. While the equations do not close in general, they
become closed and self-contained systems of non-linear equations in the
large-$N_c$ and large-$N_c \, \& \, N_f$ limits. As a cross-check, in the
ladder approximation, our equations map onto the same ladder limit of the
infrared evolution equations for $g_1$ structure function derived previously by
Bartels, Ermolaev and Ryskin.

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The categories of this paper are: astro-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: chao-dyn
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The categories of this paper are: math
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The categories of this paper are: nucl-th
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The categories of this paper are: ao-sci
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The categories of this paper are: atom-ph
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The categories of this paper are: q-fin
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The categories of this paper are: econ
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The categories of this paper are: patt-sol
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-th
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The categories of this paper are: chem-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: hep-lat
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The categories of this paper are: dg-ga