Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Flavor decomposition for the proton helicity parton distribution
  functions   We present, for the first time, an \textit{ab initio} calculation of the
individual up, down and strange quark helicity parton distribution functions
for the proton. The calculation is performed within the twisted mass
clover-improved fermion formulation of lattice QCD using one ensemble of
dynamical up, down, strange and charm quarks with a pion mass of 260 MeV. The
lattice matrix elements are non-perturbatively renormalized and the final
results are presented in the $\overline{ \rm MS}$ scheme at a scale of 2 GeV.
We give results on the $\Delta u^+(x)$ and $\Delta d^+(x)$, including
disconnected quark loop contributions, as well as on the $\Delta s^+(x)$. For
the latter we achieve unprecedented precision compared to the phenomenological
estimates.

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The categories of this paper are: physics
30
The categories of this paper are: q-alg
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
19
The categories of this paper are: eess
6
The categories of this paper are: astro-ph
2
The categories of this paper are: math
18
The categories of this paper are: econ
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con