Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Origin of Difference between $\overline{d}$ and $\overline{u}$ Partons
  in the Nucleon   Using the Euclidean path-integral formulation for the hadronic tensor, we
show that the violation of the Gottfried sum rule does not come from the
disconnected quark-loop insertion. Rather, it comes from the connected (quark
line) insertion involving quarks propagating in the backward time direction. We
demonstrate this by studying sum rules in terms of the scalar and axial- vector
matrix elements in lattice gauge calculations. The effects of eliminating
backward time propagation are presented.

29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
7
The categories of this paper are: hep-th
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
4
The categories of this paper are: cond-mat
3
The categories of this paper are: physics
35
The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
8
The categories of this paper are: hep-ex