Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hadronic light-by-light contribution to $(g-2)_\mu$: a dispersive
  approach   After a brief introduction on ongoing experimental and theoretical activities
on $(g-2)_\mu$, we report on recent progress in approaching the calculation of
the hadronic light-by-light contribution with dispersive methods. General
properties of the four-point function of the electromagnetic current in QCD,
its Lorentz decomposition and dispersive representation are discussed. On this
basis a numerical estimate for the pion box contribution and its rescattering
corrections is obtained. We conclude with an outlook for this approach to the
calculation of hadronic light-by-light.

36
The categories of this paper are: cmp-lg
24
The categories of this paper are: dg-ga
19
The categories of this paper are: eess
5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph
25
The categories of this paper are: patt-sol
2
The categories of this paper are: math
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
7
The categories of this paper are: hep-th
4
The categories of this paper are: cond-mat
26
The categories of this paper are: bayes-an
29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph