Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Long vs. short distance dispersive two-photon K_L \to \mu^+ \mu^-
  amplitude   We report on the calculation of the two-loop electroweak, two-photon mediated
short-distance dispersive K_L \to \mu^+\mu^- decay amplitude. QCD corrections
change the sign of this contribution and reduce it by an order of magnitude.
The resulting amplitude enables us to provide a constraint on the otherwise
uncertain long-distance dispersive amplitude.

5
The categories of this paper are: gr-qc
29
The categories of this paper are: funct-an
28
The categories of this paper are: alg-geom
33
The categories of this paper are: plasm-ph
13
The categories of this paper are: quant-ph
17
The categories of this paper are: q-fin
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
27
The categories of this paper are: comp-gas
34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys
19
The categories of this paper are: eess
10
The categories of this paper are: q-bio
2
The categories of this paper are: math
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin