Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Measurement of the running of the fine structure constant below 1 GeV
  with the KLOE detector   The precision measurement of the $d\sigma(e^+e^- \rightarrow \mu^+\mu^-
\gamma)/d\sqrt{s}$ cross section with the photon emitted in the initial state
with the KLOE detector has been used to measure the running of the QED coupling
constant $\alpha(s)$ in the energy range 0.6 $< \sqrt{s} <$ 0.975 GeV in the
time-like region. We were able to achieve a significance of the hadronic
contribution to the running of $\alpha(s)$ of more than 5$\sigma$ with a clear
contribution of the $\rho - \omega$ resonances to the photon propagator. The
real and imaginary part of the shift $\Delta\alpha$ to the running has been
estracted and a fit of the real part allowed us to measure the branching
fraction $BR(\omega \rightarrow \mu^+\mu^-)$ =
(6.6$\pm$1.4$_{stat}$$\pm$1.7$_{syst}$ )$\cdot$10$^{-5}$.

22
The categories of this paper are: chao-dyn
6
The categories of this paper are: astro-ph
2
The categories of this paper are: math
13
The categories of this paper are: quant-ph
37
The categories of this paper are: supr-con
28
The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th
19
The categories of this paper are: eess
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys
14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol