Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Observation of photon-induced $W^+W^-$ production in $pp$ collisions at
  $\sqrt{s}=13$ TeV using the ATLAS detector   This letter reports the observation of photon-induced production of $W$-boson
pairs, $\gamma\gamma\rightarrow WW$. The analysis uses 139 fb$^{-1}$ of LHC
proton-proton collision data taken at $\sqrt{s}=13$ TeV recorded by the ATLAS
experiment during the years 2015-2018. The measurement is performed selecting
one electron and one muon, corresponding to the decay of the diboson system as
$WW\rightarrow e^\pm\nu\mu^\mp\nu$ final state. The background-only hypothesis
is rejected with a significance of well above 5 standard deviations consistent
with the expectation from Monte Carlo simulation. A cross section for the
$\gamma\gamma\rightarrow WW$ process of 3.13$\pm$0.31(stat.)$\pm$0.28(syst.) fb
is measured in a fiducial volume close to the acceptance of the detector, by
requiring an electron and a muon of opposite signs with large dilepton
transverse momentum and exactly zero additional charged particles. This is
found to be in agreement with the Standard Model prediction.

23
The categories of this paper are: solv-int
26
The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol
4
The categories of this paper are: cond-mat
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
28
The categories of this paper are: alg-geom
14
The categories of this paper are: math-ph
17
The categories of this paper are: q-fin
16
The categories of this paper are: stat
3
The categories of this paper are: physics
2
The categories of this paper are: math
0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
29
The categories of this paper are: funct-an