Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evidence for the associated production of the Higgs boson and a top
  quark pair with the ATLAS detector   A search for the associated production of the Higgs boson with a top quark
pair ($t\bar t H$) is reported. The search is performed in multilepton final
states using a dataset corresponding to an integrated luminosity of 36.1
fb$^{-1}$ of proton--proton collision data recorded by the ATLAS experiment at
a center-of-mass energy $\sqrt{s} = 13$ TeV at the Large Hadron Collider. Higgs
boson decays to $WW^*$, $\tau\tau$, and $ZZ^*$ are targeted. Seven final
states, categorized by the number and flavor of charged-lepton candidates, are
examined for the presence of the Standard Model Higgs boson with a mass of 125
GeV and a pair of top quarks. An excess of events over the expected background
from Standard Model processes is found with an observed significance of 4.1
standard deviations, compared to an expectation of 2.8 standard deviations. The
best fit for the $t\bar t H$ production cross section is $\sigma(t\bar t H) =
790^{+230}_{-210}$ fb, in agreement with the Standard Model prediction of
$507^{+35}_{-50}$ fb. The combination of this result with other $t\bar t H$
searches from the ATLAS experiment using the Higgs boson decay modes to $b\bar
b$, $\gamma\gamma$ and $ZZ^* \to 4\ell$, has an observed significance of 4.2
standard deviations, compared to an expectation of 3.8 standard deviations.
This provides evidence for the $t\bar t H$ production mode.

25
The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
28
The categories of this paper are: alg-geom
30
The categories of this paper are: q-alg
22
The categories of this paper are: chao-dyn
26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ
13
The categories of this paper are: quant-ph
11
The categories of this paper are: hep-lat
2
The categories of this paper are: math
37
The categories of this paper are: supr-con
27
The categories of this paper are: comp-gas
5
The categories of this paper are: gr-qc
36
The categories of this paper are: cmp-lg
16
The categories of this paper are: stat
10
The categories of this paper are: q-bio