Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Low Polonium Field of Borexino and its significance for the CNO
  neutrino detection   Borexino is a liquid scintillator detector located at the Laboratori
Nazionale del Gran Sasso, Italy with the main goal to measure solar neutrinos.
The experiment recently provided the first direct experimental evidence of
CNO-cycle neutrinos in the Sun, rejecting the no-CNO signal hypothesis with a
significance greater than 5$\sigma$ at 99\%C.L. The intrinsic $^{210}$Bi is an
important background for this analysis due to its similar spectral shape to
that of CNO neutrinos. $^{210}$Bi can be measured through its daughter
$^{210}$Po which can be distinguished through an event-by-event basis via pulse
shape discrimination. However, this required reducing the convective motions in
the scintillator that brought additional $^{210}$Po from peripheral sources.
This was made possible through the thermal insulation and stabilization
campaign performed between 2015 and 2016. This article will explain the
strategy and the different methods performed to extract the $^{210}$Bi upper
limit in Phase-III (Jul 2016- Feb 2020) of the experiment through the analysis
of $^{210}$Po in the cleanest region of the detector called the Low Polonium
Field.

37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
13
The categories of this paper are: quant-ph
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
36
The categories of this paper are: cmp-lg
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th
20
The categories of this paper are: acc-phys
22
The categories of this paper are: chao-dyn
23
The categories of this paper are: solv-int
19
The categories of this paper are: eess
27
The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio
11
The categories of this paper are: hep-lat