Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Measurement of two-particle correlations in hadronic $e^{+}e^{-}$
  collisions at Belle   The enhancement of charged-particle pairs with large pseudorapidity
difference and small azimuthal angle difference, often referred to as the
``ridge signal'', is a phenomenon widely observed in high multiplicity
proton-proton, proton-ion and deutron-ion collisions, which is not yet fully
understood. In heavy-ion collisions, the hydrodynamic expansion of the
Quark-Gluon Plasma is one of the possible explanations of the origin of the
ridge signal. Measurements in the $e^+e^-$ collision system, without the
complexities introduced by hadron structure in the initial state, can serve as
a complementary probe to examine the formation of a ridge signal. The first
measurement of two-particle angular correlation functions in high multiplicity
$e^+e^-$ collisions at $\sqrt{s}=10.52$ GeV is reported. The hadronic $e^+e^-$
annihilation data collected by the Belle detector at KEKB are used in this
study. Two-particle angular correlation functions are measured over the full
azimuth and large pseudorapidity intervals which are defined by either the
electron beam axis or the event thrust as a function of charged particle
multiplicity. The measurement in the event thrust analysis, with mostly
outgoing quark pairs determining the reference axis, is sensitive to the region
of additional soft gluon emissions. No significant ridge signal is observed
with either coordinates analyses. Near side jet correlations appear to be
absent in the thrust axis analysis. The measurements are compared to
predictions from various event generators and expected to provide new
constraints to the phenomenological models in the low energy regime.

10
The categories of this paper are: q-bio
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
15
The categories of this paper are: nucl-ex
24
The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
2
The categories of this paper are: math
14
The categories of this paper are: math-ph
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
6
The categories of this paper are: astro-ph
11
The categories of this paper are: hep-lat