Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: First Combined Study on LIV from Observations of Energy-dependent Time
  Delays from Multiple-type Gamma-ray Sources -- Part I. Motivation, Method
  Description and Validation through Simulations of H.E.S.S., MAGIC and VERITAS
  Datasets   Gamma-ray astronomy has become one of the main experimental ways to test the
modified dispersion relations (MDRs) of photons in vacuum, obtained in some
attempts to formulate a theory of Quantum Gravity. The MDRs in use imply time
delays which depend on the energy, and which increase with distance following
some function of redshift. The use of transient, or variable, distant and
highly energetic sources, already allows us to set stringent limits on the
energy scale related to this phenomenon, usually thought to be of the order of
the Planck energy, but robust conclusions on the existence of MDR-related
propagation effects still require the analysis of a large population of
sources.
  In order to gather the biggest sample of sources possible for MDR searches at
teraelectronvolt energies, the H.E.S.S., MAGIC and VERITAS collaborations
enacted a joint task force to combine all their relevant data to constrain the
Quantum Gravity energy scale. In the present article, the likelihood method
used, to combine the data and provide a common limit, is described in detail
and tested through simulations of recorded data sets for a gamma-ray burst,
three flaring active galactic nuclei and two pulsars. Statistical and
systematic errors are assessed and included in the likelihood as nuisance
parameters. In addition, a comparison of two different formalisms for distance
dependence of the time lags is performed for the first time. In a second
article, to appear later, the method will be applied on all relevant data from
the three experiments.

10
The categories of this paper are: q-bio
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The categories of this paper are: nlin
4
The categories of this paper are: cond-mat
13
The categories of this paper are: quant-ph
18
The categories of this paper are: econ
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The categories of this paper are: eess
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
8
The categories of this paper are: hep-ex
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The categories of this paper are: solv-int
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The categories of this paper are: alg-geom
32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
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The categories of this paper are: hep-lat
1
The categories of this paper are: cs
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The categories of this paper are: nucl-ex