Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Coherent and incoherent pair creation by a photon in oriented single
  crystal   The new approach is developed for study of electron-positron pair production
by a photon in oriented single crystal. It permits indivisible consideration of
both coherent and incoherent mechanisms of pair creation and includes the
action of field of axis (or plane) as well as the multiple scattering of
particles of the created pair (the Landau-Pomeranchuk-Migdal (LPM) effect).
  From obtained integral probability of pair creation, it follows that multiple
scattering appears only for relatively low energy of photon, while at higher
photon energy the field action excludes the LPM effect. The found results agree
quite satisfactory with recent CERN experiment.

30
The categories of this paper are: q-alg
18
The categories of this paper are: econ
3
The categories of this paper are: physics
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
28
The categories of this paper are: alg-geom
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
19
The categories of this paper are: eess
26
The categories of this paper are: bayes-an
29
The categories of this paper are: funct-an