Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Search for long-lived particles decaying into electron or photon pairs
  with the D0 detector   In this Letter we report on a search for long-lived particles that decay into
final states with two electrons or photons. Such long-lived particles arise in
a variety of theoretical models, like hidden valleys and supersymmetry with
gauge-mediated breaking. By precisely reconstructing the direction of the
electromagnetic shower we are able to probe much longer lifetimes than
previously explored. We see no evidence of the existence of such long-lived
particles and interpret this search as a quasi model-independent limit on their
production cross section, as well as a limit on a long-lived fourth generation
quark.

10
The categories of this paper are: q-bio
26
The categories of this paper are: bayes-an
19
The categories of this paper are: eess
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
4
The categories of this paper are: cond-mat
35
The categories of this paper are: mtrl-th
11
The categories of this paper are: hep-lat
24
The categories of this paper are: dg-ga
36
The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
3
The categories of this paper are: physics
23
The categories of this paper are: solv-int
20
The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph