Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cross section normalization in proton-proton collisions at $\sqrt{s}$ =
  2.76 TeV and 7 TeV, with ALICE at LHC   Measurements of the cross sections of the reference processes seen by the
ALICE trigger system were obtained based on beam properties measured from van
der Meer scans. The measurements are essential for absolute cross section
determinations of physics processes.
  The paper focuses on instrumental and technical aspects of detectors and
accelerators, including a description of the extraction of beam properties from
the van der Meer scan. As a result, cross sections of reference processes seen
by the ALICE trigger system are given for proton-proton collisions at two
energies; $\sqrt{s}$=2.76 TeV and 7 TeV, together with systematic uncertainties
originating from beam intensity measurements and other detector effects.
Consistency checks were performed by comparing to data from other experiments
in LHC.

17
The categories of this paper are: q-fin
0
The categories of this paper are: hep-ph
13
The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th
6
The categories of this paper are: astro-ph
25
The categories of this paper are: patt-sol
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
4
The categories of this paper are: cond-mat
5
The categories of this paper are: gr-qc
7
The categories of this paper are: hep-th