Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A model for leptogenesis at the TeV scale   We consider the mechanism of thermal leptogenesis at the TeV scale in the
context of an extension of the Standard Model with 4 generations and the
inclusion of four right-handed Majorana neutrinos. We obtain a value for the
baryon asymmetry of the
  Universe in accordance with observations by solving the full set of coupled
Boltzmann equations for this model.

33
The categories of this paper are: plasm-ph
34
The categories of this paper are: chem-ph
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
23
The categories of this paper are: solv-int
37
The categories of this paper are: supr-con
11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex
19
The categories of this paper are: eess
6
The categories of this paper are: astro-ph
4
The categories of this paper are: cond-mat
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph