  When analyzing the content of Physics Letter B (PLB) web pages, one goal was
to separate articles from particle physics(HEP) and nuclear physics(NP). PLB
contains information about the subject area of an article: Astrophysics and
Cosmology, Experiments, Phenomenology or Theory. Those subject areas have been
used since 2004. To extend those areas to earlier dates and try to separate HEP
and NP publications, the idea was to use the information on the arXiv to
accomplish this, by correlating a publication in PLB with a publication in one
of the different arXiv repositories for particle, nuclear or astrophysics. The
arXiv articles go back to at least 1995. When building the correlation between
an arXiv article and each PLB article, it was found that many PLB articles do
not have an existing reference in an arXiv article. Given that, the same
analysis was performed using particle, nuclear and astro physics publications
in Physical Review Letters (PRL). A similar result was obtained, but for a much
shorter period of time. Finally, a title match was performed between the two
journals and the arXiv, to see whether the preprint version of the journal
article existed on the arXiv at all. They do, but without a journal reference.
