Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Two Photon Physics in pp and AA Collisions   In central collisions at relativistic heavy ion colliders like the
Relativistic Heavy Ion Collider RHIC/Brookhaven and the Large Hadron Collider
LHC (in its heavy ion mode) at CERN/Geneva, one aims at detecting a new form of
hadronic matter - the Quark Gluon Plasma. We discuss here a complementary
aspect of these collisions, the very peripheral ones. Due to coherence, there
are strong electromagnetic fields of short duration in such collisions. They
give rise to photon-photon and photon-nucleus collisions with high flux up to
an invariant mass region hitherto unexplored experimentally. After a general
survey photon-photon luminosities in relativistic heavy ion collisions are
discussed. Special care is taken to include the effects of strong interactions
and nuclear size. Then photon-photon physics at various gamma-gamma-invariant
mass scales is discussed. The region of several GeV, relevant for RHIC is
dominated by QCD phenomena (meson and vector meson pair production). Invariant
masses of up to about 100 GeV can be reached at LHC, and the potential for new
physics is discussed. Photonuclear reactions and other important background
effects, especially diffractive processes are also discussed. Lepton-pair
production, especially electron-positron pair production is copious. Due to the
strong fields there will be new phenomena, especially multiple e+e- pair
production.

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The categories of this paper are: chem-ph
1
The categories of this paper are: cs
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The categories of this paper are: q-fin
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-th
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The categories of this paper are: alg-geom
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The categories of this paper are: bayes-an
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The categories of this paper are: eess
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The categories of this paper are: nlin
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The categories of this paper are: hep-ex
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The categories of this paper are: quant-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: comp-gas
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The categories of this paper are: physics
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The categories of this paper are: adap-org
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The categories of this paper are: solv-int