  An unexpected result at the RHIC and the LHC is the observation that
high-multiplicity hadronic events in heavy-ion and proton-proton collisions are
distributed as two "ridges", approximately flat in rapidity and opposite in
azimuthal angle. We propose that the origin of these events is due to the
inelastic collisions of aligned gluonic flux tubes that underly the color
confinement of the quarks in each proton. We predict that high-multiplicity
hadronic ridges will also be produced in the high energy photon-photon
collisions accessible at the LHC in ultra-peripheral proton-proton collisions
or at a high energy electron-positron collider. We also note the orientation of
the flux tubes between the quark and antiquark of each high energy photon will
be correlated with the plane of the scattered proton or lepton. Thus hadron
production and ridge formation can be controlled in a novel way at the LHC by
observing the azimuthal correlations of the scattering planes of the
ultra-peripheral protons with the orientation of the produced ridges.
Photon-photon collisions can thus illuminate the fundamental physics underlying
the ridge effect and the physics of color confinement in QCD.
