`Double parton scattering'

Abstract : Double parton scattering (DPS) -- the process in which two
distinct pairs of partons hard scatter in an individual proton-proton
collision represents an important background to certain Higgs and new
physics signals, and can reveal novel information about the proton
structure. I will show that a long-established framework for
describing the total DPS cross section appears to contain some
unsatisfactory features, examine the various types of graph that can
potentially contribute to the DPS cross section, and suggest an
alternative formula for the DPS cross section (although I will explain
that there still appear to be some remaining issues with this
formula). I will also discuss interference and correlated parton
contributions to DPS, and the Sudakov suppression of colour
interference contributions.