# Stuff From PhD Proposal

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Deep inelastic scattering (DIS) of electrons by hadrons is a powerful tool for understanding the structure of the nucleon. When the momentum transferred to the target hadron is larger than the hadron mass, the inelastic scattering can be considered as the incoherent sum of the elastic scattering off the hadron constituents.

The way to think of this is that the electron hits the target with a photon whose momentum is the amount of momentum transfered.  If the photons wavelength is a lot less than the size of the target (1 fermi or 200 Mev) then you see the constituents


In the quark parton model, a proton is described in terms of fractionally charged constituents called up (u) and down (d) quarks. QCD extends the list of constituents to include antiquarks with all constituents interacting through the exchange of neutrally charged gluons. The QCD picture of a nucleon in terms of three valence quarks and a sea of quark-antiquark pairs has been supported by several deep inelastic scattering experiments [ CERN, SLAC, HERMES]