A Measurement of the Virtual Photon Structure Function

The structure function of a virtual photon, representing the physics of the hard scattering of an electron off a massive photon target resulting in a hadronic final state, has been measured in the kinematic range 1.5 {le} Q{sup 2} {le} 5.5 GeV{sup 2}, 0.1 {le} P{sup 2} {le} 1.5 GeV{sup 2} and 2 {le} W {le} 20 GeV. The measurement was done using the TPC/Two-Gamma detector facility and employs a heretofore unique method to determine the W of the final state by using information from both the visible mass of the final state as well as the mass reconstructed from the two lepton tags. The results are compared to a variety of models, and are found to be consistent with an incoherent sum of the QPM and VDM models.