Measurement of the hadronic photon structure function F(2)(gamma) with the L3 detector at LEP

The photon is one of the basic components of our present understanding of elementary particles and their interactions. The theory of Quantum Electrodynamics describes this object as being the mediator of the electromagnetic force between charged particles. Contrary to earlier assumptions the photon turns out to have a "structure" due to quantum fluctuations into fermion anti-fermion pairs that can further interact with other particles. In this case the photon reveals its structure. The structure of the photon can be described by the concept of photon structure functions, which are studied at high energy accelerators like the Large Electron Positron Collider at the European Center for Particle Physics. With the large amount of data (L = 608 pb-1) collected with the L3 detector at center-of-mass energies 189 GeV < s < 209 GeV and the analysis method used in this dissertation, a measurement of the hadronic structure function F2gamma (x,Q2)/alpha is obtained with better precision than previous measurements. The evolution of F2 gamma/alpha as a function of x and Q2 is studied in the 11 GeV2 < Q2 < 34 GeV2 and 0.006 < x < 0.556 intervals. Due to the precision of this measurement it is possible for the first time to demonstrate that the results of the higher-order GRV parametrization of the structure function are in good agreement with the data and give a correct description of the physical processes involved