Book Description

The inclusive inelastic electron scattering o the proton was measured at five different beam energies 1.5, 2.5, 4.0, 4.2 and 4.4 GeV. The data were taken, during February-March 1999, on a liquid hydrogen target with the CLAS detector installed in Hall-B of the Thomas Jefferson National Accelerator Facility (TJNAF). The obtained high statistics and high precision data appear to be in good agreement with previously measured world data and permit to integrate experimental values of F2 over x at fixed Q2 , allowing for the first time the evaluation of its experimental moments at low and moderate values of Q2 . In a combined analysis of CLAS and world data, the Q2-evolution of the experimental moments was explored in the range from 0.3 up to 100 GeV2 . This offered a unique possibility to trace changes of the proton structure function from hard DIS down to the non-perturbative regime through the transition region, which is of particular interest for the TJNAF physics program. The obtained experimental moments allowed to perform a separation between the leading twist, calculable in the framework of the perturbative QCD (pQCD), and higher twists, treated effectively. A comparison with theoretical predictions based either on lattice QCD simulations or obtained within models of the nucleon structure may represent an important test of our understanding of the nucleon structure as observed at large wavelengths.