LHC and VLHC based lepton-hadron colliders: Comparison of e-ring with e-linac

The lepton-hadron colliders with center of mass energy higher than 1 TeV are necessarly both to clarify the nature of strong interactions and for adequate interpretation of experimental data from Large Hadron Collider (LHC). The addition of electron ring might cause a lot of technical problems in LHC and VLHC tunnels. As shown in thesis, Linacs will give opportunity to obtain the same electron beam energy with much shorter lengths. Today, there are two realistic projects, namely, QCD Explorer and LHeC. Both QCD-E and LHeC will give opportunity to achieve sufficiently high luminosity to explore crucial aspects of the strong interactions. It is shown that QCD-E a number of advantages. The main goal of both QCD-E and LHeC projects is to clarify fundamental aspects of strong interactions. Their potential for the BSM physics search is restricted by center of mass energy. Therefore, very high luminosity is not so important. The pair production of heavy quarks for QCD-E have been studied and the significance of this process for small x region has shown. Key Words : QCD, LHC, VLHC, lepton hadron colliders