Energy frontier lepton-hadron colliders, vector-like quarks and leptons, preons and so on

Abstract

First of all, an importance of the LHC and FCC based energy frontier lepton-hadron and photon-hadron colliders is emphasised. Then arguments favoring existence of new heavy isosinglet down-type quarks and vector-like isosinglet or isodoublet leptons are presented, following by historical arguments favoring new (preonic) level of matter. The importance of Super-Charm factory and GeV energy proton linac for Turkey national road map is argued. Finally, several recommendations for ESPP2020 are suggested.