HERA-BASED GAMMA-P COLLIDER - LUMINOSITY AND PHYSICS(LC)

We discuss the possibility of constructing a linac ring type ep collid er and a gamma p collider based on it at DESY, namely the HERA+LC prop osal. Using the parameters of the proton ring of HERA and those of the proposed linear e(+)e(-) collider (LC), we expect a luminosity of L(g amma p) = 1-2 X 10(31) cm(-2)s(-1), due to reasonable improvement of t he proton beam. In a gamma p collider, the high energy gamma beam is p roduced by the Compton backscattering of laser photons off the electro n beam from the linear accelerator. In the case of the opposite choice of laser photon and electron beam helicities, the luminosity of gamma p collisions still exceeds 10(31) cm(-2)s(-1) up to a distance of 12 m between the conversion region and the collision point. We examine th e physics research program for the HERA+LC gamma p collider proposal. The search for supersymmetric partners, leptoquark production and heav y quark investigations are considered in detail. The capacity of HERALC surpasses that of HERA and is comparable with the LC. Polarization facilities of the gamma and proton beams, and the clearer background c ompared to the hadron colliders, are stated as additional advantages o f the proposed gamma p collider.