Beam Dynamics Studies for Uniform (Hollow) Bunches or Super-bunches in the LHC: Beam-beam effects, Electron Cloud, Longitudinal Dynamics, and Intrabeam Scattering

Possible upgrade scenarios for the Large Hadron Collider (LHC) comprise the operation with either uniform (hollow) bunches or long super-bunches. We discuss the respective merits of these approaches with regard to beam-beam effects, electron cloud, and luminosity. Next, we compare the usual scheme of alternating collisions in the horizontal and vertical plane at two interaction points with that of inclined hybrid collisions at 45° and 135°. We then study the longitudinal dynamics for a barrier bucket rf system, including the effect of synchrotron radiation, and, finally, discuss the intrabeam scattering for both Gaussian and uniform bunches (or super-bunches).