Beyond the Standard Model Physics at the HL-LHC and HE-LHC
This is the third out of five chapters of the final report [1] of the Workshop on Physics at HL-LHC, and perspectives on HE-LHC [2]. It is devoted to the study of the potential, in the search for Beyond the Standard Model (BSM) physics, of the High Luminosity (HL) phase of the LHC, defined as $3~mathrmab^-1$ of data taken at a centre-of-mass energy of $14~mathrmTeV$, and of a possible future upgrade, the High Energy (HE) LHC, defined as $15~mathrmab^-1$ of data at a centre-of-mass energy of $27~mathrmTeV$.