A Letter of Intent to Install a milli-charged Particle Detector at LHC\n P5

Abstract

In this LOI we propose a dedicated experiment that would detect\n"milli-charged" particles produced by pp collisions at LHC Point 5. The\nexperiment would be installed during LS2 in the vestigial drainage gallery\nabove UXC and would not interfere with CMS operations. With 300 fb$^{-1}$ of\nintegrated luminosity, sensitivity to a particle with charge\n$\\mathcal{O}(10^{-3})~e$ can be achieved for masses of $\\mathcal{O}(1)$ GeV,\nand charge $\\mathcal{O}(10^{-2})~e$ for masses of $\\mathcal{O}(10)$ GeV,\ngreatly extending the parameter space explored for particles with small charge\nand masses above 100 MeV.\n