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

TL;DR

This paper proposes a dedicated experiment at LHC to detect milli-charged particles produced in proton collisions, aiming to explore new parameter space for particles with very small charge and specific mass ranges.

Contribution

It introduces a novel experimental setup at LHC Point 5 designed to detect milli-charged particles with enhanced sensitivity and minimal interference with existing operations.

Findings

Sensitivity to particles with charge ~10^{-3}e at 1 GeV mass

Sensitivity to particles with charge ~10^{-2}e at 10 GeV mass

Extends the parameter space for small-charge particles above 100 MeV

Abstract

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