Search for Millicharged Particles in Proton-Proton Collisions at sqrt[s]=13.6  TeV

Area of Science:

• High Energy Physics
• Particle Physics
• Collider Physics

Background:

• The Standard Model of particle physics does not predict particles with charges significantly smaller than the electron charge.
• Searches for such exotic particles are crucial for exploring physics beyond the Standard Model.

Purpose of the Study:

• To search for new elementary particles with fractional electric charges (≤0.24 e).
• To set new experimental constraints on the mass and charge of these hypothetical particles.

Main Methods:

• Analysis of proton-proton collision data collected by the CERN Large Hadron Collider during Run 3 (2023-24).
• Utilized the completed Run 3 milliQan detector to identify potential signals of low-charge particles.
• Data corresponds to an integrated luminosity of 124.7 fb⁻¹ at a center-of-mass energy of 13.6 TeV.

Main Results:

• No evidence for the production of particles with charges ≤0.24 e was found.
• The analysis established the most stringent experimental constraints to date for particles with charges ≤0.24 e and masses ≥0.45 GeV.

Conclusions:

• The results significantly narrow the parameter space for the existence of light, low-charge elementary particles.
• This search contributes to the ongoing quest for physics beyond the Standard Model at the energy frontier.