SCEP: a Cosmic Magnetic Monopole Search Experiment

Abstract

Magnetic monopole is a well-motivated class of beyond-Standard-Model particles that could provide insights into the long-standing puzzle of the quantization of electric charge. These hypothetical particles are likely to be super heavy ($\sim$10$^{15}$ GeV) and be produced in the very early stages of the Universe's evolution. We propose a novel detection scenario for the search of such cosmic magnetic monopoles, utilizing a hybrid approach that combines radio-frequency atomic magnetometers and plastic scintillators. Such setup allows for the collection of both the induction and scintillation signals generated by the passage of a magnetic monopole, which provides acceptance to the magnetic monopoles with their velocities larger than about 10$^{-6}$ light speed (assuming a signal-to-noise ratio of $\sim$4) and their masses larger than approximately 10$^7$ GeV (at $\beta\sim10^{-3}$). The proposed detector design has the potential to scale up to large area, enabling the exploration of the parameter space of the cosmic magnetic monopole beyond the current experimental and astrophysical constraints. It is estimated that such detector can reach current most stringent limits of the flux set by previous searches, with a signal-to-noise ratio of the induction signal larger than about 4.5, assuming an effective exposure being 20000 year$\cdot$m$^2$ and coil layer of 3.