Search for Slow Magnetic Monopoles with the NOvA Detector on the Surface

TL;DR

This study used the NOvA detector to search for slow magnetic monopoles in cosmic rays, setting new upper limits on their flux in a previously unexplored low-mass range.

Contribution

First search for slow magnetic monopoles with the NOvA detector, establishing new flux limits in the low-mass, low-velocity region of parameter space.

Findings

No monopole events detected.

Set upper flux limit of 2×10⁻¹⁴ cm⁻² s⁻¹ sr⁻¹.

Covered a previously unexplored low-mass monopole region.

Abstract

We report a search for a magnetic monopole component of the cosmic-ray flux in a 95-day exposure of the NOvA experiment's Far Detector, a 14 kt segmented liquid scintillator detector designed primarily to observe GeV-scale electron neutrinos. No events consistent with monopoles were observed, setting an upper limit on the flux of $2\times 10^{-14} \mathrm{cm^{-2}s^{-1}sr^{-1}}$ at 90% C.L. for monopole speed $6\times 10^{-4} < \beta < 5\times 10^{-3}$ and mass greater than $5\times 10^{8}$ GeV. Because of NOvA's small overburden of 3 meters-water equivalent, this constraint covers a previously unexplored low-mass region.