Timing-Based Search for Magnetic Monopoles with the NOvA Detector on the Surface

Abstract

We report a search for a magnetic monopole component of the cosmic-ray flux in a 2743-live-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 $8\times 10^{-16}\mathrm{c}{\mathrm{m}}^{-2}{\mathrm{s}}^{-1}\mathrm{s}{\mathrm{r}}^{-1}$ at 90% C.L. for monopole speed $6\times 10^{-4}<\beta <5\times 10^{-3}$ and mass greater than $10^9$ GeV. Because of NOvA's small overburden of 3 meters-water equivalent, this constraint covers a previously unexplored low-mass region.

8 pages, 9 figures