Energy Loss of Slowly Moving Magnetic Monopoles in Matter

Abstract

The cross section for exciting simple atoms by slowly moving magnetic monopoles is calculated. Including the effects of the monopole magnetic field on the atomic energy levels, an energy loss per unit density is obtained that is much larger than previous studies. For helium $(\frac{1}{\ensuremath{\rho}})\frac{\mathrm{dE}}{\mathrm{dx}}=15(\frac{\ensuremath{\beta}}{{10}^{\ensuremath{-}4}}){[1\ensuremath{-}{(9.29\ifmmode\times\else\texttimes\fi{}\frac{{10}^{\ensuremath{-}5}}{\ensuremath{\beta}})}^{2}]}^{\frac{3}{2}}$ MeV ${\mathrm{cm}}^{2}$/g for $\ensuremath{\beta}$ in the range ${10}^{\ensuremath{-}4}$ to ${10}^{\ensuremath{-}3}$. The possibility of using helium as a monopole detector is discussed.