We present the first results in the search for relativistic magnetic monopoles with the IceCube detector, a subsurface neutrino telescope located in the South Polar ice cap containing a volume of $1{\mathrm{km}}^3$. This analysis searches data taken on the partially completed detector during 2007 when roughly $0.2{\mathrm{km}}^3$ of ice was instrumented. The lack of candidate events leads to an upper limit on the flux of relativistic magnetic monopoles of ${\Phi }_{90\%\mathrm{C}.\mathrm{L}.}\sim 3\times {10}^{-18}{\mathrm{cm}}^{-2}{\mathrm{sr}}^{-1}{\mathrm{s}}^{-1}$ for $\beta \ge 0.8$. This is a factor of 4 improvement over the previous best experimental flux limits up to a Lorentz boost $\gamma$ below ${10}^7$. This result is then interpreted for a wide range of mass and kinetic energy values.

• Received 27 August 2012

DOI:https://doi.org/10.1103/PhysRevD.87.022001