Monopole heat

Abstract

The most stringent astrophysical limit on the flux of superheavy magnetic monopoles is based on the energy released when monopoles captured by a neutron star catalyse nucleon decay within the neutron star, and is: F_G≲10⁻²² cm⁻² sr⁻¹ s⁻¹. This, and other astrophysical bounds, are bounds on the average flux of monopoles in the Galaxy, not on the local flux of monopoles. Dimopoulos et al.¹ have pointed out that the local flux could be many orders-of-magnitude larger than the average flux. Monopoles moving more slowly than about 3×10⁻⁵ c (10¹⁶ GeV m⁻¹) are stopped in the Earth. Inside the Earth they catalyse nucleon decay, resulting in the release of heat. A bound on the local flux of monopoles moving more slowly than 3 × 10⁻⁵ c (10¹⁶ GeV m⁻¹), F_⊕≲10⁻²¹ cm⁻²sr⁻¹ s⁻¹, is derived here by requiring the energy released to be less than the measured heat flow at the surface of the Earth. Similar arguments are used to derive a bound on the flux of monopoles at Jupiter moving more slowly than 10⁻³c (10¹⁶ GeV m⁻¹), F_J≲10⁻¹⁸ cm⁻² sr⁻¹ s⁻¹.