Monopoles Entangle Fermions

TL;DR

This paper elucidates the scattering process of a positron with a GUT monopole, revealing an entangled final state of quarks and gauge field angular momentum, with implications for understanding monopole-fermion interactions.

Contribution

It provides a detailed analysis of monopole-fermion scattering using on-shell amplitudes, uncovering entangled quark states and gauge field angular momentum conservation, extending previous theoretical models.

Findings

Final state includes entangled quarks and gauge field angular momentum.

Cross section comparable to the Rubakov-Callan effect, suppressed by QCD scale.

Entanglement requires more than two dimensions, not visible in simplified models.

Abstract

We resolve the decades old mystery of what happens when a positron scatters off a minimal GUT monopole in an s-wave, first discussed by Callan in 1983. Using the language of on-shell amplitudes and pairwise helicity we show that the final state contains two up quarks and a down quark entangled with angular momentum stored in the gauge fields, which is the only particle final state that satisfies angular momentum and gauge charge conservation. The cross section for this process is as large as in the original Rubakov-Callan effect, only suppressed by the QCD scale. The final state we find cannot be seen in Callan's truncated 2D theory, since our entanglement requires more than 2 dimensions.