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Monopole-Fermion Scattering and the Solution to the Semiton–Unitarity Puzzle

Vazha Loladze1,* and Takemichi Okui2,3,†

  • *Contact author: vazha.loladze@physics.ox.ac.uk
  • †Contact author: tokui@fsu.edu
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Phys. Rev. Lett. 134, 051602 – Published 6 February, 2025

DOI: https://doi.org/10.1103/PhysRevLett.134.051602

Abstract

We study Polchinski’s “fermion-rotor system” as an accurate description of charged Weyl fermions scattering on a magnetic monopole core in the limit of zero gauge coupling. Traditionally it was thought such scattering could lead to fractional particle numbers (“semitons”). By direct calculations we show those semitonic processes are in fact free propagation, facilitated by composite fermion-rotor operators interpolating the “forbidden” states, effectively “recovering” both ingoing and outgoing states in every lowest partial wave. Nonsemitonic Callan-Rubakov processes are unchanged.

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synopsis

No Need for Fractional Particles

Published 6 February, 2025

The scattering of a charged particle off a magnetic monopole does not imply the existence of fractional particle numbers, theorists say.

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References (27)

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  20. SU(4)F-violating corrections to this result by continuous parameters, which could be imagined as small as we wish, would not fundamentally solve the problem, so by ignoring SM couplings we are focusing on the heart of the puzzle.

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Outline

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Phys. Rev. Lett. 134, 051602– Published 6 February, 2025
  • Received 29 August 2024
  • Revised 17 November 2024
  • Accepted 27 November 2024
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