Helical magnetic fields from sphaleron decay and baryogenesis

Craig J. Copi, Francesc Ferrer, Tanmay Vachaspati, Ana Achúcarro

Research output: Contribution to journalArticle

42 Scopus citations


Many models of baryogenesis rely on anomalous particle physics processes to give baryon number violation. By numerically evolving the electroweak equations on a lattice, we show that baryogenesis in these models creates helical cosmic magnetic fields, though the helicity created is smaller than earlier analytical estimates. After a transitory period, electroweak dynamics is found to conserve the Chern-Simons number and the total electromagnetic helicity. We argue that baryogenesis could lead to magnetic fields of nano-Gauss strength today on astrophysical length scales. In addition to being astrophysically relevant, such helical magnetic fields can provide an independent probe of baryogenesis and CP violation in particle physics.

Original languageEnglish (US)
Article number171302
JournalPhysical Review Letters
Issue number17
StatePublished - Oct 24 2008
Externally publishedYes


ASJC Scopus subject areas

  • Physics and Astronomy(all)

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