Leptogenesis and Primordial Magnetic Fields
  The anomalous conversion of leptons into baryons during leptogenesis is shown
to produce a right-handed helical magnetic field; in contrast, the magnetic
field produced during electroweak baryogenesis is known to be left-handed. If
the cosmological medium is turbulent, the magnetic field evolves to have a
present day coherence scale and field strength that are of astrophysical
interest. Observations of the amplitude, coherence scale, and helicity of the
intergalactic magnetic field promise to provide a powerful probe of physics
beyond the Standard Model and the very early universe.
