  We report a previously unobserved quantum oscillation frequency in YbRh2Si2.
This is the first quantum oscillation that can definitely be assigned to the
larger of the two major sheets of the Fermi surface predicted by band structure
calculations. Previously observed frequencies were interpreted in terms of a
large Fermi surface, which includes the Yb 4f-hole in the Fermi volume, that
has been so strongly spin-split that it closely resembles the small Fermi
surface, which does not include the Yb 4f -hole in the Fermi volume. The new
frequency can also be incorporated into this picture, however there are some
indications that the a need for more advanced energy band calculations.
