Excited-state hydroxyl maser polarimetry: Who ate all the {\pi}s?
  We present polarimetric maser observations with the Australia Telescope
Compact Array (ATCA) of excited-state hydroxyl (OH) masers. We observed 30
fields of OH masers in full Stokes polarization with the Compact Array
Broadband Backend (CABB) at both the 6030 and 6035 MHz excited-state OH
transitions, and the 6668-MHz methanol maser transition, detecting 70 sites of
maser emission. Amongst the OH we found 112 Zeeman pairs, of which 18 exhibited
candidate {\pi} components. This is the largest single full polarimetric study
of multiple sites of star formation for these frequencies, and the rate of 16%
{\pi} components clearly indicates the {\pi} component exists, and is
comparable to the percentage recently found for ground-state transitions. This
significant percentage of {\pi} components, with consistent proportions at both
ground- and excited-state transitions, argues against Faraday rotation
suppressing the {\pi} component emission. Our simultaneous observations of
methanol found the expected low level of polarisation, with no circular
detected, and linear only found at the less than or equal to 10% level for the
brightest sources.
