A Search for Boron in Damped Ly{\alpha} Systems
  We present the first systematic study of boron beyond the Local Group. This
analysis is performed on a sample of 30 damped Ly{\alpha} systems (DLAs) with
strong metal-lines, which are expected to trace the interstellar medium of high
z galaxies. We report on two boron detections at > 3{\sigma} significance; one
new detection and one confirmation. The ratios of B/O and, for the first time,
B/S are compared with previous stellar and interstellar measurements in the
Milky Way and Small Magellanic Cloud. The novel comparison with sulphur, which
tracks oxygen's abundance, alleviates the uncertainty associated with stellar
oxygen measurements. For both detections, the inferred B/S ratio is in excess
of the prediction of primary boron production from spallation processes.
Possible sources of contamination are discussed, as well as physical effects
that could impact the observed ratios. However taken at face value, the
implication of these measurements suggest potentially higher cosmic ray fluxes
in DLAs. The prospects for future boron detections in other high redshift DLAs
to confirm our results is also discussed.
