1 research outputs found
Determining the WIMP mass from a single direct detection experiment, a more detailed study
The energy spectrum of nuclear recoils in Weakly Interacting Massive Particle
(WIMP) direct detection experiments depends on the underlying WIMP mass. We
study how the accuracy with which the WIMP mass could be determined by a single
direct detection experiment depends on the detector configuration and the WIMP
properties. We investigate the effects of varying the underlying WIMP mass and
cross-section, the detector target nucleus, exposure, energy threshold and
maximum energy, the local circular speed and the background event rate and
spectrum. The number of events observed is directly proportional to both the
exposure and the cross-section, therefore these quantities have the greatest
bearing on the accuracy of the WIMP mass determination. The relative
capabilities of different detectors to determine the WIMP mass depend not only
on the WIMP and target masses, but also on their energy thresholds. We find
that the rapid decrease of the nuclear form factor with increasing momentum
transfer which occurs for heavy nuclei, means that heavy nuclei will not
necessarily be able to measure the mass of heavy WIMPs more accurately.
Uncertainty in the local circular speed and non-negligible background would
both lead to systematic errors in the WIMP mass determination. With a single
detector it will be difficult to disentangle a WIMP signal (and the WIMP mass)
from background if the background spectrum has a similar shape to the WIMP
spectrum (i.e. exponential background, or flat background and a heavy WIMP).Comment: 20 pages, 11 figures, version to appear in JCAP, minor changes to
presentatio