Development of the Gaseous Antiparticle Spectrometer for Space-based Antimatter Detection

We report progress in developing a novel antimatter detection scheme. The gaseous antiparticle spectrometer (GAPS) identifies antimatter through the characteristic X-rays emitted by antimatter when it forms exotic atoms in gases. The approach provides large area and field of view, and excellent background rejection capability. If the GAPS concept is successfully demonstrated, then it would be an ideal candidate for space-based, indirect dark matter searches. GAPS can detect antideuterons produced in neutralino annihilations. A modest GAPS experiment can detect the neutralino for all minimal SUSY models in which the neutralino mass is in the ∼ 50–350 GeV mass range. Underground searches, by contrast, are only sensitive to about 1/2 the SUSY parameter space in this mass range.