First Observation of (Anti)Deuterons in DIS

Abstract

First observation of (anti)deuterons in deep inelastic ep scattering (DIS) measured with the ZEUS detector at HERA is reported. The production rate of deuterons is higher than that of antideuterons. However, no asymmetry in the production rate of protons and antiprotons was found. The (anti)deuteron yield is approximately three orders of magnitude smaller than that of (anti)protons, which is consistent with the world measurements.