Measurement of (anti)deuteron and (anti)proton production in deep inealstic ep scattering with ZEUS at HERA 

The first observation of (anti)deuterons in deep inelastic ep scattering
was made with ZEUS at HERA at centre-of-mass energies of 300 and 318 GeV 
using an integrated luminosity of 120 pb-1. The measurement was performed 
in the central rapidity region for transverse momenta per unit of mass 
in the range 0.3 < pT/M < 0.7. The production rates were extracted 
and interpreted in terms of the coalescence model. The (anti)deuteron 
production yield is smaller than the (anti)proton yield by approximately 
three orders ofmagnitude, consistent with other measurements.