Deuteron production in p-Be interactions at 450 GeV/c and the coalescing model

The analysis of the deuteron production in p--Be interactions at 450 GeV/c taken by the NA56/SPY experiment at CERN SPS is presented. In the framework of the coalescence model, the coalescence factor $\kappa$ is determined as $(0.79 \pm 0.05 \pm 0.13) \times 10^{-2}$. Our results disfavour the hypothesis that coalescence be the dominant mechanism for deuteron production in $p+Be$ interactions at low $p_T$.