Clusters and higher moments of proton number fluctuations

Production of deuterons by coalescence has an important influence on the moments of the observed proton number distribution. Therefore, this effect must be taken into account when physics conclusions about baryon number fluctuation are drawn from the measurement of proton number fluctuations. We also show that a measurement of the third and fourth moments of the deuteron number distribution would allow to distinguish whether deuterons are produced statistically or by coalescence.