On influence of experimental resolution on the statistical significance of a signal: implication for pentaquark searches

An analytical relationship between the statistical significance of an observed signal and the signal width in case of a large background was obtained. It can help to explain why high-energy experiments may have different conclusions on the existence of new particles. We illustrate our approach using the experimental data on searches for the Theta+(1530) pentaquark state. The obtained relationship is also useful for planning of future experiments designed to search for signals of new particles in invariant-mass distributions.