Determination of upper and lower limits combining different experimental results

This paper discusses how to combine different experimental results in order to obtain upper or lower limits of physical quantities in the case of null experiments. Reanalyzing some published results, half-life limits for p → e+π0, p → νK+, and for the 76Ge ββ(0ν)-decay to the ground state of 76Se were determined as 5.7 × 1032, 1.4 × 1032 and 2.5 × 1024 yr, respectively, at 90% Confidence Level. The Bayesian approach is adopted using a step function as the prior-probability density function of the decay constant.