Total branching ratio of the K^-two-nucleon absorption in ¹²C

This work is a critical re-analysis of the results obtained by the AMADEUS collaboration, concerning the measurement of the K- multi-nucleon absorption reactions, on a 12C target, in the Λp final state (Del Grande et al 2019 Eur. Phys. J. C 79, 190). We show that a good estimate of the K- two-nucleon absorption total branching ratio can be extracted, given that the measured final state interactions and conversion reactions contain information on almost all the remaining hyperon-nucleon final state combinations. The main contribution to the total branching ratio of the K- two-nucleon absorption in Carbon is extracted from the measured ratios and is found to be (16.1 ± 2.9(stat.)+4.3-5.5 (syst.))%, which is in agreement with recent theoretical predictions. The missing contribution, from those few channels for which a Λp pair could not be detected in the final state of the interaction, is also estimated combining both the measured branching ratios and the available theoretical information, and amounts to (5.5 ± 0.1(stat.)+1.0-0.9(syst.))%. All together the total branching ratio of the K- two-nucleon absorption in Carbon is found to be (21.6 ± 2.9(stat.)+4.4-5.6}(syst.))%.