Evidence for Heavy Hyperhydrogen _{Λ}^{6}H

Evidence for the neutron-rich hypernucleus 60H is presented from the FINUDA experiment at DA NE, Frascati, studying ð%þ; %Þ pairs in coincidence from the K þ 6Li ! 6 H þ %þ production reaction stop 0 followed by 60H ! 6He þ % weak decay. The production rate of 60H undergoing this two-body % decay is determined to be ð2:9 ` 2:0Þ 106=K . Its binding energy, evaluated jointly from production and stop decay, is B0ð60HÞ 1⁄4 ð4:0 ` 1:1Þ MeV with respect to 5H þ 0. A systematic difference of ð0:98 ` 0:74Þ MeV between B0 values derived separately from decay and from production is tentatively assigned to the 60H 0þg:s: ! 1þ excitation