Resonance state in $^{7}$H

The existence of the {sup 7}H nuclear system was investigated via a one-proton transfer reaction with a {sup 8}He beam at 15.4A MeV and a {sup 12}C gas target. The experimental setup was based on the active-target MAYA which allowed a complete reconstruction of the reaction kinematics. The existence of the {sup 7}H was confirmed with the identification of seven events where the system was formed with a resonance energy of 0.57{sub -0.21}{sup +0.42} MeV above the {sup 3}H+4n threshold and a resonance width of 0.09{sub -0.06}{sup +0.94} MeV. This study represents an unambiguous proof of the existence of the most neutron-proton unbalanced system presently found.