Resonance state in 7H

Area of Science:

• Nuclear Physics
• Exotic Nuclear Systems
• Nuclear Reactions

Background:

• Investigating exotic nuclear systems pushes the boundaries of our understanding of nuclear forces.
• The seven hydrogen (7H) system, with its extreme neutron-to-proton ratio, has been a subject of theoretical interest.
• Previous experimental evidence for such highly asymmetric systems has been limited.

Purpose of the Study:

• To experimentally investigate the existence of the seven hydrogen (7H) nuclear system.
• To characterize the properties of the 7H system, including its resonance energy and width.
• To confirm the formation of the most neutron-proton unbalanced system observed to date.

Main Methods:

• Utilized a one-proton transfer reaction employing a helium-8 (8He) beam at 15.4A MeV.
• Employed the active-target MAYA detector system for complete reaction kinematics reconstruction.
• Analyzed experimental data to identify events corresponding to the formation of the 7H system.

Main Results:

• Confirmed the existence of the 7H nuclear system through the identification of seven distinct events.
• Determined the resonance energy of the 7H system to be 0.57 MeV above the 3H+4n threshold.
• Measured the resonance width of the 7H system to be 0.09 MeV.

Conclusions:

• The study provides unambiguous experimental proof for the existence of the 7H nuclear system.
• The 7H system represents the most neutron-proton unbalanced nuclear system discovered to date.
• This finding contributes significantly to the understanding of nuclear stability limits and the behavior of exotic nuclei.