Direct Observation of Proton Emission in ^{11}Be

Area of Science:

• Nuclear Physics
• Radioactive Decay Studies
• Exotic Nuclei Research

Background:

• Beta-minus-proton-plus (β⁻p⁺) decay is a rare nuclear process.
• Previous theoretical models did not fully explain observed decay patterns.
• Understanding exotic nuclei like Beryllium-11 (¹¹Be) is crucial for nuclear structure theories.

Purpose of the Study:

• To directly observe and characterize the β⁻p⁺ decay of ¹¹Be.
• To measure the energy distribution of emitted protons.
• To compare experimental results with existing theoretical predictions.

Main Methods:

• Utilized a prototype Active Target Time Projection Chamber (AT-TPC).
• Conducted experiments at the ISAC-TRIUMF facility.
• Directly measured emitted protons and their energy spectra.

Main Results:

• Successfully observed the β⁻p⁺ decay of ¹¹Be for the first time.
• Measured a β⁻p⁺ branching ratio orders of magnitude higher than theoretical predictions.
• The experimental data suggests the presence of a narrow resonance in Boron-11 (¹¹B) above the proton separation energy.

Conclusions:

• The observed β⁻p⁺ decay of ¹¹Be provides critical new data for nuclear physics.
• The unexpectedly high branching ratio indicates limitations in current theoretical models.
• A newly identified resonance in ¹¹B likely explains the enhanced decay probability.