Phase-Variation Ramsey Spectroscopy of the 2^{3}S_{1}→ 2^{3}P_{2} Interval in Positronium

Area of Science:

• Atomic Physics
• Quantum Electrodynamics (QED)
• Fundamental Particle Physics

Background:

• Positronium (Ps) is a simple leptonic atom, crucial for testing fundamental theories.
• Precise measurements of energy levels in Ps provide stringent tests of QED.
• The 2³S₁→2³P₂ transition (ν₂) is a key observable for theoretical validation.

Purpose of the Study:

• To accurately measure the 2³S₁→2³P₂ transition frequency (ν₂) in positronium.
• To employ a phase-variation separated oscillatory fields technique for high-precision measurement.
• To compare experimental results with theoretical predictions from QED.

Main Methods:

• A beam of positronium atoms in the 2³S₁ state was utilized.
• Two spatially separated, coherent microwave fields were applied, tuned near the ν₂ resonance.
• The surviving beam fraction was measured as a function of the relative phase between the fields.
• The resonance frequency was determined from the phase's frequency dependence, avoiding full spectral scans.

Main Results:

• The 2³S₁→2³P₂ interval (ν₂) was measured to be 8626.39±1.17_stat±0.80_sys MHz.
• The experimental result shows agreement with theoretical predictions from quantum electrodynamics.
• The phase-variation technique allowed for precise frequency determination without extensive spectral line scanning.

Conclusions:

• The measured ν₂ frequency in positronium is consistent with QED calculations.
• This experiment demonstrates the efficacy of the phase-variation separated oscillatory fields technique for high-precision atomic spectroscopy.
• The findings contribute to the ongoing validation of fundamental physical theories through precision measurements.