Precision Microwave Spectroscopy of the Positronium 2 ^{3}S_{1}→2 ^{3}P_{2} Interval.

Area of Science:

• Atomic Physics
• Quantum Electrodynamics
• Spectroscopy

Background:

• Positronium (Ps) is a fundamental leptonic atom, crucial for testing quantum electrodynamics (QED).
• Precise measurement of energy intervals in positronium provides stringent tests of QED predictions.
• Previous measurements of the 2³S₁→2³P₂ interval were limited by microwave reflection effects.

Purpose of the Study:

• To perform a new, high-precision measurement of the positronium 2³S₁→2³P₂ (ν₂) transition frequency.
• To mitigate systematic errors, particularly those arising from microwave reflections, that affected prior experiments.
• To compare the experimental result with theoretical QED calculations.

Main Methods:

• Utilized a modified experimental setup to minimize microwave reflections.
• Employed high-resolution spectroscopy to measure the ν₂ transition frequency.
• Analyzed spectral line shapes and shifts to account for residual experimental imperfections.

Main Results:

• The experimental value for the ν₂ interval was determined to be 8627.94±0.95 MHz.
• This experimental result is within 1.3 standard deviations (σ) of the theoretical value.
• The improved apparatus significantly reduced line shape distortions and shifts caused by microwave reflections.

Conclusions:

• The new measurement of the positronium 2³S₁→2³P₂ interval provides a precise experimental value.
• The agreement between experiment and theory supports the accuracy of current QED calculations for positronium.
• The refined experimental technique offers a pathway for even more precise future measurements in atomic systems.