223 research outputs found
Precise measurement of HFS of positronium
The ground state hyperfine splitting in positronium, , is sensitive to high order corrections of QED. A new
calculation up to has revealed a discrepancy
between the QED prediction and the experimental results. This discrepancy might
either be due to systematic problems in the previous experiments or to
contributions beyond the Standard Model. We propose an experiment to measure
employing new methods designed to remedy the systematic
errors which may have affected the previous experiments. Our experiment will
provide an independent check of the discrepancy. The measurement is in progress
and a preliminary result of has been obtained. A measurement with a
precision of O(1) ppm is expected within a few years.Comment: 5 pages, 6 figures, contributed to POSMOL 2009, will be published in
J. Phys.: Conf. Serie
Measurement of Positronium hyperfine splitting with quantum oscillation
Interference between different energy eigenstates in a quantum system results
in an oscillation with a frequency which is proportional to the difference in
energy between the states. Such an oscillation is observable in polarized
positronium when it is placed in a magnetic field. In order to measure the
hyperfine splitting of positronium, we perform the precise measurement of this
oscillation using a high quality superconducting magnet and fast
photon-detectors. A result of ~GHz is obtained which is consistent with both theoretical
calculations and previous precise measurements.Comment: 4 figures accepted by Phys. Lett.
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