The Direct Spectroscopy of Positronium Hyperfine Structure Using a Sub-THz Gyrotron

Miyazaki, Akira; Yamazaki, T.; Suehara, Taikan; Namba, T.; Asai, S.; Kobayashi, T.; Saito, Haruo; Idehara, T.; Ogawa, I.; Tatematsu, Y.

doi:10.1007/s10762-013-0001-8

Cited by 27 publications

(9 citation statements)

References 16 publications

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“…The stored power is always over 20 kW, which is twice as high as previous power (11 kW). The result is consistent with a rough estimated P eff considering the finesse (400-600) and coupling (about 60%) of the cavity [8]. To control P eff for all frequency points, we placed a wire grid polarizer between the gyrotron and the Fabry-Pérot cavity.…”

Section: Power Estimationsupporting

confidence: 81%

First millimeter-wave spectroscopy of ground-state positronium

Miyazaki

Yamazaki

Suehara

et al. 2015

Progress of Theoretical and Experimental Physics

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We report on the first measurement of the Breit-Wigner resonance of the transition from ortho-positronium to para-positronium. We have developed an optical system to accumulate a power of over 20 kW using a frequency-tunable gyrotron and a Fabry-Pérot cavity. This system opens a new era of millimeter-wave spectroscopy, and enables us to directly determine both the hyperfine interval and the decay width of p-Ps.

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Section: Power Estimationsupporting

confidence: 81%

First millimeter-wave spectroscopy of ground-state positronium

Miyazaki

Yamazaki

Suehara

et al. 2015

Progress of Theoretical and Experimental Physics

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“…A recent experiment [323] has in fact succeeded in driving a direct singlet-triplet transition using a highpower (300 W) gyrotron and a Fabry-Pérot cavity (with gold mesh mirrors) to produce up to 10 kW of 203 GHz microwave radiation [324,325]. The basic methodology used in this experiment is similar to the earlier Zeemansplit measurements, except of course for the formidable challenges related to producing intense radiation at the required frequencies [326].…”

Section: Ps In Electric and Magnetic Fieldsmentioning

confidence: 98%

Experimental progress in positronium laser physics

2018

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Abstract. The field of experimental positronium physics has advanced significantly in the last few decades, with new areas of research driven by the development of techniques for trapping and manipulating positrons using Surko-type buffer gas traps. Large numbers of positrons (typically ≥10 6 ) accumulated in such a device may be ejected all at once, so as to generate an intense pulse. Standard bunching techniques can produce pulses with ns (mm) temporal (spatial) beam profiles. These pulses can be converted into a dilute Ps gas in vacuum with densities on the order of 10 7 cm −3 which can be probed by standard ns pulsed laser systems. This allows for the efficient production of excited Ps states, including long-lived Rydberg states, which in turn facilitates numerous experimental programs, such as precision optical and microwave spectroscopy of Ps, the application of Stark deceleration methods to guide, decelerate and focus Rydberg Ps beams, and studies of the interactions of such beams with other atomic and molecular species. These methods are also applicable to antihydrogen production and spectroscopic studies of energy levels and resonances in positronium ions and molecules. A summary of recent progress in this area will be given, with the objective of providing an overview of the field as it currently exists, and a brief discussion of some future directions.

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“…One experiment is trying to measure ∆ HFS directly, but it has not obtained the result yet [12,13]. Other independent experiments [14,15] have not yet reached a sufficient level of precision to address the discrepancy.…”

Section: Introductionmentioning

confidence: 99%

New Precision Measurement of Hyperfine Splitting of Positronium

Ishida

2017

DDF

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The ground state hyperfine splitting of positronium ∆ HFS is sensitive to high order corrections of quantum electrodynamics (QED) in bound state. The theoretical prediction and the averaged experimental value for ∆ HFS has a discrepancy of 15 ppm, which is equivalent to 3.9 standard deviations (s.d.). A new precision measurement which reduces the systematic uncertainty from the positronium thermalization effect was performed, in which the non-thermalization effect was measured to be as large as 10 ± 2 ppm in a timing window we used. When this effect is taken into account, our new result becomes ∆ HFS = 203.394 2 ± 0.001 6(stat., 8.0 ppm) ± 0.001 3(sys., 6.4 ppm) GHz, which favors the QED prediction within 1.2 s.d. and disfavors the previous experimental average by 2.6 s.d.

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The Direct Spectroscopy of Positronium Hyperfine Structure Using a Sub-THz Gyrotron

Cited by 27 publications

References 16 publications

First millimeter-wave spectroscopy of ground-state positronium

First millimeter-wave spectroscopy of ground-state positronium

Experimental progress in positronium laser physics

New Precision Measurement of Hyperfine Splitting of Positronium

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