Observation of positronium annihilation in the 2S state: towards a new measurement of the 1S-2S transition frequency

Cooke, D.; Alnis, Jānis; Antognini, Aldo; Brown, B. L.; Friedreich, S.; Gabard, A.; Haensch, Theodor W.; Kirch, K.; Rubbia, A.; Vranković, V.

doi:10.1007/s10751-015-1158-4

Cited by 35 publications

(31 citation statements)

References 23 publications

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“…Possibly transitions that do not involve the ground state can be used, but only if the atoms are not spreading out to much, which would essentially mean they were already cold. Alternatively, it may be possible to contain Ps atoms in some sort of physical structure that does not inhibit laser interactions [123] and achieve some cooling. Although I am skeptical of the utility of such a scheme, if it does turn out to be possible it could allow fine control of the Ps temperature in a BEC experiment and provide a way to scan through T C .…”

Section: Discussionmentioning

confidence: 99%

“…There are currently some new experiments in progress that aim to improve the 1 3 S 1 -2 3 S 1 uncertainty [76,123,504]. At the time of the previous experiments the theoretical uncertainly (2.6 MHz [505]) was comparable to the experimental value (3.2 MHz, 2.6 ppb [107]).…”

Section: Doppler-free Two-photon Transitionsmentioning

confidence: 95%

“…Since they can be difficult to stabilize and are often incompatible with other experimental requirements this methodology is not widely used in Ps research; the only other example in addition to the precision experiments of Fee et al [107] is that of reference [123]. High instantaneous laser intensities can be produced relatively easily using pulsed lasers.…”

Section: Optical Excitation Of Positronium Atomsmentioning

confidence: 99%

“…This means that atoms cannot be selected according to their velocity, and laser cooling will be ineffective. Thus, while laser cooling for a confined Ps gas can be envisioned [676], the effects of confinement would have to be explicitly addressed, either by using sufficiently large cavities or other confining structures [123], or possibly by using alternative cooling schemes employing short-pulsed lasers (e.g. [677,678]).…”

Section: Bose-einstein Condensationmentioning

confidence: 99%

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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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Section: Discussionmentioning

confidence: 99%

Section: Doppler-free Two-photon Transitionsmentioning

confidence: 95%

Section: Optical Excitation Of Positronium Atomsmentioning

confidence: 99%

Section: Bose-einstein Condensationmentioning

confidence: 99%

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Experimental progress in positronium laser physics

2018

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“…3 S transition frequency are expected from a combination of Ps detection techniques, also using the observation of the 2 3 S state annihilation [9]. Other QED tests are based upon the determination of the Ps n = 2 fine structure splitting, in particular using microwaves to induce electric-dipole transitions between the metastable 2 3 S state (produced by impinging positron beams on metal surfaces [10]) and the 2 3 P sublevels [11].…”

Section: S-2mentioning

confidence: 99%

Producing long-lived 23S positronium via 33P laser excitation in magnetic and electric

Aghion¹,

Amsler²,

Antonello³

et al. 2018

Phys. Rev. A

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Producing positronium (Ps) in the metastable 2 3 S state is of interest for various applications in fundamental physics. We report here on an experiment in which Ps atoms are produced in this long-lived state by spontaneous radiative decay of Ps excited to the 3 3 P level manifold. The Ps cloud excitation is obtained with a UV laser pulse in an experimental vacuum chamber in presence of guiding magnetic field of 25 mT and an average electric field of 300 V cm −1 . The evidence of the 2 3 S state production is obtained to the 3.6σ level of statistical significance using a novel analysis technique of the single-shot positronium annihilation lifetime spectra. The dynamic of the Ps population on the involved levels has been studied with a rate equation model.

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The Mu-MASS (muonium laser spectroscopy) experiment

Crivelli

2018

Hyperfine Interact

Self Cite

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We present a new experiment, Mu-MASS, aiming for a 1000-fold improvement in the determination of the 1S-2S transition frequency of Muonium (M), the positive-muon/electron bound state. This substantial improvement beyond the current state-of-the-art relies on the novel cryogenic M converters and confinement techniques we developed, on the new excitation and detection schemes which we implemented for positronium spectroscopy and the tremendous advances in generation of UV radiation. This experiment is planned to be performed at the Paul Scherrer Institute (PSI). Interesting anomalies in the muon sector have accumulated: notably the famous anomalous muon magnetic moment (g-2) and the muonic hydrogen Lamb shift measurement which prompted the so-called proton charge radius puzzle. These tantalizing results triggered vibrant activity on both experimental and theoretical sides. Different explanations have been put forward including exciting solutions invoking New Physics beyond the Standard Model. Mu-MASS could contribute to clarifying the origin of these anomalies by providing robust and reliable values of fundamental constants such as the muon mass and a value of the Rydberg constant independent of finite size effects.

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Observation of positronium annihilation in the 2S state: towards a new measurement of the 1S-2S transition frequency

Cited by 35 publications

References 23 publications

Experimental progress in positronium laser physics

Experimental progress in positronium laser physics

Producing long-lived 23S positronium via 33P laser excitation in magnetic and electric

The Mu-MASS (muonium laser spectroscopy) experiment

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