Improved limit on the directly measured antiproton lifetime

Sellner, Stefan; Besirli, Mustafa; Bohman, Matthew; Borchert, M. J.; Harrington, James A.; Higuchi, Takashi; Mooser, A.; Nagahama, H.; Schneider, G.; Smorra, Christian; Tanaka, T.; Blaum, Klaus; Matsuda, Y.; Ospelkaus, C.; Quint, W.; Walz, J.; Yamazaki, Y.; Ulmer, S.

doi:10.1088/1367-2630/aa7e73

Cited by 42 publications

(42 citation statements)

References 22 publications

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“…The application of voltage ramps to electrodes that interconnect the traps allows adiabatic shuttling of the particles between the traps. The electrode assembly is placed inside an indium-sealed trap can in which the low pressure enables antiprotons to be stored for years 19,29 . Each of the traps is equipped with a sensitive tuned circuit for non-destructive image current detection of the particles' axial oscillation frequencies at ν z ≈ 675 kHz (ref.…”

mentioning

confidence: 99%

A parts-per-billion measurement of the antiproton magnetic moment

Smorra

Sellner²,

Borchert

et al. 2017

Nature

130

145

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Precise comparisons of the fundamental properties of matterantimatter conjugates provide sensitive tests of charge-parity-time (CPT) invariance 1 , which is an important symmetry that rests on basic assumptions of the standard model of particle physics. Experiments on mesons 2 , leptons 3,4 and baryons 5,6 have compared different properties of matter-antimatter conjugates with fractional uncertainties at the parts-per-billion level or better. One specific quantity, however, has so far only been known to a fractional uncertainty at the parts-per-million level 7,8 : the magnetic moment of the antiproton, μ p . The extraordinary difficulty in measuring μ p with high precision is caused by its intrinsic smallness; for example, it is 660 times smaller than the magnetic moment of the positron 3 . Here we report a high-precision measurement of μ p in units of the nuclear magneton μ N with a fractional precision of 1.5 parts per billion (68% confidence level). We use a two-particle spectroscopy method in an advanced cryogenic multi-Penning trap system. Our result μ p = −2.7928473441(42)μ N (where the number in parentheses represents the 68% confidence interval on the last digits of the value) improves the precision of the previous best μ p measurement 8 by a factor of approximately 350. The measured value is consistent with the proton magnetic moment 9 , μ p = 2.792847350(9)μ N , and is in agreement with CPT invariance. Consequently, this measurement constrains the magnitude of certain CPT-violating effects 10 to below 1.8 × 10 −24 gigaelectronvolts, and a possible splitting of the protonantiproton magnetic moments by CPT-odd dimension-five interactions to below 6 × 10 −12 Bohr magnetons 11 .Within the physics programme at the Antiproton Decelerator of CERN, the properties of protons and antiprotons 5,6 , antiprotons and electrons 12 , and hydrogen 13 and antihydrogen 14,15 are compared with high precision. Such experiments, including those described here, provide stringent tests of CPT invariance. Our presented antiproton magnetic moment measurement reaches a fractional precision of 1.5 parts per billion (p.p.b.) at 68% confidence level, enabled by our new measurement scheme. Compared to the double-Penning trap technique 16 used in the measurement of the proton magnetic moment 9 , this new method eliminates the need for cyclotron cooling in each measurement cycle and increases the sampling rate.Our technique uses a hot cyclotron antiproton for measurements of the cyclotron frequency ν c , and a cold Larmor antiproton to determine the Larmor frequency ν L . By evaluating the ratio of the frequencies measured in the same magnetic field, the magnetic moment of the antiproton (in units of the nuclear magneton, the g-factor) ν ν μ μN is obtained. With this new technique we have improved the precision of the previous best antiproton magnetic moment measurement 8 by a factor of approximately 350 (Fig. 1a).Our experiment 17 is located in the Antiproton Decelerator facility, which provides bunches of 30 million antiprotons at a...

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confidence: 99%

A parts-per-billion measurement of the antiproton magnetic moment

Smorra

Sellner²,

Borchert

et al. 2017

Nature

130

145

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“…For the BASE analysis trap, ν + ≈ 17.845 MHz, ν − ≈ 10 kHz and ν z ≈ 675 kHz. The gold-plated OFHC electrodes are placed inside an indium-sealed vacuum chamber which is cooled to T ≈ 6 K. Cryo-pumping provides an ultra-high vacuum with pressures < 3 × 10 −18 mbar which enables storage times > 10 a [23]. Radio frequency (rf) lines equipped with high order low-pass and band-pass filters as well as high-insulation switches are used for particle manipulation ( Fig.…”

mentioning

confidence: 99%

“…A trapped ion polarizes neutral background gas atoms and thereby induces collisions described by the Langevin rate γ, which is proportional to the background gas density [35,42]. From our antiproton lifetime measurement [23] we derived upper limits for the partial pressure of hydrogen p upper,H < 1.2 × 10 −18 mbar and helium p upper,He < 2.7 × 10 −18 mbar leading to ζ + < 4 × 10 −9 s −1 . Voltage supply (UM1-14) noise at ν + is ruled out by independent measurements.…”

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confidence: 99%

Measurement of Ultralow Heating Rates of a Single Antiproton in a Cryogenic Penning Trap

et al. 2019

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We report on the first detailed study of motional heating in a cryogenic Penning trap using a single antiproton. Employing the continuous Stern-Gerlach effect we observe cyclotron quantum transition rates of 6(1) quanta/h and an electric field noise spectral density below 7.5(3.4)×10 −20 V 2 m −2 Hz −1 , which corresponds to a scaled noise spectral density below 8.8(4.0) × 10 −12 V 2 m −2 , results which are more than two orders of magnitude smaller than those reported by other ion trap experiments.Quantum control techniques applied to trapped charged particles, well-isolated from environmental influences, have very versatile applications in metrology and quantum information processing. For example, elegant experiments on co-trapped laser cooled ions in Paul traps have provided highly precise state-of-the-art quantum logic clocks [1], enabled the development of exquisite atomic precision sensors [2] and the implementation of quantum information algorithms applied with highly entangled ion-crystals [3]. Decoherence effects from noise driven quantum transitions, commonly referred to as anomalous heating [4,5], affect the scalability of multiion systems, which would enable even more powerful algorithms. Trapped particles are also highly sensitive probes to test fundamental symmetries, and to search for physics beyond the standard model [6,7]. The most precise values of the mass of the electron [8] and the most stringent tests of bound-state quantum electrodynamics [9] are based on precise frequency measurements on highly-charged ions in Penning traps. Measurements of the properties of trapped electrons [10] and positrons [11] provide the most sensitive tests of quantum electrodynamics and of the fundamental charge-parity-time (CPT) invariance in the lepton sector [12,13]. Our experiments [14] make high-precision comparisons of the fundamental properties of protons and antiprotons, and provide stringent tests of CPT invariance in the baryon sector. We recently reported on an improved determination of the proton magnetic moment with a fractional precision of 300 parts in a trillion [16] and the * matthias.joachim.borchert@cern.ch first high-precision determination of the antiproton magnetic moment with a fractional precision of 1.5 parts in a billion [15]. This measurement, based on a newly invented multi-trap method, improves the fractional precision achieved in previous studies [17,18] by more than a factor of 3000. These multi-trap based high-precision magnetic moment measurements on protons and antiprotons require low-noise conditions much more demanding than in any other ion trap experiment. Compared to experiments on electrons and positrons [10,11], the 660fold smaller proton/antiproton magnetic moment makes it much more challenging to apply high-fidelity single particle spin-quantum spectroscopy techniques [19]. Our experiments become possible only in cryogenic ultra-lownoise Penning-trap instruments, which provide energy stabilities of the particle motion on the peV/s range, effectively corresponding to a para...

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“…Hence, while in order to increase statistical precision it is necessary to repeat measurements of f c ' and f z , measurements of f m are only needed to obtain and check the stability of δ. In Penning traps used for the most precise measurements, the chamber housing the electrodes is maintained at close to LHe temperature, resulting in extreme (<<10 −15 mbar) high-vacuum [19]. Hence single ions can be trapped and manipulated, and measurements made on them for many days.…”

Section: The Precision Penning Trapmentioning

confidence: 99%

High-Precision Atomic Mass Measurements for Fundamental Constants

Myers

2019

Atoms

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Atomic mass measurements are essential for obtaining several of the fundamental constants. The most precise atomic mass measurements, at the 10−10 level of precision or better, employ measurements of cyclotron frequencies of single ions in Penning traps. We discuss the relation of atomic masses to fundamental constants in the context of the revised SI. We then review experimental methods, and the current status of measurements of the masses of the electron, proton, neutron, deuteron, tritium, helium-3, helium-4, oxygen-16, silicon-28, rubidium-87, and cesium-133. We conclude with directions for future work.

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Improved limit on the directly measured antiproton lifetime

Cited by 42 publications

References 22 publications

A parts-per-billion measurement of the antiproton magnetic moment

A parts-per-billion measurement of the antiproton magnetic moment

Measurement of Ultralow Heating Rates of a Single Antiproton in a Cryogenic Penning Trap

High-Precision Atomic Mass Measurements for Fundamental Constants

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