Double-trap measurement of the proton magnetic moment at 0.3 parts per billion precision

Schneider, G.; Mooser, A.; Bohman, Matthew; Schön, Natalie; Harrington, James A.; Higuchi, Takashi; Nagahama, H.; Sellner, Stefan; Smorra, Christian; Blaum, Klaus; Matsuda, Y.; Quint, W.; Walz, J.; Ulmer, S.

doi:10.1126/science.aan0207

Cited by 112 publications

(127 citation statements)

References 35 publications

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“…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.…”

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confidence: 90%

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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confidence: 90%

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

et al. 2019

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“…Here we combine the published results from the two recent BASE experiments [1,2] to obtain constraints on the SME coefficients in the Sun-centered frame. A comparison between the two measured g factors for protons and antiprotons gives…”

Section: Base Experiments At Mainz and Cernmentioning

confidence: 99%

Lorentz and CPT Tests Using Penning Traps

Ding

2019

Symmetry

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The theoretical prospects for quantum electrodynamics with Lorentz-violating operators of mass dimensions up to six are revisited in this work. The dominant effects due to Lorentz and CPT violation are studied in measurements of magnetic moments of particles confined in Penning traps. Using recently reported experimental results, new coefficients for Lorentz violation are constrained and existing bounds of various coefficients are improved.

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“…The experimental technique is discussed along with the expected sensitivities. PACS numbers: 13.35.Dx, 13.40.Em, 14.60.Fg Measurements of the electromagnetic dipole moments for common particles like the electron, muon and nucleons, combined with precise theoretical calculations, provide stringent tests of physics within and beyond the Standard Model (SM) [1][2][3][4][5][6][7][8]. For short-lived particles like heavy baryons and the τ lepton, the short lifetime (∼ 10 −13 s) prevents the use of the spin-precession technique adopted in the muon g − 2 experiment [3,4].…”

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confidence: 99%

Novel Method for the Direct Measurement of theτLepton Dipole Moments

Giorgi

Henry

et al. 2019

Phys. Rev. Lett.

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A novel method for the direct measurement of the elusive magnetic and electric dipole moments of the τ lepton is presented. The experimental approach relies on the production of τ + leptons from D + s → τ + ντ decays, originating in fixed-target collisions at the LHC. A sample of polarized τ + leptons is kinematically selected and subsequently channeled in a bent crystal. The magnetic and electric dipole moments of the τ + lepton are measured by determining the rotation of the spinpolarization vector induced by the intense electromagnetic field between crystal atomic planes. The experimental technique is discussed along with the expected sensitivities. PACS numbers: 13.35.Dx, 13.40.Em, 14.60.Fg Measurements of the electromagnetic dipole moments for common particles like the electron, muon and nucleons, combined with precise theoretical calculations, provide stringent tests of physics within and beyond the Standard Model (SM) [1][2][3][4][5][6][7][8]. For short-lived particles like heavy baryons and the τ lepton, the short lifetime (∼ 10 −13 s) prevents the use of the spin-precession technique adopted in the muon g − 2 experiment [3,4]. Recently, the possibility of directly measuring the electromagnetic dipole moments of short-lived baryons, produced in fixed-target collisions at the Large Hadron Collider (LHC) and channeled in bent crystals [9][10][11][12][13][14], has been considered. For the τ lepton, the use of B + → τ + ν τ decays was suggested [15] and more recently the D + s → τ + ν τ process with higher yield has been explored [16]. In this Letter, a novel method that fully exploits the polarization properties of τ + leptons produced in D + s decays is proposed. The magnetic (MDM) and the electric (EDM) dipole moments are defined as µ = ge /(2m τ c)s/2 and δ = de /(2m τ c)s/2, respectively, where m τ is the τ mass, g (d) is the gyromagnetic (gyroelectric) factor, and s is the spin-polarization vector [17]. In the SM, the τ anomalous MDM is expected to be a = (g − 2)/2 ≈ 10 −3 [18], and its EDM, d, to be minuscule [19]. However, the dipole moments can be largely enhanced in the presence of physics beyond the SM [20,21]. Methods based on precise measurements of the τ + τ − pair production cross section in e + e − annihilations set indirect limits on a at the few percent level [22], still above the SM prediction, and lead to limits on δ at 10 −16 e cm level [23]. Other indirect measurements have been suggested to improve the precision [20,24,25].The proposed solution to provide direct measurements of the τ dipole moments, illustrated in Fig. 1, is based on the large production cross section of high-energy polarized τ + leptons, originating in proton fixed-target col-Z y D + s τ + W target θ y,D s τ p Y z θ y π + π + π − c r y s t a l sν τ ν τ FIG. 1: (color online). Sketch of the fixed-target setup along with the τ + production and decay processes (not to scale). The crystal frame (X,Y ,Z) is tilted in the laboratory frame (x, y, z) by θy to avoid channeling of non-interacting protons.lisions at the LHC. T...

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Double-trap measurement of the proton magnetic moment at 0.3 parts per billion precision

Cited by 112 publications

References 35 publications

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

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

Lorentz and CPT Tests Using Penning Traps

Novel Method for the Direct Measurement of theτLepton Dipole Moments

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