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Pérez, P.; Banerjee, D.; Biraben, F.; Brook-Roberge, D.; Charlton, M.; Cladé, P.; Comini, P.; Crivelli, P.; Dalkarov, O.; Debu, P.; Douillet, A.; Dufour, G.; Dupré, P.; Eriksson, S.; Froelich, P.; Grandemange, P.; Guellati, S.; Guérout, R.; Heinrich, J. M.; Hervieux, P.-A.; Hilico, L.; Husson, A.; Indelicato, P.; Jonsell, Svante; Karr, J.-P.; Khabarova, K.; Kolachevsky, N.; Kuroda, N.; Lambrecht, A.; Leite, A. M. M.; Liszkay, L.; Lunney, D.; Madsen, N.; Manfredi, G.; Mansoulié, B.; Matsuda, Y.; Mohri, A.; Mortensen, T.; Nagashima, Y.; Nesvizhevsky, V.; Nez, F.; Regenfus, C.; Rey, J.-M.; Reymond, J.-M.; Reynaud, S.; Rubbia, A.; Sacquin, Y.; Schmidt-Kaler, F.; Sillitoe, N.; Staszczak, M.; Szabo-Foster, C. I.; Torii, H.; Vallage, B.; Valdes, M.; Werf, D. P. van der; Voronin, A.; Walz, J.; Wolf, S.; Wronka, S.; Yamazaki, Y.

doi:10.1007/978-3-319-45018-6_3

Cited by 12 publications

(13 citation statements)

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“…In recent years numerous experiments have successfully trapped, or formed a beam of, antihydrogen atoms. These experiments aim to test CPT symmetry by comparing the properties of the antihydrogen atom to those of the hydrogen atom [1][2][3][4], or test the effects of gravity on antimatter [5][6][7]. Antihydrogen is produced either by injecting antiproton and positron plasmas into cryogenic electro-magnetic traps where three-body recombination takes place ( -¯) .…”

Section: Introductionmentioning

confidence: 99%

Efficient antihydrogen detection in antimatter physics by deep learning

et al. 2017

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Antihydrogen is at the forefront of antimatter research at the CERN Antiproton Decelerator. Experiments aiming to test the fundamental CPT symmetry and antigravity effects require the efficient detection of antihydrogen annihilation events, which is performed using highly granular tracking detectors installed around an antimatter trap. Improving the efficiency of the antihydrogen annihilation detection plays a central role in the final sensitivity of the experiments. We propose deep learning as a novel technique to analyze antihydrogen annihilation data, and compare its performance with a traditional track and vertex reconstruction method. We report that the deep learning approach yields significant improvement, tripling event coverage while simultaneously improving performance in terms of AUC by 5%.

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Section: Introductionmentioning

confidence: 99%

Efficient antihydrogen detection in antimatter physics by deep learning

et al. 2017

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“…Possible production of Bose-Einstein condensate of Ps has also been predicted [7,8], besides the importance of Ps in diagnosing porous materials [9] as well as in probing bound-state QED effects [10]. Moreover, efficient Ps formation is the precursor of the production of dipositronium molecules [11] and antihydrogen atoms [12,13] required to study the effect of gravitational force on antimatter [14,15].Theoretical investigations to calculate Ps formation cross sections from atomic hydrogen [16][17][18], noble gases [19][20][21], and alkali metals [22,23] are aplenty. Calculations with molecular targets, although relatively limited, include the molecular hydrogen [24], polyatomic molecules [25], and the water molecule [26].…”

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confidence: 99%

Ubiquitous diffraction resonances in positronium formation from fullerenes

Hervieux

Chakraborty

2017

Phys. Rev. A

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Due to the dominant electron capture by positrons from the molecular wall and the spatial dephasing across the wall-width, a powerful diffraction effect universally underlies the positronium (Ps) formation from fullerenes. This results into trains of resonances in the Ps formation cross section as a function of the positron beam energy, producing uniform structures in recoil momenta in analogy with classical single-slit diffraction fringes in the configuration space. The prediction opens a hitherto unknown avenue of Ps spectroscopy with nanomaterials.PACS numbers: 34.80. Lx, 36.10.Dr, Following the impact of positrons with matter the formation of exotic electron-positron bound-pair, the positronium (Ps), is a vital process in nature. This channel accounts for as large as half of the positron scattering cross section from simple atoms and molecules [1], as well as an even higher success rate of Ps formation on surfaces and thin films [2]. Other than probing structure and reaction mechanism of matters, the Ps formation is a unique pathway to the electron-positron annihilation process [3,4] with both astrophysical [5] and applied [6] interests. Possible production of Bose-Einstein condensate of Ps has also been predicted [7,8], besides the importance of Ps in diagnosing porous materials [9] as well as in probing bound-state QED effects [10]. Moreover, efficient Ps formation is the precursor of the production of dipositronium molecules [11] and antihydrogen atoms [12,13] required to study the effect of gravitational force on antimatter [14,15].Theoretical investigations to calculate Ps formation cross sections from atomic hydrogen [16][17][18], noble gases [19][20][21], and alkali metals [22,23] However, in spite of such broad landscape of Ps research, little attempt of Ps formation by implanting positrons in nanoparticles, in gas or solid phase, has so far been made, except for a single theoretical study using Na clusters [36]. On the other hand, straddling the line between atoms and condensed matters are clusters and nanostructures that not only have hybrid properties of the two extremes, but also exhibit outstanding behaviors with unusual spectroscopic effects [37]. Formation of a quasi-free electron gas within a finite nanoscopic region of well-defined boundary, as opposed to a longer-range, highly diffused Coulomb-type boundary characteristic of atoms and molecules, is a property of nanosystems which ensures predominant electron capture from localized regions in space. This may lead to diffraction in the capture amplitude, particularly at positron energies that cannot excite plasmon modes. The Ps formation from fullerenes can be singularly attractive to access this diffraction phenomenon due to fullerene's eminent symmetry and stability, and its previous track record of success in spectroscopic experiments [38]. In this communication, we show that the Ps formation amplitude from the positron colliding with C 60 does include a strong diffraction effect, resulting in a system of peaks in the form of broad shape ...

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“…It has recently been demonstrated that4 10 9 positrons can be stored in an accumulator [39]. Whilst this is, in principle, sufficient to ensure that = f 100% n using our simple approximation, we note that: (i) further gains in positron number are feasible using laboratorybased positron systems with extra storage capabilities [40], (ii) sources with significantly higher positron fluxes are under development [41] and (iii) higher fluxes are available at existing facility based sources [42]. Figure 1.…”

Section: Estimate Of Required Positronium Fluxmentioning

confidence: 83%

Cold neutral atoms via charge exchange from excited state positronium: a proposal

2017

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We present a method for generating cold neutral atoms via charge exchange reactions between trapped ions and Rydberg positronium. The high charge exchange reaction cross section leads to efficient neutralisation of the ions and since the positronium-ion mass ratio is small, the neutrals do not gain appreciable kinetic energy in the process. When the original ions are cold the reaction produces neutrals that can be trapped or further manipulated with electromagnetic fields. Because a wide range of species can be targeted we envisage that our scheme may enable experiments at low temperature that have been hitherto intractable due to a lack of cooling methods. We present an estimate for achievable temperatures, neutral number and density in an experiment where the neutrals are formed at a milli-Kelvin temperature from either directly or sympathetically cooled ions confined on an ion chip. The neutrals may then be confined by their magnetic moment in a co-located magnetic minimum well also formed on the chip. We discuss general experimental requirements.

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Cited by 12 publications

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Efficient antihydrogen detection in antimatter physics by deep learning

Efficient antihydrogen detection in antimatter physics by deep learning

Ubiquitous diffraction resonances in positronium formation from fullerenes

Cold neutral atoms via charge exchange from excited state positronium: a proposal

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