172 results on '"Jonsell, S"'
Search Results
2. Production of antihydrogen atoms by 6 keV antiprotons through a positronium cloud
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Adrich, P., Blumer, P., Caratsch, G., Chung, M., Cladé, P., Comini, P., Crivelli, P., Dalkarov, O., Debu, P., Douillet, A., Drapier, D., Froelich, P., Garroum, N., Guellati-Khelifa, S., Guyomard, J., Hervieux, P-A., Hilico, L., Indelicato, P., Jonsell, S., Karr, J-P., Kim, B., Kim, S., Kim, E-S., Ko, Y. J., Kosinski, T., Kuroda, N., Latacz, B. M., Lee, B., Lee, H., Lee, J., Lim, E., Liszkay, L., Lunney, D., Manfredi, G., Mansoulié, B., Matusiak, M., Nesvizhevsky, V., Nez, F., Niang, S., Ohayon, B., Park, K., Paul, N., Pérez, P., Regenfus, C., Reynaud, S., Roumegou, C., Roussé, J-Y., Sacquin, Y., Sadowski, G., Sarkisyan, J., Sato, M., Schmidt-Kaler, F., Staszczak, M., Szymczyk, K., Tanaka, T. A., Tuchming, B., Vallage, B., Voronin, A., van der Werf, D. P., Won, D., Wronka, S., Yamazaki, Y., Yoo, K-H., and Yzombard, P.
- Subjects
High Energy Physics - Experiment ,Physics - Instrumentation and Detectors - Abstract
We report on the first production of an antihydrogen beam by charge exchange of 6.1 keV antiprotons with a cloud of positronium in the GBAR experiment at CERN. The antiproton beam was delivered by the AD/ELENA facility. The positronium target was produced from a positron beam itself obtained from an electron linear accelerator. We observe an excess over background indicating antihydrogen production with a significance of 3-4 standard deviations.
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- 2023
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3. Observation of the effect of gravity on the motion of antimatter.
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Anderson, E, Baker, C, Bertsche, W, Bhatt, N, Bonomi, G, Capra, A, Carli, I, Cesar, C, Charlton, M, Christensen, A, Collister, R, Cridland Mathad, A, Duque Quiceno, D, Eriksson, S, Evans, A, Evetts, N, Fabbri, S, Ferwerda, A, Friesen, T, Fujiwara, M, Gill, D, Golino, L, Gomes Gonçalves, M, Grandemange, P, Granum, P, Hangst, J, Hayden, M, Hodgkinson, D, Hunter, E, Isaac, C, Jimenez, A, Johnson, M, Jones, J, Jones, S, Jonsell, S, Khramov, A, Madsen, N, Martin, L, Massacret, N, Maxwell, D, McKenna, J, Menary, S, Momose, T, Mostamand, M, Mullan, P, Nauta, J, Olchanski, K, Oliveira, A, Peszka, J, Powell, A, Rasmussen, C, Robicheaux, F, Sacramento, R, Sameed, M, Sarid, E, Schoonwater, J, Silveira, D, Singh, J, Smith, G, So, C, Stracka, S, Stutter, G, Tharp, T, Thompson, K, Thompson, R, Thorpe-Woods, E, Torkzaban, C, Urioni, M, Woosaree, P, Wurtele, Jonathan, and Fajans, Joel
- Abstract
Einsteins general theory of relativity from 19151 remains the most successful description of gravitation. From the 1919 solar eclipse2 to the observation of gravitational waves3, the theory has passed many crucial experimental tests. However, the evolving concepts of dark matter and dark energy illustrate that there is much to be learned about the gravitating content of the universe. Singularities in the general theory of relativity and the lack of a quantum theory of gravity suggest that our picture is incomplete. It is thus prudent to explore gravity in exotic physical systems. Antimatter was unknown to Einstein in 1915. Diracs theory4 appeared in 1928; the positron was observed5 in 1932. There has since been much speculation about gravity and antimatter. The theoretical consensus is that any laboratory mass must be attracted6 by the Earth, although some authors have considered the cosmological consequences if antimatter should be repelled by matter7-10. In the general theory of relativity, the weak equivalence principle (WEP) requires that all masses react identically to gravity, independent of their internal structure. Here we show that antihydrogen atoms, released from magnetic confinement in the ALPHA-g apparatus, behave in a way consistent with gravitational attraction to the Earth. Repulsive antigravity is ruled out in this case. This experiment paves the way for precision studies of the magnitude of the gravitational acceleration between anti-atoms and the Earth to test the WEP.
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- 2023
4. Positron accumulation in the GBAR experiment
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Blumer, P., Charlton, M., Chung, M., Clade, P., Comini, P., Crivelli, P., Dalkarov, O., Debu, P., Dodd, L., Douillet, A., Guellati, S., Hervieux, P. -A, Hilico, L., Indelicato, P., Janka, G., Jonsell, S., Karr, J. -P., Kim, B. H., Kim, E. S., Kim, S. K., Ko, Y., Kosinski, T., Kuroda, N., Latacz, B. M., Lee, B., Lee, H., Lee, J., Leitee, A. M. M., Leveque, K., Lim, E., Liszkay, L., Lotrus, P., Lunney, D., Manfredi, G., Mansoulie, B., Matusiak, M., Mornacchi, G., Nesvizhevsky, V., Nez, F., Niang, S., Nishi, R., Ohayon, B., Park, K., Paul, N., Perez, P., Procureur, S., Radics, B., Regenfus, C., Reymond, J. -M., Reynaud, S., Rousse, J. -Y., Rousselle, O., Rubbia, A., Rzadkiewicl, J., Sacquin, Y., Schmidt-Kaler, F., Staszczak, M., Szymczyk, K., Tanaka, T., Tuchming, B., Vallage, B., Voronin, A., van der Werf, D. P., Wolf, S., Won, D., Wronka, S., Yamazaki, Y., Yoo, K. H., Yzombard, P., and Baker, C. J.
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Physics - Plasma Physics - Abstract
We present a description of the GBAR positron (e+) trapping apparatus, which consists of a three stage Buffer Gas Trap (BGT) followed by a High Field Penning Trap (HFT), and discuss its performance. The overall goal of the GBAR experiment is to measure the acceleration of the neutral antihydrogen (H) atom in the terrestrial gravitational field by neutralising a positive antihydrogen ion (H+), which has been cooled to a low temperature, and observing the subsequent H annihilation following free fall. To produce one H+ ion, about 10^10 positrons, efficiently converted into positronium (Ps), together with about 10^7 antiprotons (p), are required. The positrons, produced from an electron linac-based system, are accumulated first in the BGT whereafter they are stacked in the ultra-high vacuum HFT, where we have been able to trap 1.4(2) x 10^9 positrons in 1100 seconds.
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- 2022
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5. Publisher Erratum: Production of antihydrogen atoms by 6 keV antiprotons through a positronium cloud
- Author
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Adrich, P., Blumer, P., Caratsch, G., Chung, M., Cladé, P., Comini, P., Crivelli, P., Dalkarov, O., Debu, P., Douillet, A., Drapier, D., Froelich, P., Garroum, N., Guellati-Khelifa, S., Guyomard, J., Hervieux, P.-A., Hilico, L., Indelicato, P., Jonsell, S., Karr, J.-P., Kim, B., Kim, S., Kim, E.-S., Ko, Y. J., Kosinski, T., Kuroda, N., Latacz, B. M., Lee, B., Lee, H., Lee, J., Lim, E., Liszkay, L., Lunney, D., Manfredi, G., Mansoulié, B., Matusiak, M., Nesvizhevsky, V., Nez, F., Niang, S., Ohayon, B., Park, K., Paul, N., Pérez, P., Regenfus, C., Reynaud, S., Roumegou, C., Roussé, J.-Y., Sacquin, Y., Sadowski, G., Sarkisyan, J., Sato, M., Schmidt-Kaler, F., Staszczak, M., Szymczyk, K., Tanaka, T. A., Tuchming, B., Vallage, B., Voronin, A., van der Werf, D. P., Welker, A., Won, D., Wronka, S., Yamazaki, Y., Yoo, K.-H., and Yzombard, P.
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- 2023
- Full Text
- View/download PDF
6. Limit on the Electric Charge of Antihydrogen
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Capra, A., Amole, C., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Butler, E., Cesar, C. L., Charlton, M., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayden, M. E., Isaac, C. A., Jonsell, S., Kurchaninov, L ., Little, A., McKenna, J. T. K., Menary, S., Napoli, S. C., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Tharp, T. D., Thompson, R. I., van der Werf, D. P., Vendeiro, Z., Wurtele, J. S., Zhmoginov, A. I., and Charman, A. E.
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Physics - Atomic Physics - Abstract
The ALPHA collaboration has successfully demonstrated the production and the confinement of cold antihydrogen, $\overline{\mathrm{H}}$. An analysis of trapping data allowed a stringent limit to be placed on the electric charge of the simplest antiatom. Charge neutrality of matter is known to a very high precision, hence a neutrality limit of $\overline{\mathrm{H}}$ provides a test of CPT invariance. The experimental technique is based on the measurement of the deflection of putatively charged $\overline{\mathrm{H}}$ in an electric field. The tendency for trapped $\overline{\mathrm{H}}$ atoms to be displaced by electrostatic fields is measured and compared to the results of a detailed simulation of $\overline{\mathrm{H}}$ dynamics in the trap. An extensive survey of the systematic errors is performed, with particular attention to those due to the silicon vertex detector, which is the device used to determine the $\overline{\mathrm{H}}$ annihilation position. The limit obtained on the charge of the $\overline{\mathrm{H}}$ atom is \mbox{$ Q = (-1.3\pm1.8\pm0.4)\times10^{-8}$}, representing the first precision measurement with $\overline{\mathrm{H}}$., Comment: 5 pages, 3 figures
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- 2021
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7. Positron production using a 9 MeV electron linac for the GBAR experiment
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Charlton, M., Choi, J. J., Chung, M., Clade, P., Comini, P., Crepin, P-P., Crivelli, P., Dalkarov, O., Debu, P., Dodd, L., Douillet, A., Guellati-Khelifa, S., Hervieux, P-A., Hilico, L., Husson, A., Indelicato, P., Janka, G., Jonsell, S., Karr, J-P., Kim, B. H., Kim, E-S., Kim, S. K., Ko, Y., Kosinski, T., Kuroda, N., Latacz, B., Lee, H., Lee, J., Leite, A. M. M., Leveque, K., Lim, E., Liszkay, L., Lotrus, P., Louvradoux, T., Lunney, D., Manfredi, G., Mansoulie, B., Matusiak, M., Mornacchi, G., Nesvizhevsky, V. V., Nez, F., Niang, S., Nishi, R., Nourbaksh, S., Park, K. H., Paul, N., Perez, P., Procureur, S., Radics, B., Regenfus, C., Rey, J-M., Reymond, J-M., Reynaud, S., Rousse, J-Y., Rousselle, O., Rubbia, A., Rzadkiewicz, J., Sacquin, Y., Schmidt-Kaler, F., Staszczak, M., Tuchming, B., Vallage, B., Voronin, A., Welker, A., van der Werf, D. P., Wolf, S., Won, D., Wronka, S., Yamazaki, Y., and Yoo, K-H.
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Physics - Instrumentation and Detectors - Abstract
For the GBAR (Gravitational Behaviour of Antihydrogen at Rest) experiment at CERN's Antiproton Decelerator (AD) facility we have constructed a source of slow positrons, which uses a low-energy electron linear accelerator (linac). The driver linac produces electrons of 9 MeV kinetic energy that create positrons from bremsstrahlung-induced pair production. Staying below 10 MeV ensures no persistent radioactive activation in the target zone and that the radiation level outside the biological shield is safe for public access. An annealed tungsten-mesh assembly placed directly behind the target acts as a positron moderator. The system produces $5\times10^7$ slow positrons per second, a performance demonstrating that a low-energy electron linac is a superior choice over positron-emitting radioactive sources for high positron flux., Comment: published in NIM A. 33 pages 9 figures
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- 2020
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8. Laser cooling of antihydrogen atoms
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Baker, CJ, Bertsche, W, Capra, A, Carruth, C, Cesar, CL, Charlton, M, Christensen, A, Collister, R, Mathad, A Cridland, Eriksson, S, Evans, A, Evetts, N, Fajans, J, Friesen, T, Fujiwara, MC, Gill, DR, Grandemange, P, Granum, P, Hangst, JS, Hardy, WN, Hayden, ME, Hodgkinson, D, Hunter, E, Isaac, CA, Johnson, MA, Jones, JM, Jones, SA, Jonsell, S, Khramov, A, Knapp, P, Kurchaninov, L, Madsen, N, Maxwell, D, McKenna, JTK, Menary, S, Michan, JM, Momose, T, Mullan, PS, Munich, JJ, Olchanski, K, Olin, A, Peszka, J, Powell, A, Pusa, P, Rasmussen, CØ, Robicheaux, F, Sacramento, RL, Sameed, M, Sarid, E, Silveira, DM, Starko, DM, So, C, Stutter, G, Tharp, TD, Thibeault, A, Thompson, RI, van der Werf, DP, and Wurtele, JS
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Quantum Physics ,Atomic ,Molecular and Optical Physics ,Physical Sciences ,General Science & Technology - Abstract
The photon-the quantum excitation of the electromagnetic field-is massless but carries momentum. A photon can therefore exert a force on an object upon collision1. Slowing the translational motion of atoms and ions by application of such a force2,3, known as laser cooling, was first demonstrated 40 years ago4,5. It revolutionized atomic physics over the following decades6-8, and it is now a workhorse in many fields, including studies on quantum degenerate gases, quantum information, atomic clocks and tests of fundamental physics. However, this technique has not yet been applied to antimatter. Here we demonstrate laser cooling of antihydrogen9, the antimatter atom consisting of an antiproton and a positron. By exciting the 1S-2P transition in antihydrogen with pulsed, narrow-linewidth, Lyman-α laser radiation10,11, we Doppler-cool a sample of magnetically trapped antihydrogen. Although we apply laser cooling in only one dimension, the trap couples the longitudinal and transverse motions of the anti-atoms, leading to cooling in all three dimensions. We observe a reduction in the median transverse energy by more than an order of magnitude-with a substantial fraction of the anti-atoms attaining submicroelectronvolt transverse kinetic energies. We also report the observation of the laser-driven 1S-2S transition in samples of laser-cooled antihydrogen atoms. The observed spectral line is approximately four times narrower than that obtained without laser cooling. The demonstration of laser cooling and its immediate application has far-reaching implications for antimatter studies. A more localized, denser and colder sample of antihydrogen will drastically improve spectroscopic11-13 and gravitational14 studies of antihydrogen in ongoing experiments. Furthermore, the demonstrated ability to manipulate the motion of antimatter atoms by laser light will potentially provide ground-breaking opportunities for future experiments, such as anti-atomic fountains, anti-atom interferometry and the creation of antimatter molecules.
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- 2021
9. Sympathetic cooling of positrons to cryogenic temperatures for antihydrogen production
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Baker, CJ, Bertsche, W, Capra, A, Cesar, CL, Charlton, M, Mathad, A Cridland, Eriksson, S, Evans, A, Evetts, N, Fabbri, S, Fajans, J, Friesen, T, Fujiwara, MC, Grandemange, P, Granum, P, Hangst, JS, Hayden, ME, Hodgkinson, D, Isaac, CA, Johnson, MA, Jones, JM, Jones, SA, Jonsell, S, Kurchaninov, L, Madsen, N, Maxwell, D, McKenna, JTK, Menary, S, Momose, T, Mullan, P, Olchanski, K, Olin, A, Peszka, J, Powell, A, Pusa, P, Rasmussen, CØ, Robicheaux, F, Sacramento, RL, Sameed, M, Sarid, E, Silveira, DM, Stutter, G, So, C, Tharp, TD, Thompson, RI, van der Werf, DP, and Wurtele, JS
- Abstract
The positron, the antiparticle of the electron, predicted by Dirac in 1931 and discovered by Anderson in 1933, plays a key role in many scientific and everyday endeavours. Notably, the positron is a constituent of antihydrogen, the only long-lived neutral antimatter bound state that can currently be synthesized at low energy, presenting a prominent system for testing fundamental symmetries with high precision. Here, we report on the use of laser cooled Be+ ions to sympathetically cool a large and dense plasma of positrons to directly measured temperatures below 7 K in a Penning trap for antihydrogen synthesis. This will likely herald a significant increase in the amount of antihydrogen available for experimentation, thus facilitating further improvements in studies of fundamental symmetries.
- Published
- 2021
10. Observation of the 1S-2P Lyman-α transition in antihydrogen.
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Ahmadi, M, Alves, BXR, Baker, CJ, Bertsche, W, Capra, A, Carruth, C, Cesar, CL, Charlton, M, Cohen, S, Collister, R, Eriksson, S, Evans, A, Evetts, N, Fajans, J, Friesen, T, Fujiwara, MC, Gill, DR, Hangst, JS, Hardy, WN, Hayden, ME, Hunter, ED, Isaac, CA, Johnson, MA, Jones, JM, Jones, SA, Jonsell, S, Khramov, A, Knapp, P, Kurchaninov, L, Madsen, N, Maxwell, D, McKenna, JTK, Menary, S, Michan, JM, Momose, T, Munich, JJ, Olchanski, K, Olin, A, Pusa, P, Rasmussen, CØ, Robicheaux, F, Sacramento, RL, Sameed, M, Sarid, E, Silveira, DM, Starko, DM, Stutter, G, So, C, Tharp, TD, Thompson, RI, van der Werf, DP, and Wurtele, JS
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General Science & Technology - Abstract
In 1906, Theodore Lyman discovered his eponymous series of transitions in the extreme-ultraviolet region of the atomic hydrogen spectrum1,2. The patterns in the hydrogen spectrum helped to establish the emerging theory of quantum mechanics, which we now know governs the world at the atomic scale. Since then, studies involving the Lyman-α line-the 1S-2P transition at a wavelength of 121.6 nanometres-have played an important part in physics and astronomy, as one of the most fundamental atomic transitions in the Universe. For example, this transition has long been used by astronomers studying the intergalactic medium and testing cosmological models via the so-called 'Lyman-α forest'3 of absorption lines at different redshifts. Here we report the observation of the Lyman-α transition in the antihydrogen atom, the antimatter counterpart of hydrogen. Using narrow-line-width, nanosecond-pulsed laser radiation, the 1S-2P transition was excited in magnetically trapped antihydrogen. The transition frequency at a field of 1.033 tesla was determined to be 2,466,051.7 ± 0.12 gigahertz (1σ uncertainty) and agrees with the prediction for hydrogen to a precision of 5 × 10-8. Comparisons of the properties of antihydrogen with those of its well-studied matter equivalent allow precision tests of fundamental symmetries between matter and antimatter. Alongside the ground-state hyperfine4,5 and 1S-2S transitions6,7 recently observed in antihydrogen, the Lyman-α transition will permit laser cooling of antihydrogen8,9, thus providing a cold and dense sample of anti-atoms for precision spectroscopy and gravity measurements10. In addition to the observation of this fundamental transition, this work represents both a decisive technological step towards laser cooling of antihydrogen, and the extension of antimatter spectroscopy to quantum states possessing orbital angular momentum.
- Published
- 2018
11. Characterization of the 1S-2S transition in antihydrogen.
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Ahmadi, M, Alves, BXR, Baker, CJ, Bertsche, W, Capra, A, Carruth, C, Cesar, CL, Charlton, M, Cohen, S, Collister, R, Eriksson, S, Evans, A, Evetts, N, Fajans, J, Friesen, T, Fujiwara, MC, Gill, DR, Hangst, JS, Hardy, WN, Hayden, ME, Isaac, CA, Johnson, MA, Jones, JM, Jones, SA, Jonsell, S, Khramov, A, Knapp, P, Kurchaninov, L, Madsen, N, Maxwell, D, McKenna, JTK, Menary, S, Momose, T, Munich, JJ, Olchanski, K, Olin, A, Pusa, P, Rasmussen, CØ, Robicheaux, F, Sacramento, RL, Sameed, M, Sarid, E, Silveira, DM, Stutter, G, So, C, Tharp, TD, Thompson, RI, van der Werf, DP, and Wurtele, JS
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Affordable and Clean Energy ,General Science & Technology - Abstract
In 1928, Dirac published an equation 1 that combined quantum mechanics and special relativity. Negative-energy solutions to this equation, rather than being unphysical as initially thought, represented a class of hitherto unobserved and unimagined particles-antimatter. The existence of particles of antimatter was confirmed with the discovery of the positron 2 (or anti-electron) by Anderson in 1932, but it is still unknown why matter, rather than antimatter, survived after the Big Bang. As a result, experimental studies of antimatter3-7, including tests of fundamental symmetries such as charge-parity and charge-parity-time, and searches for evidence of primordial antimatter, such as antihelium nuclei, have high priority in contemporary physics research. The fundamental role of the hydrogen atom in the evolution of the Universe and in the historical development of our understanding of quantum physics makes its antimatter counterpart-the antihydrogen atom-of particular interest. Current standard-model physics requires that hydrogen and antihydrogen have the same energy levels and spectral lines. The laser-driven 1S-2S transition was recently observed 8 in antihydrogen. Here we characterize one of the hyperfine components of this transition using magnetically trapped atoms of antihydrogen and compare it to model calculations for hydrogen in our apparatus. We find that the shape of the spectral line agrees very well with that expected for hydrogen and that the resonance frequency agrees with that in hydrogen to about 5 kilohertz out of 2.5 × 1015 hertz. This is consistent with charge-parity-time invariance at a relative precision of 2 × 10-12-two orders of magnitude more precise than the previous determination 8 -corresponding to an absolute energy sensitivity of 2 × 10-20 GeV.
- Published
- 2018
12. Antihydrogen accumulation for fundamental symmetry tests.
- Author
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Ahmadi, M, Alves, BXR, Baker, CJ, Bertsche, W, Butler, E, Capra, A, Carruth, C, Cesar, CL, Charlton, M, Cohen, S, Collister, R, Eriksson, S, Evans, A, Evetts, N, Fajans, J, Friesen, T, Fujiwara, MC, Gill, DR, Gutierrez, A, Hangst, JS, Hardy, WN, Hayden, ME, Isaac, CA, Ishida, A, Johnson, MA, Jones, SA, Jonsell, S, Kurchaninov, L, Madsen, N, Mathers, M, Maxwell, D, McKenna, JTK, Menary, S, Michan, JM, Momose, T, Munich, JJ, Nolan, P, Olchanski, K, Olin, A, Pusa, P, Rasmussen, CØ, Robicheaux, F, Sacramento, RL, Sameed, M, Sarid, E, Silveira, DM, Stracka, S, Stutter, G, So, C, Tharp, TD, Thompson, JE, Thompson, RI, van der Werf, DP, and Wurtele, JS
- Abstract
Antihydrogen, a positron bound to an antiproton, is the simplest anti-atom. Its structure and properties are expected to mirror those of the hydrogen atom. Prospects for precision comparisons of the two, as tests of fundamental symmetries, are driving a vibrant programme of research. In this regard, a limiting factor in most experiments is the availability of large numbers of cold ground state antihydrogen atoms. Here, we describe how an improved synthesis process results in a maximum rate of 10.5 ± 0.6 atoms trapped and detected per cycle, corresponding to more than an order of magnitude improvement over previous work. Additionally, we demonstrate how detailed control of electron, positron and antiproton plasmas enables repeated formation and trapping of antihydrogen atoms, with the simultaneous retention of atoms produced in previous cycles. We report a record of 54 detected annihilation events from a single release of the trapped anti-atoms accumulated from five consecutive cycles.Antihydrogen studies are important in testing the fundamental principles of physics but producing antihydrogen in large amounts is challenging. Here the authors demonstrate an efficient and high-precision method for trapping and stacking antihydrogen by using controlled plasma.
- Published
- 2017
13. An improved limit on the charge of antihydrogen from stochastic acceleration.
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Ahmadi, M, Baquero-Ruiz, M, Bertsche, W, Butler, E, Capra, A, Carruth, C, Cesar, CL, Charlton, M, Charman, AE, Eriksson, S, Evans, LT, Evetts, N, Fajans, J, Friesen, T, Fujiwara, MC, Gill, DR, Gutierrez, A, Hangst, JS, Hardy, WN, Hayden, ME, Isaac, CA, Ishida, A, Jones, SA, Jonsell, S, Kurchaninov, L, Madsen, N, Maxwell, D, McKenna, JTK, Menary, S, Michan, JM, Momose, T, Munich, JJ, Nolan, P, Olchanski, K, Olin, A, Povilus, A, Pusa, P, Rasmussen, CØ, Robicheaux, F, Sacramento, RL, Sameed, M, Sarid, E, Silveira, DM, So, C, Tharp, TD, Thompson, RI, van der Werf, DP, Wurtele, JS, and Zhmoginov, AI
- Subjects
General Science & Technology - Abstract
Antimatter continues to intrigue physicists because of its apparent absence in the observable Universe. Current theory requires that matter and antimatter appeared in equal quantities after the Big Bang, but the Standard Model of particle physics offers no quantitative explanation for the apparent disappearance of half the Universe. It has recently become possible to study trapped atoms of antihydrogen to search for possible, as yet unobserved, differences in the physical behaviour of matter and antimatter. Here we consider the charge neutrality of the antihydrogen atom. By applying stochastic acceleration to trapped antihydrogen atoms, we determine an experimental bound on the antihydrogen charge, Qe, of |Q|
- Published
- 2016
14. Production of antihydrogen atoms by 6 keV antiprotons through a positronium cloud
- Author
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Adrich, P., primary, Blumer, P., additional, Caratsch, G., additional, Chung, M., additional, Cladé, P., additional, Comini, P., additional, Crivelli, P., additional, Dalkarov, O., additional, Debu, P., additional, Douillet, A., additional, Drapier, D., additional, Froelich, P., additional, Garroum, N., additional, Guellati-Khelifa, S., additional, Guyomard, J., additional, Hervieux, P.-A., additional, Hilico, L., additional, Indelicato, P., additional, Jonsell, S., additional, Karr, J.-P., additional, Kim, B., additional, Kim, S., additional, Kim, E.-S., additional, Ko, Y. J., additional, Kosinski, T., additional, Kuroda, N., additional, Latacz, B. M., additional, Lee, B., additional, Lee, H., additional, Lee, J., additional, Lim, E., additional, Liszkay, L., additional, Lunney, D., additional, Manfredi, G., additional, Mansoulié, B., additional, Matusiak, M., additional, Nesvizhevsky, V., additional, Nez, F., additional, Niang, S., additional, Ohayon, B., additional, Park, K., additional, Paul, N., additional, Pérez, P., additional, Regenfus, C., additional, Reynaud, S., additional, Roumegou, C., additional, Roussé, J.-Y., additional, Sacquin, Y., additional, Sadowski, G., additional, Sarkisyan, J., additional, Sato, M., additional, Schmidt-Kaler, F., additional, Staszczak, M., additional, Szymczyk, K., additional, Tanaka, T. A., additional, Tuchming, B., additional, Vallage, B., additional, Voronin, A., additional, van der Werf, D. P., additional, Welker, A., additional, Won, D., additional, Wronka, S., additional, Yamazaki, Y., additional, Yoo, K.-H., additional, and Yzombard, P., additional
- Published
- 2023
- Full Text
- View/download PDF
15. In situ electromagnetic field diagnostics with an electron plasma in a Penning-Malmberg trap
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Amole, C., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Butler, E., Capra, A., Cesar, C. L., Charlton, M., Deller, A., Evetts, N., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayden, M. E., Isaac, C. A., Jonsell, S., Kurchaninov, L., Little, A., Madsen, N., McKenna, J. T. K., Menary, S., Napoli, S. C., Olchanski, K., Olin, A., Pusa, P., Rasmussen, C. Ø., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Stracka, S., Tharp, T., Thompson, R. I., van der Werf, D. P., and Wurtele, J. S.
- Subjects
Physics - Plasma Physics ,Nuclear Experiment ,Physics - Atomic Physics - Abstract
We demonstrate a novel detection method for the cyclotron resonance frequency of an electron plasma in a Penning-Malmberg trap. With this technique, the electron plasma is used as an in situ diagnostic tool for measurement of the static magnetic field and the microwave electric field in the trap. The cyclotron motion of the electron plasma is excited by microwave radiation and the temperature change of the plasma is measured non-destructively by monitoring the plasma's quadrupole mode frequency. The spatially-resolved microwave electric field strength can be inferred from the plasma temperature change and the magnetic field is found through the cyclotron resonance frequency. These measurements were used extensively in the recently reported demonstration of resonant quantum interactions with antihydrogen.
- Published
- 2014
- Full Text
- View/download PDF
16. Antihydrogen and mirror-trapped antiproton discrimination: Discriminating between antihydrogen and mirror-trapped antiprotons in a minimum-B trap
- Author
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Amole, C., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Deller, A., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayden, M. E., Humphries, A. J., Hydomako, R., Kurchaninov, L., Jonsell, S., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., and Wurtele, J. S.
- Subjects
Physics - Atomic Physics ,High Energy Physics - Experiment ,Nuclear Experiment ,Physics - Plasma Physics - Abstract
Recently, antihydrogen atoms were trapped at CERN in a magnetic minimum (minimum-B) trap formed by superconducting octupole and mirror magnet coils. The trapped antiatoms were detected by rapidly turning off these magnets, thereby eliminating the magnetic minimum and releasing any antiatoms contained in the trap. Once released, these antiatoms quickly hit the trap wall, whereupon the positrons and antiprotons in the antiatoms annihilated. The antiproton annihilations produce easily detected signals; we used these signals to prove that we trapped antihydrogen. However, our technique could be confounded by mirror-trapped antiprotons, which would produce seemingly-identical annihilation signals upon hitting the trap wall. In this paper, we discuss possible sources of mirror-trapped antiprotons and show that antihydrogen and antiprotons can be readily distinguished, often with the aid of applied electric fields, by analyzing the annihilation locations and times. We further discuss the general properties of antiproton and antihydrogen trajectories in this magnetic geometry, and reconstruct the antihydrogen energy distribution from the measured annihilation time history., Comment: 17 figures
- Published
- 2012
- Full Text
- View/download PDF
17. Confinement of antihydrogen for 1000 seconds
- Author
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ALPHA Collaboration, Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Butler, E., Cesar, C. L., Deller, A., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayano, R. S., Hayden, M. E., Humphries, A. J., Hydomako, R., Jonsell, S., Kemp, S., Kurchaninov, L., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Pusa, P., Rasmussen, C. Ø., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., and Yamazaki, Y.
- Subjects
Physics - Atomic Physics ,High Energy Physics - Experiment ,High Energy Physics - Phenomenology ,Nuclear Experiment ,Physics - Plasma Physics - Abstract
Atoms made of a particle and an antiparticle are unstable, usually surviving less than a microsecond. Antihydrogen, made entirely of antiparticles, is believed to be stable, and it is this longevity that holds the promise of precision studies of matter-antimatter symmetry. We have recently demonstrated trapping of antihydrogen atoms by releasing them after a confinement time of 172 ms. A critical question for future studies is: how long can anti-atoms be trapped? Here we report the observation of anti-atom confinement for 1000 s, extending our earlier results by nearly four orders of magnitude. Our calculations indicate that most of the trapped anti-atoms reach the ground state. Further, we report the first measurement of the energy distribution of trapped antihydrogen which, coupled with detailed comparisons with simulations, provides a key tool for the systematic investigation of trapping dynamics. These advances open up a range of experimental possibilities, including precision studies of CPT symmetry and cooling to temperatures where gravitational effects could become apparent., Comment: 30 pages, 4 figures
- Published
- 2011
- Full Text
- View/download PDF
18. Centrifugal separation and equilibration dynamics in an electron-antiproton plasma
- Author
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Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Deller, A., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayden, M. E., Humphries, A. J., Hydomako, R., Jonsell, S., Madsen, N., Menary, S., Nolan, P., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., and Yamazaki, Y.
- Subjects
Physics - Plasma Physics ,High Energy Physics - Experiment ,Physics - Atomic Physics - Abstract
Charges in cold, multiple-species, non-neutral plasmas separate radially by mass, forming centrifugally-separated states. Here, we report the first detailed measurements of such states in an electron-antiproton plasma, and the first observations of the separation dynamics in any centrifugally-separated system. While the observed equilibrium states are expected and in agreement with theory, the equilibration time is approximately constant over a wide range of parameters, a surprising and as yet unexplained result. Electron-antiproton plasmas play a crucial role in antihydrogen trapping experiments.
- Published
- 2011
- Full Text
- View/download PDF
19. Alpha Antihydrogen Experiment
- Author
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ALPHA Collaboration, Fujiwara, M. C., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bray, C. C., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Fajans, J., Friesen, T., Gill, D. R., Hangst, J. S., Hardy, W. N., Hayano, R. S., Hayden, M. E., Humphries, A. J., Hydomako, R., Jonsell, S., Kurchaninov, L., Lambo, R., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wilding, D., Wurtele, J. S., and Yamazaki, Y.
- Subjects
Nuclear Experiment ,High Energy Physics - Experiment ,High Energy Physics - Phenomenology ,Physics - Atomic Physics ,Physics - Plasma Physics - Abstract
ALPHA is an experiment at CERN, whose ultimate goal is to perform a precise test of CPT symmetry with trapped antihydrogen atoms. After reviewing the motivations, we discuss our recent progress toward the initial goal of stable trapping of antihydrogen, with some emphasis on particle detection techniques., Comment: Invited talk presented at the Fifth Meeting on CPT and Lorentz Symmetry, Bloomington, Indiana, June 28-July 2, 2010
- Published
- 2011
20. Experimental measurement of efficiency and transport coherence of a cold atom Brownian motor in optical lattices
- Author
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Zelan, M., Hagman, H., Labaigt, G., Jonsell, S., and Dion, C. M.
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Condensed Matter - Statistical Mechanics ,Physics - Atomic Physics ,Physics - Biological Physics - Abstract
The rectification of noise into directed movement or useful energy is utilized by many different systems. The peculiar nature of the energy source and conceptual differences between such Brownian motor systems makes a characterization of the performance far from straightforward. In this work, where the Brownian motor consists of atoms interacting with dissipative optical lattices, we adopt existing theory and present experimental measurements for both the efficiency and the transport coherence. We achieve up to 0.3% for the efficiency and 0.01 for the P\'eclet number.
- Published
- 2011
- Full Text
- View/download PDF
21. Evaporative Cooling of Antiprotons to Cryogenic Temperatures
- Author
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ALPHA Collaboration, Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Hangst, J. S., Hardy, W. N., Hayano, R. S., Hayden, M. E., Humphries, A., Hydomako, R., Jonsell, S., Kurchaninov, L., Lambo, R., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wilding, D., Wurtele, J. S., and Yamazaki, Y.
- Subjects
Physics - Plasma Physics ,High Energy Physics - Experiment ,Nuclear Experiment ,Physics - Accelerator Physics ,Physics - Atomic Physics - Abstract
We report the application of evaporative cooling to clouds of trapped antiprotons, resulting in plasmas with measured temperature as low as 9~K. We have modeled the evaporation process for charged particles using appropriate rate equations. Good agreement between experiment and theory is observed, permitting prediction of cooling efficiency in future experiments. The technique opens up new possibilities for cooling of trapped ions and is of particular interest in antiproton physics, where a precise \emph{CPT} test on trapped antihydrogen is a long-standing goal., Comment: 5 pages, 4 figures
- Published
- 2010
- Full Text
- View/download PDF
22. An experimental limit on the charge of antihydrogen.
- Author
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Amole, C, Ashkezari, MD, Baquero-Ruiz, M, Bertsche, W, Butler, E, Capra, A, Cesar, CL, Charlton, M, Eriksson, S, Fajans, J, Friesen, T, Fujiwara, MC, Gill, DR, Gutierrez, A, Hangst, JS, Hardy, WN, Hayden, ME, Isaac, CA, Jonsell, S, Kurchaninov, L, Little, A, Madsen, N, McKenna, JTK, Menary, S, Napoli, SC, Nolan, P, Olchanski, K, Olin, A, Povilus, A, Pusa, P, Rasmussen, CØ, Robicheaux, F, Sarid, E, Silveira, DM, So, C, Tharp, TD, Thompson, RI, van der Werf, DP, Vendeiro, Z, Wurtele, JS, Zhmoginov, AI, and Charman, AE
- Abstract
The properties of antihydrogen are expected to be identical to those of hydrogen, and any differences would constitute a profound challenge to the fundamental theories of physics. The most commonly discussed antiatom-based tests of these theories are searches for antihydrogen-hydrogen spectral differences (tests of CPT (charge-parity-time) invariance) or gravitational differences (tests of the weak equivalence principle). Here we, the ALPHA Collaboration, report a different and somewhat unusual test of CPT and of quantum anomaly cancellation. A retrospective analysis of the influence of electric fields on antihydrogen atoms released from the ALPHA trap finds a mean axial deflection of 4.1 ± 3.4 mm for an average axial electric field of 0.51 V mm(-1). Combined with extensive numerical modelling, this measurement leads to a bound on the charge Qe of antihydrogen of Q=(-1.3 ± 1.1 ± 0.4) × 10(-8). Here, e is the unit charge, and the errors are from statistics and systematic effects.
- Published
- 2014
23. In situ electromagnetic field diagnostics with an electron plasma in a Penning–Malmberg trap
- Author
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Amole, C, Ashkezari, MD, Baquero-Ruiz, M, Bertsche, W, Butler, E, Capra, A, Cesar, CL, Charlton, M, Deller, A, Evetts, N, Eriksson, S, Fajans, J, Friesen, T, Fujiwara, MC, Gill, DR, Gutierrez, A, Hangst, JS, Hardy, WN, Hayden, ME, Isaac, CA, Jonsell, S, Kurchaninov, L, Little, A, Madsen, N, McKenna, JTK, Menary, S, Napoli, SC, Olchanski, K, Olin, A, Pusa, P, Rasmussen, CØ, Robicheaux, F, Sarid, E, Silveira, DM, So, C, Stracka, S, Tharp, T, Thompson, RI, van der Werf, DP, and Wurtele, JS
- Subjects
physics.plasm-ph ,nucl-ex ,physics.atom-ph ,Physical Sciences ,Fluids & Plasmas - Abstract
We demonstrate a novel detection method for the cyclotron resonance frequency of an electron plasma in a Penning-Malmberg trap. With this technique, the electron plasma is used as an in situ diagnostic tool for the measurement of the static magnetic field and the microwave electric field in the trap. The cyclotron motion of the electron plasma is excited by microwave radiation and the temperature change of the plasma is measured non-destructively by monitoring the plasma's quadrupole mode frequency. The spatially resolved microwave electric field strength can be inferred from the plasma temperature change and the magnetic field is found through the cyclotron resonance frequency. These measurements were used extensively in the recently reported demonstration of resonant quantum interactions with antihydrogen. © 2014 IOP Publishing and Deutsche Physikalische Gesellschaft.
- Published
- 2014
24. The ALPHA antihydrogen trapping apparatus
- Author
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Amole, C, Andresen, GB, Ashkezari, MD, Baquero-Ruiz, M, Bertsche, W, Bowe, PD, Butler, E, Capra, A, Carpenter, PT, Cesar, CL, Chapman, S, Charlton, M, Deller, A, Eriksson, S, Escallier, J, Fajans, J, Friesen, T, Fujiwara, MC, Gill, DR, Gutierrez, A, Hangst, JS, Hardy, WN, Hayano, RS, Hayden, ME, Humphries, AJ, Hurt, JL, Hydomako, R, Isaac, CA, Jenkins, MJ, Jonsell, S, Jørgensen, LV, Kerrigan, SJ, Kurchaninov, L, Madsen, N, Marone, A, McKenna, JTK, Menary, S, Nolan, P, Olchanski, K, Olin, A, Parker, B, Povilus, A, Pusa, P, Robicheaux, F, Sarid, E, Seddon, D, Nasr, S Seif El, Silveira, DM, So, C, Storey, JW, Thompson, RI, Thornhill, J, Wells, D, van der Werf, DP, Wurtele, JS, Yamazaki, Y, and Collaboration, ALPHA
- Subjects
Antihydrogen ,Antiprotons ,Positrons ,Neutral atom trap ,Microwaves ,Silicon Vertex Detector ,Astronomical and Space Sciences ,Atomic ,Molecular ,Nuclear ,Particle and Plasma Physics ,Other Physical Sciences ,Nuclear & Particles Physics - Abstract
The ALPHA collaboration, based at CERN, has recently succeeded in confining cold antihydrogen atoms in a magnetic minimum neutral atom trap and has performed the first study of a resonant transition of the anti-atoms. The ALPHA apparatus will be described herein, with emphasis on the structural aspects, diagnostic methods and techniques that have enabled antihydrogen trapping and experimentation to be achieved. © 2013 Elsevier B.V.
- Published
- 2014
25. Simulations of Sisyphus cooling including multiple excited states
- Author
-
Svensson, F., Jonsell, S., and Dion, C. M.
- Subjects
Physics - Atomic Physics - Abstract
We extend the theory for laser cooling in a near-resonant optical lattice to include multiple excited hyperfine states. Simulations are performed treating the external degrees of freedom of the atom, i.e., position and momentum, classically, while the internal atomic states are treated quantum mechanically, allowing for arbitrary superpositions. Whereas theoretical treatments including only a single excited hyperfine state predict that the temperature should be a function of lattice depth only, except close to resonance, experiments have shown that the minimum temperature achieved depends also on the detuning from resonance of the lattice light. Our results resolve this discrepancy., Comment: 7 pages, 6 figures
- Published
- 2008
- Full Text
- View/download PDF
26. Characterisation of a three-dimensional Brownian motor in optical lattices
- Author
-
Sjolund, P., Petra, S. J. H., Dion, C. M., Hagman, H., Jonsell, S., and Kastberg, A.
- Subjects
Physics - Atomic Physics - Abstract
We present here a detailed study of the behaviour of a three dimensional Brownian motor based on cold atoms in a double optical lattice [P. Sjolund et al., Phys. Rev. Lett. 96, 190602 (2006)]. This includes both experiments and numerical simulations of a Brownian particle. The potentials used are spatially and temporally symmetric, but combined spatiotemporal symmetry is broken by phase shifts and asymmetric transfer rates between potentials. The diffusion of atoms in the optical lattices is rectified and controlled both in direction and speed along three dimensions. We explore a large range of experimental parameters, where irradiances and detunings of the optical lattice lights are varied within the dissipative regime. Induced drift velocities in the order of one atomic recoil velocity have been achieved., Comment: 8 pages, 14 figures
- Published
- 2007
- Full Text
- View/download PDF
27. Low-temperature antihydrogen-atom scattering
- Author
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Jonsell, S
- Subjects
Physics - Atomic Physics - Abstract
A simple method to include the strong force in atom-antiatom scattering is presented. It is based on the strong-force scatteringn length between the nucleon and antinucleon. Using this method elastic and annihilation cross sections are calculated for hydrogen-antihydrogen and helium-antihydrogen scattering. The results are compared to first-order perturbation theory using a pseudo potential. The pseudo-potential approach works fairly well for hydrogen-antihydrogen scattering, but fails for helium-antihydrogen scattering where strong-force effects are more prominent., Comment: 9 pages, 2 figures, to be published in Nuclear Instruments and Methods B
- Published
- 2005
- Full Text
- View/download PDF
28. A nonadiabatic semi-classical method for dynamics of atoms in optical lattices
- Author
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Jonsell, S., Dion, C. M., Nylén, M., Petra, S. J. H., Sjölund, P., and Kastberg, A.
- Subjects
Physics - Atomic Physics - Abstract
We develop a semi-classical method to simulate the motion of atoms in a dissipative optical lattice. Our method treats the internal states of the atom quantum mechanically, including all nonadiabatic couplings, while position and momentum are treated as classical variables. We test our method in the one-dimensional case. Excellent agreement with fully quantum mechanical simulations is found. Our results are much more accurate than those of earlier semi-classical methods based on the adiabatic approximation., Comment: 7 pages, 5 figures, submitted to European Physical Journal D
- Published
- 2005
- Full Text
- View/download PDF
29. Description and first application of a new technique to measure the gravitational mass of antihydrogen
- Author
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Amole, C., Ashkezari, M. D, Baquero-Ruiz, M., Bertsche, W., Butler, E., Capra, A., Cesar, C. L, Charlton, M., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M. C, Gill, D. R, Gutierrez, A., Hangst, J. S, Hardy, W. N, Hayden, M. E, Isaac, C. A, Jonsell, S., Kurchaninov, L., Little, A., Madsen, N., McKenna, J. T. K, Menary, S., Napoli, S. C, Nolan, P., Olin, A., Pusa, P., Rasmussen, C. Ø, Robicheaux, F., Sarid, E., Silveira, D. M, So, C., Thompson, R. I, van der Werf, D. P, Wurtele, J. S, Zhmoginov, A. I, and Charman, A. E
- Subjects
BRII recipient: Fajans - Abstract
Physicists have long wondered whether the gravitational interactions between matter and antimatter might be different from those between matter and itself. Although there are many indirect indications that no such differences exist and that the weak equivalence principle holds, there have been no direct, free-fall style, experimental tests of gravity on antimatter. Here we describe a novel direct test methodology; we search for a propensity for antihydrogen atoms to fall downward when released from the ALPHA antihydrogen trap. In the absence of systematic errors, we can reject ratios of the gravitational to inertial mass of antihydrogen >75 at a statistical significance level of 5%; worst-case systematic errors increase the minimum rejection ratio to 110. A similar search places somewhat tighter bounds on a negative gravitational mass, that is, on antigravity. This methodology, coupled with ongoing experimental improvements, should allow us to bound the ratio within the more interesting near equivalence regime.
- Published
- 2013
30. The few-body problem for trapped bosons with large scattering length
- Author
-
Jonsell, S., Heiselberg, H., and Pethick, C. J.
- Subjects
Condensed Matter - Abstract
We calculate energy levels of two and three bosons trapped in a harmonic oscillator potential with oscillator length $a_{\mathrm osc}$. The atoms are assumed to interact through a short-range potential with a scattering length $a$, and the short-distance behavior of the three-body wave function is characterized by a parameter $\theta$. For large positive $a/a_{\mathrm osc}$, the energies of states which, in the absence of the trap, correspond to three free atoms approach values independent of $a$ and $\theta$. For other states the $\theta$ dependence of the energy is strong, but the energy is independent of $a$ for $|a/a_{\mathrm osc}|\gg1$., Comment: 4 pages, 3 figures
- Published
- 2002
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- View/download PDF
31. Production of antihydrogen atoms by 6 keV antiprotons through a positronium cloud
- Author
-
Adrich, P, Blumer, P, Caratsch, G, Chung, M, Cladé, P, Comini, P, Crivelli, P, Dalkarov, O, Debu, P, Douillet, A, Drapier, D, Froelich, P, Garroum, N, Guellati-Khelifa, S, Guyomard, J, Hervieux, P-A, Hilico, L, Indelicato, P, Jonsell, S, Karr, J-P, Kim, B, Kim, S, Kim, E-S, Ko, Y.J, Kosinski, T, Kuroda, N, Latacz, B.M, Lee, B, Lee, H, Lee, J, Lim, E, Liszkay, L, Lunney, D, Manfredi, G, Mansoulié, B, Matusiak, M, Nesvizhevsky, V, Nez, F, Niang, S, Ohayon, B, Park, K, Paul, N, Pérez, P, Regenfus, C, Reynaud, S, Roumegou, C, Roussé, J-Y, Sacquin, Y, Sadowski, G, Sarkisyan, J, Sato, M, Schmidt-Kaler, F, Staszczak, M, Szymczyk, K, Tanaka, T.A, Tuchming, B, Vallage, B, Voronin, A, van der Werf, D.P, Won, D, Wronka, S, Yamazaki, Y, Yoo, K-H, Yzombard, P, Laboratoire Kastler Brossel (LKB [Collège de France]), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF (institution))-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Université d'Évry-Val-d'Essonne (UEVE), Conservatoire National des Arts et Métiers [CNAM] (CNAM), HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM), Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Institut Laue-Langevin (ILL)
- Subjects
antihydrogen, production ,CERN Lab ,Physics - Instrumentation and Detectors ,background ,anti-p, beam ,positron, beam ,atom ,FOS: Physical sciences ,Instrumentation and Detectors (physics.ins-det) ,antihydrogen, beam ,charge exchange ,High Energy Physics - Experiment ,High Energy Physics - Experiment (hep-ex) ,positronium, target ,electron, linear accelerator ,[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex] ,cloud ,[PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det] - Abstract
International audience; We report on the first production of an antihydrogen beam by charge exchange of 6.1 keV antiprotons with a cloud of positronium in the GBAR experiment at CERN. The antiproton beam was delivered by the AD/ELENA facility. The positronium target was produced from a positron beam itself obtained from an electron linear accelerator. We observe an excess over background indicating antihydrogen production with a significance of 3-4 standard deviations.
- Published
- 2023
32. AD-7/GBAR status report for the 2023 CERN SPSC
- Author
-
Lunney, D, Roumegou, C, Blumer, P, Caratsch, G, Crivelli, P, Ohayon, B, Regenfus, C, Sarkisyan, J, Nesvizhevsky, V, Sacquin, Y, Vallage, B, Liszkay, L, Debu, P, Comini, P, Roussé, J-Y, Tuchming, B, Mansoulié, B, Niang, S, Pérez, P, Sadowski, G, Schmidt-Kaler, F, Indelicato, P, Drapier, D, Guellati, S, Hilico, L, Cladé, P, Douillet, A, Karr, J-P, Nez, F, Yzombard, P, Paul, N, Reynaud, S, van der Werf, DP, Jonsell, S, Froelich, P, Kim, B, Kim, S, Lee, B, Lee, H, Park, K, Won, D, Lee, J, Ko, Y, Kim, E-S, Lim, E, Chung, M, Yoo, K-H, Hervieux, P-A, Manfredi, G, Yamazaki, Y, Kuroda, N, Tanaka, T, Sato, M, Kosinski, T, Matusiak, M, Staszczak, M, Wronka, S, Adrich, P, and Szymczyk, K
- Subjects
Detectors and Experimental Techniques - Abstract
We report on the activities performed during 2022 and the plans for 2023 for the GBAR experiment.
- Published
- 2023
33. Observation of the hyperfine spectrum of antihydrogen
- Author
-
Ahmadi, M., Alves, B. X. R., Baker, C. J., Bertsche, W., Butler, E., Capra, A., Carruth, C., Cesar, C. L., Charlton, M., Cohen, S., Collister, R., Eriksson, S., Evans, A., Evetts, N., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayden, M. E., Isaac, C. A., Ishida, A., Johnson, M. A., Jones, S. A., Jonsell, S., Kurchaninov, L., Madsen, N., Mathers, M., Maxwell, D., McKenna, J. T. K., Menary, S., Michan, J. M., Momose, T., Munich, J. J., Nolan, P., Olchanski, K., Olin, A., Pusa, P., Rasmussen, C. ., Robicheaux, F., Sacramento, R. L., Sameed, M., Sarid, E., Silveira, D. M., Stracka, S., Stutter, G., So, C., Tharp, T. D., Thompson, J. E., Thompson, R. I., van der Werf, D. P., and Wurtele, J. S.
- Subjects
Antimatter -- Observations ,Hydrogen -- Observations ,Environmental issues ,Science and technology ,Zoology and wildlife conservation - Abstract
Author(s): M. Ahmadi [1]; B. X. R. Alves [2]; C. J. Baker [3]; W. Bertsche [4, 5]; E. Butler [6]; A. Capra [7]; C. Carruth [8]; C. L. Cesar [9]; [...]
- Published
- 2017
- Full Text
- View/download PDF
34. Observation of the 1S2S transition in trapped antihydrogen
- Author
-
Ahmadi, M., Alves, B. X. R., Baker, C. J., Bertsche, W., Butler, E., Capra, A., Carruth, C., Cesar, C. L., Charlton, M., Cohen, S., Collister, R., Eriksson, S., Evans, A., Evetts, N., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayden, M. E., Isaac, C. A., Ishida, A., Johnson, M. A., Jones, S. A., Jonsell, S., Kurchaninov, L., Madsen, N., Mathers, M., Maxwell, D., McKenna, J. T. K., Menary, S., Michan, J. M., Momose, T., Munich, J. J., Nolan, P., Olchanski, K., Olin, A., Pusa, P., Rasmussen, C. ., Robicheaux, F., Sacramento, R. L., Sameed, M., Sarid, E., Silveira, D. M., Stracka, S., Stutter, G., So, C., Tharp, T. D., Thompson, J. E., Thompson, R. I., van der Werf, D. P., and Wurtele, J. S.
- Subjects
Phase transitions (Physics) -- Observations ,Antimatter -- Properties ,Environmental issues ,Science and technology ,Zoology and wildlife conservation - Abstract
Author(s): M. Ahmadi [1]; B. X. R. Alves [2]; C. J. Baker [3]; W. Bertsche [4, 5]; E. Butler [6]; A. Capra [7]; C. Carruth [8]; C. L. Cesar [9]; [...]
- Published
- 2017
- Full Text
- View/download PDF
35. Observation of the 1S–2S transition in trapped antihydrogen
- Author
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Ahmadi, M., Alves, B. X. R., Baker, C. J., Bertsche, W., Butler, E., Capra, A., Carruth, C., Cesar, C. L., Charlton, M., Cohen, S., Collister, R., Eriksson, S., Evans, A., Evetts, N., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayden, M. E., Isaac, C. A., Ishida, A., Johnson, M. A., Jones, S. A., Jonsell, S., Kurchaninov, L., Madsen, N., Mathers, M., Maxwell, D., McKenna, J. T. K., Menary, S., Michan, J. M., Momose, T., Munich, J. J., Nolan, P., Olchanski, K., Olin, A., Pusa, P., Rasmussen, C. Ø., Robicheaux, F., Sacramento, R. L., Sameed, M., Sarid, E., Silveira, D. M., Stracka, S., Stutter, G., So, C., Tharp, T. D., Thompson, J. E., Thompson, R. I., van der Werf, D. P., and Wurtele, J. S.
- Published
- 2017
- Full Text
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36. Erratum: Observation of the hyperfine spectrum of antihydrogen
- Author
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Ahmadi, M., Alves, B. X. R., Baker, C. J., Bertsche, W., Butler, E., Capra, A., Carruth, C., Cesar, C. L., Charlton, M., Cohen, S., Collister, R., Eriksson, S., Evans, A., Evetts, N., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayden, M. E., Isaac, C. A., Ishida, A., Johnson, M. A., Jones, S. A., Jonsell, S., Kurchaninov, L., Madsen, N., Mathers, M., Maxwell, D., McKenna, J. T. K., Menary, S., Michan, J. M., Momose, T., Munich, J. J., Nolan, P., Olchanski, K., Olin, A., Pusa, P., Rasmussen, C. ., Robicheaux, F., Sacramento, R. L., Sameed, M., Sarid, E., Silveira, D. M., Stracka, S., Stutter, G., So, C., Tharp, T. D., Thompson, J. E., Thompson, R. I., van der Werf, D. P., and Wurtele, J. S.
- Subjects
Environmental issues ,Science and technology ,Zoology and wildlife conservation - Abstract
Author(s): M. Ahmadi; B. X. R. Alves; C. J. Baker; W. Bertsche; E. Butler; A. Capra; C. Carruth; C. L. Cesar; M. Charlton; S. Cohen; R. Collister; S. Eriksson; A. [...]
- Published
- 2018
- Full Text
- View/download PDF
37. On the binding energies of antihydrogen formed by the interactions of antiprotons in cold positron plasmas
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Jonsell, S, primary and Charlton, M, additional
- Published
- 2021
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38. Investigation of the fine structure of antihydrogen
- Author
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Ahmadi, M, Alves, BXR, Baker, CJ, Bertsche, W, Capra, A, Carruth, C, Cesar, CL, Charlton, M, Cohen, S, Collister, R, Eriksson, S, Evans, A, Evetts, N, Fajans, J, Friesen, T, Fujiwara, MC, Gill, DR, Granum, P, Hangst, JS, Hardy, WN, Hayden, ME, Hunter, ED, Isaac, CA, Johnson, MA, Jones, JM, Jones, SA, Jonsell, S, Khramov, A, Knapp, P, Kurchaninov, L, Madsen, N, Maxwell, D, McKenna, JTK, Menary, S, Michan, JM, Momose, T, Munich, JJ, Olchanski, K, Olin, A, Pusa, P, Rasmussen, CO, Robicheaux, F, Sacramento, RL, Sameed, M, Sarid, E, Silveira, DM, So, C, Starko, DM, Stutter, G, Tharp, TD, Thompson, RI, van der Werf, DP, Wurtele, JS, Collaboration, ALPHA, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, and ALPHA
- Subjects
Physics::General Physics ,experimental methods ,p: charge distribution ,magnetic field ,size ,01 natural sciences ,Article ,spectrum ,Standard Model ,symbols.namesake ,p: size ,Quantum mechanics ,0103 physical sciences ,quantum electrodynamics ,[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex] ,Physics::Atomic Physics ,010306 general physics ,Antihydrogen ,Quantum ,fine structure ,Physics ,antihydrogen ,Multidisciplinary ,Zeeman effect ,010308 nuclear & particles physics ,precision measurement ,Charge (physics) ,3. Good health ,Lamb shift ,asymmetry: CPT ,Automatic Keywords ,Antiproton ,hydrogen ,Antimatter ,frequency ,symbols ,Exotic atoms and molecules ,Experimental particle physics ,Particle Physics - Experiment ,experimental results - Abstract
At the historic Shelter Island Conference on the Foundations of Quantum Mechanics in 1947, Willis Lamb reported an unexpected feature in the fine structure of atomic hydrogen: a separation of the 2S1/2 and 2P1/2 states1. The observation of this separation, now known as the Lamb shift, marked an important event in the evolution of modern physics, inspiring others to develop the theory of quantum electrodynamics2–5. Quantum electrodynamics also describes antimatter, but it has only recently become possible to synthesize and trap atomic antimatter to probe its structure. Mirroring the historical development of quantum atomic physics in the twentieth century, modern measurements on anti-atoms represent a unique approach for testing quantum electrodynamics and the foundational symmetries of the standard model. Here we report measurements of the fine structure in the n = 2 states of antihydrogen, the antimatter counterpart of the hydrogen atom. Using optical excitation of the 1S–2P Lyman-α transitions in antihydrogen6, we determine their frequencies in a magnetic field of 1 tesla to a precision of 16 parts per billion. Assuming the standard Zeeman and hyperfine interactions, we infer the zero-field fine-structure splitting (2P1/2–2P3/2) in antihydrogen. The resulting value is consistent with the predictions of quantum electrodynamics to a precision of 2 per cent. Using our previously measured value of the 1S–2S transition frequency6,7, we find that the classic Lamb shift in antihydrogen (2S1/2–2P1/2 splitting at zero field) is consistent with theory at a level of 11 per cent. Our observations represent an important step towards precision measurements of the fine structure and the Lamb shift in the antihydrogen spectrum as tests of the charge–parity–time symmetry8 and towards the determination of other fundamental quantities, such as the antiproton charge radius9,10, in this antimatter system., Precision measurements of the 1S–2P transition in antihydrogen that take into account the standard Zeeman and hyperfine effects confirm the predictions of quantum electrodynamics.
- Published
- 2020
39. Towards prediction of the rates of antihydrogen positive ion production in antihydrogen-excited positronium reaction
- Author
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Yamashita, T., Kino, Y., Hiyama, E., Piszczatowski, Konrad, Jonsell, S., Froelich, Piotr, Yamashita, T., Kino, Y., Hiyama, E., Piszczatowski, Konrad, Jonsell, S., and Froelich, Piotr
- Abstract
We present the 4-body calculation of the antihydrogen-positronium scattering aiming at the prediction of cross sections for the production of antihydrogen positive ions. The latter are expected to be a useful source of ultra-cold atoms for the test of matter-antimatter gravity. We convert the Schrodinger equation to a set of coupled integro-di fferential equations that involve intermediate states and are solved using the compact finite di fference method. We will present the investigation of the rearrangement reaction between the ground-state antihydrogen atom and the excited positronium.
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- 2020
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40. Towards prediction of the rates of antihydrogen positive ion production in collision of antihydrogen with excited positronium
- Author
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Yamashita, T., Kino, Y., Hiyama, E., Piszczatowski, Konrad, Jonsell, S., Froelich, Piotr, Yamashita, T., Kino, Y., Hiyama, E., Piszczatowski, Konrad, Jonsell, S., and Froelich, Piotr
- Abstract
We present a 4-body calculation of scattering between an antihydrogen atom ((H) over bar) and a positronium (Ps) aiming at the prediction of cross sections for the production of antihydrogen positive ions (($H) over bar (+)). The antihydrogen positive ions are expected to be a useful source of ultra-cold anti-atoms for the test of matter-antimatter gravity. We convert the Schrodinger equation to a set of coupled integro-differential equations that involve intermediate states which facilitate the internal region description of the scattering wavefunction. They are solved using a compact finite difference method. Our framework is extended to scattering between an excited Ps and (H) over bar. Cross sections of the reactions, Ps (1s/2s/3s) + (H) over bar -> e(-) + (H) over bar (+), in s-wave collisions, are calculated. It is found that the reactions originating from Ps (1s/2s) + H produce (H) over bar (+) with a constant cross section within 0.05 eV above the threshold while the reaction cross section from Ps (3s) decreases as the collision energy increases in the same energy interval. Just above the threshold, the cross section of (H) over bar (+) production from Ps (3s) + (H) over bar in s-wave collision is 7.8 times larger than that from Ps (1 s) + (H) over bar in s-wave and 2.3 times larger than that from Ps (2s) + (H) over bar in s-wave. The near-threshold de-excitation reaction from Ps (3s) + (H) over bar occurs more rapidly than the (H) over bar (+) production.
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- 2020
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41. Accumulation of Positrons from a LINAC Based Source
- Author
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Niang, S., primary, Charlton, M., additional, Choi, J.J., additional, Chung, M., additional, Cladé, P., additional, Comini, P., additional, Crivelli, P., additional, Crépin, P.P., additional, Dalkarov, O., additional, Debu, P., additional, Dodd, L., additional, Douillet, A., additional, Froehlich, P., additional, Gafriller, J., additional, Guellati, S., additional, Heinrich, J., additional, Hervieux, P.A., additional, Hilico, L., additional, Husson, A., additional, Indelicato, P., additional, Janka, G., additional, Jonsell, S., additional, Karr, J.P., additional, Kim, B.H., additional, Kim, E-S, additional, Kim, S.K., additional, Kleyheeg, A., additional, Ko, Y., additional, Kosinski, T., additional, Kuroda, N., additional, Latacz, B., additional, Lee, H., additional, Lee, J., additional, Leite, A.M.M., additional, Lim, E., additional, Liszkay, L., additional, Louvradoux, T., additional, Lunney, D., additional, Lévéque, K., additional, Manfredi, G., additional, Mansoulié, B., additional, Matusiak, M., additional, Mornacchi, G., additional, Nesvizhevsky, V.V., additional, Nez, F., additional, Nishi, R., additional, Nourbaksh, S., additional, Park, K.H., additional, Paul, N., additional, Pérez, P., additional, Radics, B., additional, Regenfus, C., additional, Reynaud, S., additional, Roussé, J.Y., additional, Rubbia, A., additional, Rzadkiewicz, J., additional, Sacquin, Y., additional, Schmidt-Kaler, F., additional, Staszczak, M., additional, Tuchming, B., additional, Vallage, B., additional, van der Werf, D.P., additional, Voronin, A., additional, Welker, A., additional, Wolf, S., additional, Won, D., additional, Wronka, S., additional, Yamazaki, Y., additional, Yoo, K.H., additional, and Baker, C.J., additional
- Published
- 2020
- Full Text
- View/download PDF
42. Development of a PbWO4 Detector for Single-Shot Positron Annihilation Lifetime Spectroscopy at the GBAR Experiment
- Author
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Kim, B.H., primary, Choi, J.J., additional, Chung, M., additional, Cladé, P., additional, Comini, P., additional, Crivelli, P., additional, Crépin, P-P, additional, Dalkarov, O., additional, Debu, P., additional, Dodd, L., additional, Douillet, A., additional, Froehlich, P., additional, Guellati, S., additional, Heinrich, J., additional, Hervieux, P.A., additional, Hilico, L., additional, Husson, A., additional, Indelicato, P., additional, Janka, G., additional, Jonsell, S., additional, Karr, J.P., additional, Kim, E.S., additional, Kim, S.K., additional, Ko, Y., additional, Kosinski, T., additional, Kuroda, N., additional, Latacz, B., additional, Lee, H., additional, Lee, J., additional, Leite, A.M.M., additional, Lim, E., additional, Liszkay, L., additional, Louvradoux, T., additional, Lunney, D., additional, Lévêque, K., additional, Manfredi, G., additional, Mansoulié, B., additional, Matusiak, M., additional, Mornacchi, G., additional, Nesvizhevsky, V.V., additional, Nez, F., additional, Niang, S., additional, Nishi, R., additional, Nourbaksh, S., additional, Lotrus, P., additional, Park, K.H., additional, Paul, N., additional, Pérez, P., additional, Radics, B., additional, Regenfus, C., additional, Reynaud, S., additional, Roussé, J.Y., additional, Rubbia, A., additional, Rzadkiewicz, J., additional, Sacquin, Y., additional, Schmidt-Kaler, F., additional, Staszczak, M., additional, Tuchming, B., additional, Vallage, B., additional, van der Werf, D.P., additional, Voronin, A., additional, Welker, A., additional, Wolf, S., additional, Won, D., additional, Wronka, S., additional, Yamazaki, Y., additional, and Yoo, K.H., additional
- Published
- 2020
- Full Text
- View/download PDF
43. Towards prediction of the rates of antihydrogen positive ion production in collision of antihydrogen with excited positronium
- Author
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Yamashita, T, primary, Kino, Y, additional, Hiyama, E, additional, Piszczatowski, K, additional, Jonsell, S, additional, and Froelich, P, additional
- Published
- 2020
- Full Text
- View/download PDF
44. Towards prediction of the rates of antihydrogen positive ion production in antihydrogen-excited positronium reaction
- Author
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Yamashita, T, primary, Kino, Y, additional, Hiyama, E, additional, Piszczatowski, K, additional, Jonsell, S, additional, and Froelich, P, additional
- Published
- 2020
- Full Text
- View/download PDF
45. Trapped antihydrogen
- Author
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Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Deller, A., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayden, M. E., Humphries, A. J., Hydomako, R., Jenkins, M. J., Jonsell, S., Jørgensen, L. V., Kurchaninov, L., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Nasr, S. Seif el, Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., and Yamazaki, Y.
- Published
- 2010
- Full Text
- View/download PDF
46. Including the strong nuclear force in antihydrogen-scattering calculations
- Author
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Jonsell, S, Saenz, A, Froelich, P, Zygelman, B, and Dalgarno, A
- Published
- 2005
47. Machine learning for antihydrogen detection at ALPHA
- Author
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Capra, A, Ahmadi, M, Alves, BXR, Baker, CJ, Bertsche, WA, Butler, E, Carruth, C, Cesar, CL, Charlton, M, Cohen, S, Collister, RA, Eriksson, S, Evans, A, Evetts, NA, Fajans, J, Friesen, T, Fujiwara, MC, Gill, DR, Gutierrez, A, Hangst, JS, Hardy, WN, Hayden, ME, Isaac, CA, Ishida, A, Johnson, MA, Jones, SA, Jonsell, S, Kurchaninov, L, Madsen, N, Mathers, MR, Maxwell, D, McKenna, JTK, Menary, S, Michan, JM, Momose, T, Munich, JJ, Nolan, P, Olchanski, K, Olin, A, Pusa, P, Rasmussen, CO, Robicheaux, F, Sacramento, RL, Sameed, M, Sarid, E, Silveira, DM, Stracka, S, So, C, Stutter, G, Tharp, TD, Thompson, JE, Thompson, RI, van der Werf, DP, Wurtele, JS, IOP, and Collaboration, ALPHA
- Subjects
Physics ,History ,Particle physics ,010308 nuclear & particles physics ,0103 physical sciences ,Alpha (ethology) ,010306 general physics ,Antihydrogen ,01 natural sciences ,Computer Science Applications ,Education ,Computing and Computers - Abstract
The ALPHA experiment at CERN is designed to produce and trap antihydrogen to the purpose of making a precise comparison with hydrogen. The basic technique consists of driving an antihydrogen resonance which will cause the antiatom to leave the trap and annihilate. The main background to antihydrogen detection is due to cosmic rays. When an experimental cycle extends for several minutes, while the number of trapped antihydrogen remains fixed, background rejection can become challenging. Machine learning methods have been employed in ALPHA for several years, leading to a dramatic reduction of the background contamination. This allowed ALPHA to perform the first laser spectroscopy experiment on antihydrogen.
- Published
- 2018
48. Formation of antihydrogen beams from positron–antiproton interactions
- Author
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Jonsell, S, primary and Charlton, M, additional
- Published
- 2019
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- View/download PDF
49. Trapped antihydrogen
- Author
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Butler, E., Andresen, G., Ashkezari, M., Baquero-Ruiz, M., Bertsche, W., Bowe, P., Cesar, C., Chapman, S., Charlton, M., Deller, A., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M., Gill, D., Gutierrez, A., Hangst, J., Hardy, W., Hayden, M., Humphries, A., Hydomako, R., Jenkins, M., Jonsell, S., Jørgensen, L., Kemp, S., Kurchaninov, L., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Rasmussen, C., Robicheaux, F., Sarid, E., Seif el Nasr, S., Silveira, D., So, C., Storey, J., Thompson, R., van der Werf, D., Wurtele, J., Yamazaki, Y., Butler, E., Andresen, G., Ashkezari, M., Baquero-Ruiz, M., Bertsche, W., Bowe, P., Cesar, C., Chapman, S., Charlton, M., Deller, A., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M., Gill, D., Gutierrez, A., Hangst, J., Hardy, W., Hayden, M., Humphries, A., Hydomako, R., Jenkins, M., Jonsell, S., Jørgensen, L., Kemp, S., Kurchaninov, L., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Rasmussen, C., Robicheaux, F., Sarid, E., Seif el Nasr, S., Silveira, D., So, C., Storey, J., Thompson, R., van der Werf, D., Wurtele, J., and Yamazaki, Y.
- Abstract
Precision spectroscopic comparison of hydrogen and antihydrogen holds the promise of a sensitive test of the Charge-Parity-Time theorem and matter-antimatter equivalence. The clearest path towards realising this goal is to hold a sample of antihydrogen in an atomic trap for interrogation by electromagnetic radiation. Achieving this poses a huge experimental challenge, as state-of-the-art magnetic-minimum atom traps have well depths of only ∼1T (∼0.5K for ground state antihydrogen atoms). The atoms annihilate on contact with matter and must be ‘born' inside the magnetic trap with low kinetic energies. At the ALPHA experiment, antihydrogen atoms are produced from antiprotons and positrons stored in the form of non-neutral plasmas, where the typical electrostatic potential energy per particle is on the order of electronvolts, more than 104 times the maximum trappable kinetic energy. In November 2010, ALPHA published the observation of 38 antiproton annihilations due to antihydrogen atoms that had been trapped for at least 172ms and then released—the first instance of a purely antimatter atomic system confined for any length of time (Andresen etal., Nature 468:673, 2010). We present a description of the main components of the ALPHA traps and detectors that were key to realising this result. We discuss how the antihydrogen atoms were identified and how they were discriminated from the background processes. Since the results published in Andresen etal. (Nature 468:673, 2010), refinements in the antihydrogen production technique have allowed many more antihydrogen atoms to be trapped, and held for much longer times. We have identified antihydrogen atoms that have been trapped for at least 1,000s in the apparatus (Andresen etal., Nature Physics 7:558, 2011). This is more than sufficient time to interrogate the atoms spectroscopically, as well as to ensure that they have relaxed to their ground state
- Published
- 2018
50. Development of a PbWO4 Detector for Single-Shot Positron Annihilation Lifetime Spectroscopy at the GBAR Experiment.
- Author
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KIM, B. H., CHOI, J. J., CHUNG, M., CLADÉ, P., COMINI, P., CRIVELLI, P., CRÉPIN, P-P., DALKAROV, O., DEBU, P., DODD, L., DOUILLET, A., FROEHLICH, P., GUELLATI, S., HEINRICH, J., HERVIEUXJ, P.-A., HILICO, L., HUSSON, A., INDELICATO, P., JANKA, G., and JONSELL, S.
- Subjects
POSITRON annihilation ,POSITRONIUM ,CHARGE exchange ,DETECTORS ,POSITRON beams ,SPECTROMETRY - Abstract
We have developed a PbWO
4 (PWO) detector with a large dynamic range to measure the intensity of a positron beam and the absolute density of the ortho-positronium (o-Ps) cloud it creates. A simulation study shows that a setup based on such detectors may be used to determine the angular distribution of the emission and reflection of o-Ps to reduce part of the uncertainties of the measurement. These will allow to improve the precision in the measurement of the cross-section for the (anti)hydrogen formation by (anti)proton-positronium charge exchange and to optimize the yield of antihydrogen ion which is an essential parameter in the GBAR experiment. [ABSTRACT FROM AUTHOR]- Published
- 2020
- Full Text
- View/download PDF
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