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176 results on '"Silveira, D. M."'

1. Design and Performance of a Novel Low Energy Multi-Species Beamline for the ALPHA Antihydrogen Experiment

Author

Baker, C. J., Bertsche, W., Capra, A., Cesar, C. L., Charlton, M., Christensen, A. J., Collister, R., Mathad, A. Cridland, Eriksson, S., Evans, A., Evetts, N., Fabbri, S., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Grandemange, P., Granum, P., Hangst, J. S., Hayden, M. E., Hodgkinson, D., Isaac, C. A., Johnson, M. A., Jones, J. M., Jones, S. A., Khramov, A., Kurchaninov, L., Madsen, N., Maxwell, D., McKenna, J. T. K., Menary, S., Momose, T., Mullan, P. S., Munich, J. J., Olchanski, K., Peszka, J., Powell, A., Rasmussen, C. O., Sacramento, R. L., Sameed, M., Sarid, E., Silveira, D. M., So, C., Starko, D. M., Stutter, G., Tharp, T. D., Thompson, R. I., Torkzaban, C., van der Werf, D. P., and Wurtele, J. S.

Subjects
Physics - Accelerator Physics
Abstract

The ALPHA Collaboration, based at the CERN Antiproton Decelerator, has recently implemented a novel beamline for low-energy ($\lesssim$ 100 eV) positron and antiproton transport between cylindrical Penning traps that have strong axial magnetic fields. Here, we describe how a combination of semianalytical and numerical calculations were used to optimise the layout and design of this beamline. Using experimental measurements taken during the initial commissioning of the instrument, we evaluate its performance and validate the models used for its development. By combining data from a range of sources, we show that the beamline has a high transfer efficiency, and estimate that the percentage of particles captured in the experiments from each bunch is (78 $\pm$ 3)% for up to $10^{5}$ antiprotons, and (71 $\pm$ 5)% for bunches of up to $10^{7}$ positrons., Comment: 15 pages, 15 figures

Published
2022
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2. Observation of the effect of gravity on the motion of antimatter

Author

Anderson, E. K., Baker, C. J., Bertsche, W., Bhatt, N. M., Bonomi, G., Capra, A., Carli, I., Cesar, C. L., Charlton, M., Christensen, A., Collister, R., Cridland Mathad, A., Duque Quiceno, D., Eriksson, S., Evans, A., Evetts, N., Fabbri, S., Fajans, J., Ferwerda, A., Friesen, T., Fujiwara, M. C., Gill, D. R., Golino, L. M., Gomes Gonçalves, M. B., Grandemange, P., Granum, P., Hangst, J. S., Hayden, M. E., Hodgkinson, D., Hunter, E. D., Isaac, C. A., Jimenez, A. J. U., Johnson, M. A., Jones, J. M., Jones, S. A., Jonsell, S., Khramov, A., Madsen, N., Martin, L., Massacret, N., Maxwell, D., McKenna, J. T. K., Menary, S., Momose, T., Mostamand, M., Mullan, P. S., Nauta, J., Olchanski, K., Oliveira, A. N., Peszka, J., Powell, A., Rasmussen, C. Ø., Robicheaux, F., Sacramento, R. L., Sameed, M., Sarid, E., Schoonwater, J., Silveira, D. M., Singh, J., Smith, G., So, C., Stracka, S., Stutter, G., Tharp, T. D., Thompson, K. A., Thompson, R. I., Thorpe-Woods, E., Torkzaban, C., Urioni, M., Woosaree, P., and Wurtele, J. S.

Published
2023
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4. Limit on the Electric Charge of Antihydrogen

Author

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.

Subjects
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

Published
2021
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5. Laser cooling of antihydrogen atoms

Author

Baker, C. J., Bertsche, W., Capra, A., Carruth, C., Cesar, C. L., Charlton, M., Christensen, A., Collister, R., Mathad, A. Cridland, Eriksson, S., Evans, A., Evetts, N., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Grandemange, P., Granum, P., Hangst, J. S., Hardy, W. N., Hayden, M. E., Hodgkinson, D., Hunter, E., Isaac, C. A., Johnson, M. A., Jones, J. M., Jones, S. A., Jonsell, S., Khramov, A., Knapp, P., Kurchaninov, L., Madsen, N., Maxwell, D., McKenna, J. T. K., Menary, S., Michan, J. M., Momose, T., Mullan, P. S., Munich, J. J., Olchanski, K., Olin, A., Peszka, J., Powell, A., Pusa, P., Rasmussen, C. Ø., Robicheaux, F., Sacramento, R. L., Sameed, M., Sarid, E., Silveira, D. M., Starko, D. M., So, C., Stutter, G., Tharp, T. D., Thibeault, A., Thompson, R. I., van der Werf, D. P., and Wurtele, J. S.

Published
2021
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6. In situ electromagnetic field diagnostics with an electron plasma in a Penning-Malmberg trap

Author

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
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7. Sympathetic cooling of positrons to cryogenic temperatures for antihydrogen production

Author

Baker, C. J., Bertsche, W., Capra, A., Cesar, C. L., Charlton, M., Mathad, A. Cridland, Eriksson, S., Evans, A., Evetts, N., Fabbri, S., Fajans, J., Friesen, T., Fujiwara, M. C., Grandemange, P., Granum, P., Hangst, J. S., Hayden, M. E., Hodgkinson, D., Isaac, C. A., Johnson, M. A., Jones, J. M., Jones, S. A., Jonsell, S., Kurchaninov, L., Madsen, N., Maxwell, D., McKenna, J. T. K., Menary, S., Momose, T., Mullan, P., Olchanski, K., Olin, A., Peszka, J., Powell, A., Pusa, P., Rasmussen, C. Ø., Robicheaux, F., Sacramento, R. L., Sameed, M., Sarid, E., Silveira, D. M., Stutter, G., So, C., Tharp, T. D., Thompson, R. I., van der Werf, D. P., and Wurtele, J. S.

Published
2021
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8. Antihydrogen and mirror-trapped antiproton discrimination: Discriminating between antihydrogen and mirror-trapped antiprotons in a minimum-B trap

Author

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
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9. Confinement of antihydrogen for 1000 seconds

Author

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
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10. Centrifugal separation and equilibration dynamics in an electron-antiproton plasma

Author

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
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11. Alpha Antihydrogen Experiment

Author

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

12. Evaporative Cooling of Antiprotons to Cryogenic Temperatures

Author

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
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13. Antihydrogen formation dynamics in a multipolar neutral anti-atom trap

Author

Andresen, G. B., Bertsche, W., Bowe, P. D., Bray, C., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Fajans, J., Fujiwara, M. C., Gill, D. R., Hangst, J. S., Hardy, W. N., Hayano, R. S., Hayden, M. E., Humphries, A. J., Hydomako, R., Jørgensen, L. V., Kerrigan, S. J., Kurchaninov, L., Lambo, R., Madsen, N., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Nasr, S. Seif El, Silveira, D. M., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., and Yamazaki, Y.

Subjects
High Energy Physics - Experiment, Physics - Atomic Physics, Physics - Plasma Physics
Abstract

Antihydrogen production in a neutral atom trap formed by an octupole-based magnetic field minimum is demonstrated using field-ionization of weakly bound anti-atoms. Using our unique annihilation imaging detector, we correlate antihydrogen detection by imaging and by field-ionization for the first time. We further establish how field-ionization causes radial redistribution of the antiprotons during antihydrogen formation and use this effect for the first simultaneous measurements of strongly and weakly bound antihydrogen atoms. Distinguishing between these provides critical information needed in the process of optimizing for trappable antihydrogen. These observations are of crucial importance to the ultimate goal of performing CPT tests involving antihydrogen, which likely depends upon trapping the anti-atom.

Published
2010
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14. Production of antihydrogen at reduced magnetic field for anti-atom trapping

Author

Andresen, G B, Bertsche, W, Boston, A, Bowe, P D, Cesar, C L, Chapman, S, Charlton, M, Chartier, M, Deutsch, A, Fajans, J, Fujiwara, M C, Funakoshi, R, Gill, D R, Gomberoff, K, Hangst, J S, Hayano, R S, Hydomako, R, Jenkins, M J, Jorgensen, L V, Kurchaninov, L, Madsen, N, Nolan, P, Olchanski, K, Olin, A, Page, R D, Povilus, A, Robicheaux, F, Sarid, E, Silveira, D M, Storey, J W, Thompson, R I, van derWerf, D P, Wurtele, J S, and Yamazaki, Y

Subjects
Nuclear Experiment
Abstract

We have demonstrated production of antihydrogen in a 1$,$T solenoidal magnetic field. This field strength is significantly smaller than that used in the first generation experiments ATHENA (3$,$T) and ATRAP (5$,$T). The motivation for using a smaller magnetic field is to facilitate trapping of antihydrogen atoms in a neutral atom trap surrounding the production region. We report the results of measurements with the ALPHA (Antihydrogen Laser PHysics Apparatus) device, which can capture and cool antiprotons at 3$,$T, and then mix the antiprotons with positrons at 1$,$T. We infer antihydrogen production from the time structure of antiproton annihilations during mixing, using mixing with heated positrons as the null experiment, as demonstrated in ATHENA. Implications for antihydrogen trapping are discussed.

Published
2008
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15. A novel antiproton radial diagnostic based on octupole induced ballistic loss

Author

Andresen, G. B., Bertsche, W., Bowe, P. D., Bray, C. C., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Fajans, J., Fujiwara, M. C., Funakoshi, R., Gill, D. R., Hangst, J. S., Hardy, W. N., Hayano, R. S., Hayden, M. E., Humphries, A. J., Hydomako, R., Jenkins, M. J., Jorgensen, L. V., Kurchaninov, L., Lambo, R., Madsen, N., Nolan, P., Olchanski, K., Olin, A., Page, R. D., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Nasr, S. Seif El, Silveira, D. M., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., and Yamazaki, Y.

Subjects
Physics - Atomic Physics, Nuclear Experiment
Abstract

We report results from a novel diagnostic that probes the outer radial profile of trapped antiproton clouds. The diagnostic allows us to determine the profile by monitoring the time-history of antiproton losses that occur as an octupole field in the antiproton confinement region is increased. We show several examples of how this diagnostic helps us to understand the radial dynamics of antiprotons in normal and nested Penning-Malmberg traps. Better understanding of these dynamics may aid current attempts to trap antihydrogen atoms.

Published
2008
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16. Compression of Antiproton Clouds for Antihydrogen Trapping

Author

Andresen, G. B., Bertsche, W., Bowe, P. D., Bray, C. C., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Fajans, J., Fujiwara, M. C., Funakoshi, R., Gill, D. R., Hangst, J. S., Hardy, W. N., Hayano, R. S., Hayden, M. E., Hydomako, R., Jenkins, M. J., Jorgensen, L. V., Kurchaninov, L., Lambo, R., Madsen, N., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Nasr, S. Seif El, Silveira, D. M., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., and Yamazaki, Y.

Subjects
Nuclear Experiment
Abstract

Control of the radial profile of trapped antiproton clouds is critical to trapping antihydrogen. We report the first detailed measurements of the radial manipulation of antiproton clouds, including areal density compressions by factors as large as ten, by manipulating spatially overlapped electron plasmas. We show detailed measurements of the near-axis antiproton radial profile and its relation to that of the electron plasma.

Published
2008
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17. Particle Physics Aspects of Antihydrogen Studies with ALPHA at CERN

Author

ALPHA Collaboration, Fujiwara, M. C., Andresen, G. B., Bertsche, W., Bowe, P. D., Bray, C. C., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Fajans, J., Funakoshi, R., Gill, D. R., Hangst, J. S., Hardy, W. N., Hayano, R. S., Hayden, M. E., Humphries, A. J., Hydomako, R., Jenkins, M. J., Jorgensen, L. V., Kurchaninov, L., Lai, W., Lambo, R., Madsen, N., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Nasr, S. Seif El, Silveira, D. M., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wasilenko, L., Wurtele, J. S., and Yamazaki, Y.

Subjects
High Energy Physics - Experiment, High Energy Physics - Phenomenology, Nuclear Experiment, Physics - Atomic Physics
Abstract

We discuss aspects of antihydrogen studies, that relate to particle physics ideas and techniques, within the context of the ALPHA experiment at CERN's Antiproton Decelerator facility. We review the fundamental physics motivations for antihydrogen studies, and their potential physics reach. We argue that initial spectroscopy measurements, once antihydrogen is trapped, could provide competitive tests of CPT, possibly probing physics at the Planck Scale. We discuss some of the particle detection techniques used in ALPHA. Preliminary results from commissioning studies of a partial system of the ALPHA Si vertex detector are presented, the results of which highlight the power of annihilation vertex detection capability in antihydrogen studies., Comment: Invited talk at Pbar08 - Workshop on Cold Antimatter Plasmas and Application to Fundamental Physics, Okinawa, Japan, 2008. 14 pages, 8 figures

Published
2008
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18. Towards Antihydrogen Confinement with the ALPHA Antihydrogen Trap

Author

Fujiwara, M. C., Andresen, G., Bertsche, W., Boston, A., Bowe, P. D., Cesar, C. L., Chapman, S., Charlton, M., Chartier, M., Deutsch, A., Fajans, J., Funakoshi, R., Gill, D. R., Gomberoff, K., Hangst, J. S., Hardy, W. N., Hayano, R. S., Hydomako, R., Jenkins, M. J., Jorgensen, L. V., Kurchaninov, L., Madsen, N., Nolan, P., Olchanski, K., Olin, A., Page, R. D., Povilus, A., Robicheaux, F., Sarid, E., Silveira, D. M., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., and Yamazaki, Y.

Subjects
Nuclear Experiment, High Energy Physics - Experiment, Physics - Atomic Physics, Physics - Plasma Physics
Abstract

ALPHA is an international project that has recently begun experimentation at CERN's Antiproton Decelerator (AD) facility. The primary goal of ALPHA is stable trapping of cold antihydrogen atoms with the ultimate goal of precise spectroscopic comparisons with hydrogen. We discuss the status of the ALPHA project and the prospects for antihydrogen trapping., Comment: Invited talk at International Conference on Trapped Charged Particles and Fundamental Physics: TCP06, Parksville, BC, Canada, September 2006. To be published in Hyperfine Interactions

Published
2007
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19. Antiproton cloud compression in the ALPHA apparatus at CERN

Author

Gutierrez, A., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Burrows, C., Butler, E., Capra, A., Cesar, C. L., Charlton, M., Dunlop, R., Eriksson, S., Evetts, N., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., 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., Olchanski, K., Olin, A., Pusa, P., Rasmussen, C. Ø., Robicheaux, F., Sacramento, R. L., Sarid, E., Silveira, D. M., So, C., Stracka, S., Tarlton, J., Tharp, T. D., Thompson, R. I., Tooley, P., Turner, M., van der Werf, D. P., Wurtele, J. S., Zhmoginov, A. I., Wada, Michiharu, editor, Schury, Peter, editor, and Ichikawa, Yuichi, editor

Published
2017
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20. Description and first application of a new technique to measure the gravitational mass of antihydrogen

Author

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

21. Observation of the 1S–2P Lyman-α transition in antihydrogen

Author

Ahmadi, M., Alves, B. X. R., Baker, C. J., Bertsche, W., 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., Hangst, J. S., Hardy, W. N., Hayden, M. E., Hunter, E. D., Isaac, C. A., Johnson, M. A., Jones, J. M., Jones, S. A., Jonsell, S., Khramov, A., Knapp, P., Kurchaninov, L., Madsen, N., Maxwell, D., McKenna, J. T. K., Menary, S., Michan, J. M., Momose, T., Munich, J. J., Olchanski, K., Olin, A., Pusa, P., Rasmussen, C. Ø., Robicheaux, F., Sacramento, R. L., Sameed, M., Sarid, E., Silveira, D. M., Starko, D. M., Stutter, G., So, C., Tharp, T. D., Thompson, R. I., van der Werf, D. P., and Wurtele, J. S.

Published
2018
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22. Characterization of the 1S–2S transition in antihydrogen

Author

Ahmadi, M., Alves, B. X. R., Baker, C. J., Bertsche, W., 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., Hangst, J. S., Hardy, W. N., Hayden, M. E., Isaac, C. A., Johnson, M. A., Jones, J. M., Jones, S. A., Jonsell, S., Khramov, A., Knapp, P., Kurchaninov, L., Madsen, N., Maxwell, D., McKenna, J. T. K., Menary, S., Momose, T., Munich, J. J., Olchanski, K., Olin, A., Pusa, P., Rasmussen, C. Ø., Robicheaux, F., Sacramento, R. L., Sameed, M., Sarid, E., Silveira, D. M., Stutter, G., So, C., Tharp, T. D., Thompson, R. I., van der Werf, D. P., and Wurtele, J. S.

Published
2018
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23. 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
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24. 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
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25. Limit on the electric charge of antihydrogen

Author

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., K. McKenna, J. T., 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.

Published
2017
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26. Observation of the 1S–2S 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. 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
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27. Antiproton cloud compression in the ALPHA apparatus at CERN

Author

Gutierrez, A., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Burrows, C., Butler, E., Capra, A., Cesar, C. L., Charlton, M., Dunlop, R., Eriksson, S., Evetts, N., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Hangst, J. S., Hardy, W. N., Hayden, M. E., Isaac, C. A., Jonsell, S., Kurchaninov, L., Little, A., Madsen, N., K. McKenna, J. T., Menary, S., Napoli, S. C., Nolan, P., Olchanski, K., Olin, A., Pusa, P., Rasmussen, C. Ø., Robicheaux, F., Sacramento, R. L., Sarid, E., Silveira, D. M., So, C., Stracka, S., Tarlton, J., Tharp, T. D., Thompson, R. I., Tooley, P., Turner, M., van der Werf, D. P., Wurtele, J. S., and Zhmoginov, A. I.

Published
2015
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28. An improved limit on the charge of antihydrogen from stochastic acceleration

Author

Ahmadi, M., Baquero-Ruiz, M., Bertsche, W., Butler, E., Capra, A., Carruth, C., Cesar, C. L., Charlton, M., Charman, A. E., Eriksson, S., Evans, L. T., 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., Jones, S. A., Jonsell, S., Kurchaninov, L., Madsen, N., Maxwell, D., McKenna, J. T. K., Menary, S., Michan, J. M., Momose, T., Munich, J. J., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Rasmussen, C. Ø., Robicheaux, F., Sacramento, R. L., Sameed, M., Sarid, E., Silveira, D. M., So, C., Tharp, T. D., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., and Zhmoginov, A. I.

Published
2016
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29. Antiproton cloud compression in the ALPHA apparatus at CERN

Author

Gutierrez, A., primary, Ashkezari, M. D., additional, Baquero-Ruiz, M., additional, Bertsche, W., additional, Burrows, C., additional, Butler, E., additional, Capra, A., additional, Cesar, C. L., additional, Charlton, M., additional, Dunlop, R., additional, Eriksson, S., additional, Evetts, N., additional, Fajans, J., additional, Friesen, T., additional, Fujiwara, M. C., additional, Gill, D. R., additional, Hangst, J. S., additional, Hardy, W. N., additional, Hayden, M. E., additional, Isaac, C. A., additional, Jonsell, S., additional, Kurchaninov, L., additional, Little, A., additional, Madsen, N., additional, McKenna, J. T. K., additional, Menary, S., additional, Napoli, S. C., additional, Nolan, P., additional, Olchanski, K., additional, Olin, A., additional, Pusa, P., additional, Rasmussen, C. Ø., additional, Robicheaux, F., additional, Sacramento, R. L., additional, Sarid, E., additional, Silveira, D. M., additional, So, C., additional, Stracka, S., additional, Tarlton, J., additional, Tharp, T. D., additional, Thompson, R. I., additional, Tooley, P., additional, Turner, M., additional, van der Werf, D. P., additional, Wurtele, J. S., additional, and Zhmoginov, A. I., additional

Published
2015
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30. Erratum: 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
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
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31. Microwave-plasma interactions studied via mode diagnostics in ALPHA

Author

Friesen, T., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Eriksson, S., Fajans, J., 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., Kurchaninov, L., 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., Wurtele, J. S., Yamazaki, Y., and ALPHA Collaboration

Published
2012
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32. Trapped antihydrogen

Author

Butler, E., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., 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., Kemp, S. L., Kurchaninov, L., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Rasmussen, C. Ø., Robicheaux, F., Sarid, E., Seif el Nasr, S., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., Yamazaki, Y., and ALPHA Collaboration

Published
2012
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33. Alternative method for reconstruction of antihydrogen annihilation vertices

Author

Amole, C., Ashkezari, M. D., Andresen, G. B., 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., Hayano, R. S., Hayden, M. E., Humphries, A. J., Hydomako, R., Jonsell, S., Kurchaninov, L., 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., Wurtele, J. S., Yamazaki, Y., and ALPHA Collaboration

Published
2012
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34. Antihydrogen formation by autoresonant excitation of antiproton plasmas

Author

Bertsche, William Alan, Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bowe, P. D., Carpenter, P. T., Butler, E., Cesar, C. L., Chapman, S. F., Charlton, M., 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., Hurt, J. L., Hydomako, R., Jonsell, S., Kurchaninov, L., 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., Werf, D. P. van der, Wurtele, J. S., Yamazaki, Y., and ALPHA Collaboration

Published
2012
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35. Towards antihydrogen trapping and spectroscopy at ALPHA

Author

Butler, E., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Bray, C. C., 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. 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., Yamazaki, Y., and ALPHA Collaboration

Published
2011
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36. Towards antihydrogen confinement with the ALPHA antihydrogen trap

Author

Fujiwara, M. C., Andresen, G., Bertsche, W., Boston, A., Bowe, P. D., Cesar, C. L., Chapman, S., Charlton, M., Chartier, M., Deutsch, A., Fajans, J., Funakoshi, R., Gill, D. R., Gomberoff, K., Hangst, J. S., Hardy, W. N., Hayano, R. S., Hydomako, R., Jenkins, M. J., Jørgensen, L. V., Kurchaninov, L., Madsen, N., Nolan, P., Olchanski, K., Olin, A., Page, R. D., Povilus, A., Robicheaux, F., Sarid, E., Silveira, D. M., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., and Yamazaki, Y.

Published
2006
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37. Investigation of the fine structure of antihydrogen

Author

Ahmadi, M., Alves, B. X. R., Baker, C. J., Bertsche, W., 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., Granum, P., Hangst, J. S., Hardy, W. N., Hayden, M. E., Hunter, E. D., Isaac, C. A., Johnson, M. A., Jones, J. M., Jones, S. A., Jonsell, Svante, Khramov, A., Knapp, P., Kurchaninov, L., Madsen, N., Maxwell, D., McKenna, J. T. K., Menary, S., Michan, J. M., Momose, T., Munich, J. J., Olchanski, K., Olin, A., Pusa, P., Rasmussen, C. Ø., Robicheaux, F., Sacramento, R. L., Sameed, M., Sarid, E., Silveira, D. M., So, C., Starko, D. M., Stutter, G., Tharp, T. D., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., Ahmadi, M., Alves, B. X. R., Baker, C. J., Bertsche, W., 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., Granum, P., Hangst, J. S., Hardy, W. N., Hayden, M. E., Hunter, E. D., Isaac, C. A., Johnson, M. A., Jones, J. M., Jones, S. A., Jonsell, Svante, Khramov, A., Knapp, P., Kurchaninov, L., Madsen, N., Maxwell, D., McKenna, J. T. K., Menary, S., Michan, J. M., Momose, T., Munich, J. J., Olchanski, K., Olin, A., Pusa, P., Rasmussen, C. Ø., Robicheaux, F., Sacramento, R. L., Sameed, M., Sarid, E., Silveira, D. M., So, C., Starko, D. M., Stutter, G., Tharp, T. D., Thompson, R. I., van der Werf, D. P., and Wurtele, J. S.

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 2S(1/2) and 2P(1/2) states(1). 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 electrodynamics(2-5). 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-alpha transitions in antihydrogen(6), 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 (2P(1/2)-2P(3/2)) 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 frequency(6,7), we find that the classic Lamb shift in antihydrogen (2S(1/2)-2P(1/2) 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 symmetry(8) and towards the determination of other fundamental quantities, such as the antiproton charge radius(9,10), in this antimatter system. Precision measurements of the 1S-2P transition in an

Published
2020
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39. Towards antihydrogen confinement with the ALPHA antihydrogen trap

Author

Fujiwara, M. C., primary, Gill, D. R., additional, Kurchaninov, L., additional, Olchanski, K., additional, Olin, A., additional, Storey, J. W., additional, Andresen, G., additional, Bowe, P. D., additional, Hangst, J. S., additional, Bertsche, W., additional, Chapman, S., additional, Deutsch, A., additional, Fajans, J., additional, Povilus, A., additional, Wurtele, J. S., additional, Boston, A., additional, Chartier, M., additional, Nolan, P., additional, Page, R. D., additional, Cesar, C. L., additional, Silveira, D. M., additional, Charlton, M., additional, Jenkins, M. J., additional, Jørgensen, L. V., additional, Madsen, N., additional, van der Werf, D. P., additional, Funakoshi, R., additional, Hayano, R. S., additional, Gomberoff, K., additional, Hardy, W. N., additional, Hydomako, R., additional, Thompson, R. I., additional, Robicheaux, F., additional, Sarid, E., additional, and Yamazaki, Y., additional

Published
2007
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40. Trapped antihydrogen

Author

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
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41. Observation of the 1S-2P Lyman-alpha transition in antihydrogen

Author

Ahmadi, M., Alves, B. X. R., Baker, C. J., Bertsche, W., 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., Hangst, J. S., Hardy, W. N., Hayden, M. E., Hunter, E. D., Isaac, C. A., Johnson, M. A., Jones, J. M., Jones, S. A., Jonsell, Svante, Khramov, A., Knapp, P., Kurchaninov, L., Madsen, N., Maxwell, D., McKenna, J. T. K., Menary, S., Michan, J. M., Momose, T., Munich, J. J., Olchanski, K., Olin, A., Pusa, P., Rasmussen, C. O., Robicheaux, F., Sacramento, R. L., Sameed, M., Sarid, E., Silveira, D. M., Starko, D. M., Stutter, G., So, C., Tharp, T. D., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., Ahmadi, M., Alves, B. X. R., Baker, C. J., Bertsche, W., 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., Hangst, J. S., Hardy, W. N., Hayden, M. E., Hunter, E. D., Isaac, C. A., Johnson, M. A., Jones, J. M., Jones, S. A., Jonsell, Svante, Khramov, A., Knapp, P., Kurchaninov, L., Madsen, N., Maxwell, D., McKenna, J. T. K., Menary, S., Michan, J. M., Momose, T., Munich, J. J., Olchanski, K., Olin, A., Pusa, P., Rasmussen, C. O., Robicheaux, F., Sacramento, R. L., Sameed, M., Sarid, E., Silveira, D. M., Starko, D. M., Stutter, G., So, C., Tharp, T. D., Thompson, R. I., van der Werf, D. P., and Wurtele, J. S.

Abstract

In 1906, Theodore Lyman discovered his eponymous series of transitions in the extreme-ultraviolet region of the atomic hydrogen spectrum(1,2). 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-alpha 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-alpha forest('3) of absorption lines at different redshifts. Here we report the observation of the Lyman-alpha 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 (1 sigma uncertainty) and agrees with the prediction for hydrogen to a precision of 5 x 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 hyperfine(4,5) and 1S-2S transitions(6,7) recently observed in antihydrogen, the Lyman-alpha transition will permit laser cooling of antihydrogen(8,9), thus providing a cold and dense sample of anti-atoms for precision spectroscopy and gravity measurements(10). 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
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42. Enhanced Control and Reproducibility of Non-Neutral Plasmas

Author

Ahmadi, M., Alves, B. X. R., Baker, C. J., Bertsche, W., 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., Hangst, J. S., Hardy, W. N., Hayden, M. E., Isaac, C. A., Johnson, M. A., Jones, S. A., Jonsell, Svante, Kurchaninov, L., Madsen, N., Mathers, M., Maxwell, D., McKenna, J. T. K., Menary, S., Momose, T., Munich, J. J., Olchanski, K., Olin, A., Pusa, P., Rasmussen, C. O., Robicheaux, F., Sacramento, R. L., Sameed, M., Sarid, E., Silveira, D. M., So, C., Stutter, G., Tharp, T. D., Thompson, J. E., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., Ahmadi, M., Alves, B. X. R., Baker, C. J., Bertsche, W., 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., Hangst, J. S., Hardy, W. N., Hayden, M. E., Isaac, C. A., Johnson, M. A., Jones, S. A., Jonsell, Svante, Kurchaninov, L., Madsen, N., Mathers, M., Maxwell, D., McKenna, J. T. K., Menary, S., Momose, T., Munich, J. J., Olchanski, K., Olin, A., Pusa, P., Rasmussen, C. O., Robicheaux, F., Sacramento, R. L., Sameed, M., Sarid, E., Silveira, D. M., So, C., Stutter, G., Tharp, T. D., Thompson, J. E., Thompson, R. I., van der Werf, D. P., and Wurtele, J. S.

Abstract

The simultaneous control of the density and particle number of non-neutral plasmas confined in Penning-Malmberg traps is demonstrated. Control is achieved by setting the plasma's density by applying a rotating electric field while simultaneously fixing its axial potential via evaporative cooling. This novel method is particularly useful for stabilizing positron plasmas, as the procedures used to collect positrons from radioactive sources typically yield plasmas with variable densities and particle numbers; it also simplifies optimization studies that require plasma parameter scans. The reproducibility achieved by applying this technique to the positron and electron plasmas used by the ALPHA antihydrogen experiment at CERN, combined with other developments, contributed to a 10-fold increase in the antiatom trapping rate.

Published
2018
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43. Erratum: Observation of the hyperfine spectrum of antihydrogen

Author

Ahmadi, M., primary, Alves, B. X. R., additional, Baker, C. J., additional, Bertsche, W., additional, Butler, E., additional, Capra, A., additional, Carruth, C., additional, Cesar, C. L., additional, Charlton, M., additional, Cohen, S., additional, Collister, R., additional, Eriksson, S., additional, Evans, A., additional, Evetts, N., additional, Fajans, J., additional, Friesen, T., additional, Fujiwara, M. C., additional, Gill, D. R., additional, Gutierrez, A., additional, Hangst, J. S., additional, Hardy, W. N., additional, Hayden, M. E., additional, Isaac, C. A., additional, Ishida, A., additional, Johnson, M. A., additional, Jones, S. A., additional, Jonsell, S., additional, Kurchaninov, L., additional, Madsen, N., additional, Mathers, M., additional, Maxwell, D., additional, McKenna, J. T. K., additional, Menary, S., additional, Michan, J. M., additional, Momose, T., additional, Munich, J. J., additional, Nolan, P., additional, Olchanski, K., additional, Olin, A., additional, Pusa, P., additional, Rasmussen, C. Ø., additional, Robicheaux, F., additional, Sacramento, R. L., additional, Sameed, M., additional, Sarid, E., additional, Silveira, D. M., additional, Stracka, S., additional, Stutter, G., additional, So, C., additional, Tharp, T. D., additional, Thompson, J. E., additional, Thompson, R. I., additional, van der Werf, D. P., additional, and Wurtele, J. S., additional

Published
2017
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44. Antihydrogen accumulation for fundamental symmetry tests

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, Svante, 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., Wurtele, J. S., 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, Svante, 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.

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.

Published
2017
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45. Antihydrogen accumulation for fundamental symmetry tests

Author

Ahmadi, M., primary, Alves, B. X. R., additional, Baker, C. J., additional, Bertsche, W., additional, Butler, E., additional, Capra, A., additional, Carruth, C., additional, Cesar, C. L., additional, Charlton, M., additional, Cohen, S., additional, Collister, R., additional, Eriksson, S., additional, Evans, A., additional, Evetts, N., additional, Fajans, J., additional, Friesen, T., additional, Fujiwara, M. C., additional, Gill, D. R., additional, Gutierrez, A., additional, Hangst, J. S., additional, Hardy, W. N., additional, Hayden, M. E., additional, Isaac, C. A., additional, Ishida, A., additional, Johnson, M. A., additional, Jones, S. A., additional, Jonsell, S., additional, Kurchaninov, L., additional, Madsen, N., additional, Mathers, M., additional, Maxwell, D., additional, McKenna, J. T. K., additional, Menary, S., additional, Michan, J. M., additional, Momose, T., additional, Munich, J. J., additional, Nolan, P., additional, Olchanski, K., additional, Olin, A., additional, Pusa, P., additional, Rasmussen, C. Ø., additional, Robicheaux, F., additional, Sacramento, R. L., additional, Sameed, M., additional, Sarid, E., additional, Silveira, D. M., additional, Stracka, S., additional, Stutter, G., additional, So, C., additional, Tharp, T. D., additional, Thompson, J. E., additional, Thompson, R. I., additional, van der Werf, D. P., additional, and Wurtele, J. S., additional

Published
2017
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46. Limit on the electric charge of antihydrogen

Author

Capra, A., primary, Amole, C., additional, Ashkezari, M. D., additional, Baquero-Ruiz, M., additional, Bertsche, W., additional, Butler, E., additional, Cesar, C. L., additional, Charlton, M., additional, Eriksson, S., additional, Fajans, J., additional, Friesen, T., additional, Fujiwara, M. C., additional, Gill, D. R., additional, Gutierrez, A., additional, Hangst, J. S., additional, Hardy, W. N., additional, Hayden, M. E., additional, Isaac, C. A., additional, Jonsell, S., additional, Kurchaninov, L., additional, Little, A., additional, K. McKenna, J. T., additional, Menary, S., additional, Napoli, S. C., additional, Nolan, P., additional, Olchanski, K., additional, Olin, A., additional, Povilus, A., additional, Pusa, P., additional, Robicheaux, F., additional, Sarid, E., additional, Silveira, D. M., additional, So, C., additional, Tharp, T. D., additional, Thompson, R. I., additional, van der Werf, D. P., additional, Vendeiro, Z., additional, Wurtele, J. S., additional, Zhmoginov, A. I., additional, and Charman, A. E., additional

Published
2016
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47. Observation of the 1S–2S transition in trapped antihydrogen

Author

Ahmadi, M., primary, Alves, B. X. R., additional, Baker, C. J., additional, Bertsche, W., additional, Butler, E., additional, Capra, A., additional, Carruth, C., additional, Cesar, C. L., additional, Charlton, M., additional, Cohen, S., additional, Collister, R., additional, Eriksson, S., additional, Evans, A., additional, Evetts, N., additional, Fajans, J., additional, Friesen, T., additional, Fujiwara, M. C., additional, Gill, D. R., additional, Gutierrez, A., additional, Hangst, J. S., additional, Hardy, W. N., additional, Hayden, M. E., additional, Isaac, C. A., additional, Ishida, A., additional, Johnson, M. A., additional, Jones, S. A., additional, Jonsell, S., additional, Kurchaninov, L., additional, Madsen, N., additional, Mathers, M., additional, Maxwell, D., additional, McKenna, J. T. K., additional, Menary, S., additional, Michan, J. M., additional, Momose, T., additional, Munich, J. J., additional, Nolan, P., additional, Olchanski, K., additional, Olin, A., additional, Pusa, P., additional, Rasmussen, C. Ø., additional, Robicheaux, F., additional, Sacramento, R. L., additional, Sameed, M., additional, Sarid, E., additional, Silveira, D. M., additional, Stracka, S., additional, Stutter, G., additional, So, C., additional, Tharp, T. D., additional, Thompson, J. E., additional, Thompson, R. I., additional, van der Werf, D. P., additional, and Wurtele, J. S., additional

Published
2016
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48. Towards antihydrogen trapping and spectroscopy at ALPHA:Proceedings of the 5th International Conference on Trapped Charged Particles and Fundamental Physics (TCP 2010

Author

Butler, E., Bruun Andresen, Gorm, Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, Paul David, Bray, C. C., Cesar, C. L., Chapman, S., Charlton, M., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Hangst, Jeffrey 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., Seif el Nasr, S., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wilding, D., Wurtele, J. S., and Yamazaki, Y.

Published
2011

49. ALPHA ANTIHYDROGEN EXPERIMENT

Author

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
Condensed Matter::Quantum Gases, Physics, Physics::General Physics, Atomic Physics (physics.atom-ph), FOS: Physical sciences, Alpha (ethology), Physics - Plasma Physics, High Energy Physics - Experiment, Physics - Atomic Physics, 3. Good health, Plasma Physics (physics.plasm-ph), Nuclear physics, High Energy Physics - Phenomenology, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), Physics::Atomic and Molecular Clusters, Nuclear Physics - Experiment, Physics::Atomic Physics, Nuclear Experiment (nucl-ex), Antihydrogen, Nuclear Experiment
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
2010

50. An experimental limit on the charge of antihydrogen

Author

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, Svante, Kurchaninov, L., Little, A., Madsen, N., McKenna, J. T. K., Menary, S., Napoli, S. C., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Rasmussen, C. O., 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., Charman, A. E., 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, Svante, Kurchaninov, L., Little, A., Madsen, N., McKenna, J. T. K., Menary, S., Napoli, S. C., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Rasmussen, C. O., 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.

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 +/- 3.4mm for an average axial electric field of 0.51Vmm1. 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., AuthorCount:42

Published
2014
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