Search

Your search keyword '"Ashkezari, M. D."' showing total 102 results
Start Over Author "Ashkezari, M. D."
102 results on '"Ashkezari, M. D."'

1. 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
Full Text
View/download PDF

2. 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
Full Text
View/download PDF

3. 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
Full Text
View/download PDF

4. 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
Full Text
View/download PDF

5. 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
Full Text
View/download PDF

6. 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

7. 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
Full Text
View/download PDF

8. 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
Full Text
View/download PDF

9. 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

10. 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
Full Text
View/download PDF

11. 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
Full Text
View/download PDF

12. 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
Full Text
View/download PDF

13. 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
Full Text
View/download PDF

14. 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
Full Text
View/download PDF

15. 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
Full Text
View/download PDF

16. 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
Full Text
View/download PDF

17. 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
Full Text
View/download PDF

18. 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
Full Text
View/download PDF

19. Microwave Spectroscopy of Magnetically Trapped Atomic Antihydrogen

Author

Ashkezari, M D

Subjects
Physics in General
Abstract

We have every reason to believe that equal amounts of matter and antimatter were produced in the early universe. Moreover, theory predicts that the laws of physics make no distinc- tion between the two. In this light, the fact that the observable universe is overwhelmingly dominated by matter is inexplicable. ALPHA is an international project located at CERN involving approximately 40 physi- cists from 15 different institutions in 7 countries. The primary goal of the collaboration is to study the antihydrogen atom at the highest level of precision possible, and thereby enable comparisons between hydrogen and antihydrogen. Through these comparisons it hopes to improve our understanding of the distinction between matter and antimatter, and perhaps shed some light on the puzzle of why we live in a matter dominated universe. The hyperfine energy intervals of ground-state hydrogen and antihydrogen represent an opportunity for a precision comparison. A discrepancy between the energy levels of these two atomic sys- tems would indicate a major revolution in physics, and in our understanding of the universe. This thesis describes and interprets the first proof-of-principle spectroscopic measure- ments performed on magnetically trapped antihydrogen atoms. The experiments were per- formed by the ALPHA collaboration using microwave radiation tuned to induce transitions between hyperfine levels of ground state antihydrogen atoms. Our observations confirm that positron spin resonance transitions between hyperfine levels of ground state antihydro- gen are consistent with expectations for hydrogen to within 4 parts in 103. The hyperfine splitting of ground state antihydrogen atoms is also constrained to 1420 ± 85 MHz.

Published
2017

20. 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
Full Text
View/download PDF

21. Antiparticle sources for antihydrogen production and trapping

Author

Charlton, M., Bruun Andresen, Gorm, Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, Paul David, Bray, C.C., Butler, E., Chapman, S., 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., Jørgensen, L.V., Kerrigan, S.J., Kurchaninov, L., Lambo, R., Madsen, N., Menary, S., Nolan, P., Olchanski, K., 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.

Subjects
Physics::General Physics, Physics::Atomic and Molecular Clusters, Physics::Accelerator Physics, High Energy Physics::Experiment, Physics::Atomic Physics
Abstract

Sources of positrons and antiprotons that are currently used for the formationof antihydrogen with low kinetic energies are reviewed, mostly in the context of the ALPHA collaboration and its predecessor ATHENA. The experiments were undertaken at the Antiproton Decelerator facility, which is located at CERN. Operations performed on the clouds of antiparticles to facilitate their mixing to produce antihydrogen are described. These include accumulation, cooling and manipulation. The formation of antihydrogen and some of the characteristics of the anti-atoms that are created are discussed. Prospects for trapping antihydrogen in a magnetic minimum trap, as envisaged by the ALPHA collaboration, are reviewed.

Published
2011
Full Text
View/download PDF

22. 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
Full Text
View/download PDF

23. 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
Full Text
View/download PDF

24. The ALPHA antihydrogen trapping apparatus

Author

Amole, C., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Capra, A., Carpenter, P. T., Cesar, C. L., Chapman, S., Charlton, M., Deller, A., Eriksson, S., Escallier, J., 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., Isaac, C. A., Jenkins, M. J., Jonsell, Svante, Jörgensen, L. V., Kerrigan, S. J., Kurchaninov, L., Madsen, N., Morone, A., McKenna, J. T. K., Menary, S., Nolan, P., Olchanski, K., Olin, A., Parker, B., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Seddon, D., El Nasr, S. Seif, Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., Thornhill, J., Wells, D., van der Werf, D. P., Wurtele, J. S., Yamazaki, Y., Amole, C., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Capra, A., Carpenter, P. T., Cesar, C. L., Chapman, S., Charlton, M., Deller, A., Eriksson, S., Escallier, J., 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., Isaac, C. A., Jenkins, M. J., Jonsell, Svante, Jörgensen, L. V., Kerrigan, S. J., Kurchaninov, L., Madsen, N., Morone, A., McKenna, J. T. K., Menary, S., Nolan, P., Olchanski, K., Olin, A., Parker, B., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Seddon, D., El Nasr, S. Seif, Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., Thornhill, J., Wells, D., van der Werf, D. P., Wurtele, J. S., and Yamazaki, Y.

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., AuthorCount:56

Published
2014
Full Text
View/download PDF

25. An experimental limit on the charge of antihydrogen

Author

Amole, C., primary, Ashkezari, M. D., additional, Baquero-Ruiz, M., additional, Bertsche, W., additional, Butler, E., additional, Capra, A., 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, Madsen, N., additional, McKenna, J. T. K., additional, Menary, S., additional, Napoli, S. C., additional, Nolan, P., additional, Olchanski, K., additional, Olin, A., additional, Povilus, A., additional, Pusa, P., additional, Rasmussen, C.Ø., 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
2014
Full Text
View/download PDF

26. In situ electromagnetic field diagnostics with an electron plasma in a Penning–Malmberg trap

Author

Amole, C, primary, Ashkezari, M D, additional, Baquero-Ruiz, M, additional, Bertsche, W, additional, Butler, E, additional, Capra, A, additional, Cesar, C L, additional, Charlton, M, additional, Deller, A, additional, Evetts, N, 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, Madsen, N, additional, McKenna, J T K, additional, Menary, S, additional, Napoli, S C, additional, Olchanski, K, additional, Olin, A, additional, Pusa, P, additional, Rasmussen, C Ø, additional, Robicheaux, F, additional, Sarid, E, additional, Silveira, D M, additional, So, C, additional, Stracka, S, additional, Tharp, T, additional, Thompson, R I, additional, van der Werf, D P, additional, and Wurtele, J S, additional

Published
2014
Full Text
View/download PDF

27. Experimental and computational study of the injection of antiprotons into a positron plasma for antihydrogen production

Author

Amole, C., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Butler, E., Capra, A., Cesar, C. L., 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., Isaac, C. A., Jonsell, Svante, Kurchaninov, L., Little, A., Madsen, N., McKenna, J. T. K., Menary, S., Napoli, S. C., Olchanski, K., Olin, A., Pusa, P., Rasmussen, C. O., Robicheaux, F., Sarid, E., Shields, C. R., Silveira, D. M., So, C., Stracka, S., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., Zhmoginov, A., Friedland, L., Amole, C., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Butler, E., Capra, A., Cesar, C. L., 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., Isaac, C. A., Jonsell, Svante, Kurchaninov, L., Little, A., Madsen, N., McKenna, J. T. K., Menary, S., Napoli, S. C., Olchanski, K., Olin, A., Pusa, P., Rasmussen, C. O., Robicheaux, F., Sarid, E., Shields, C. R., Silveira, D. M., So, C., Stracka, S., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., Zhmoginov, A., and Friedland, L.

Abstract

One of the goals of synthesizing and trapping antihydrogen is to study the validity of charge-parity-time symmetry through precision spectroscopy on the anti-atoms, but the trapping yield achieved in recent experiments must be significantly improved before this can be realized. Antihydrogen atoms are commonly produced by mixing antiprotons and positrons stored in a nested Penning-Malmberg trap, which was achieved in ALPHA by an autoresonant excitation of the antiprotons, injecting them into the positron plasma. In this work, a hybrid numerical model is developed to simulate antiproton and positron dynamics during the mixing process. The simulation is benchmarked against other numerical and analytic models, as well as experimental measurements. The autoresonant injection scheme and an alternative scheme are compared numerically over a range of plasma parameters which can be reached in current and upcoming antihydrogen experiments, and the latter scheme is seen to offer significant improvement in trapping yield as the number of available antiprotons increases., AuthorCount:41

Published
2013
Full Text
View/download PDF

28. Autoresonant-spectrometric determination of the residual gas composition in the ALPHA experiment apparatus

Author

Amole, C., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Butler, E., Capra, A., Cesar, C. L., Chapman, S., 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., Stracka, S., So, C., Thompson, R. I., Turner, M., van der Werf, D. P., Wurtele, J. S., Zhmoginov, A., Amole, C., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Butler, E., Capra, A., Cesar, C. L., Chapman, S., 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., Stracka, S., So, C., Thompson, R. I., Turner, M., van der Werf, D. P., Wurtele, J. S., and Zhmoginov, A.

Abstract

Knowledge of the residual gas composition in the ALPHA experiment apparatus is important in our studies of antihydrogen and nonneutral plasmas. A technique based on autoresonant ion extraction from an electrostatic potential well has been developed that enables the study of the vacuum in our trap. Computer simulations allow an interpretation of our measurements and provide the residual gas composition under operating conditions typical of those used in experiments to produce, trap, and study antihydrogen. The methods developed may also be applicable in a range of atomic and molecular trap experiments where Penning-Malmberg traps are used and where access is limited., AuthorCount:42

Published
2013
Full Text
View/download PDF

29. Silicon vertex detector upgrade in the ALPHA experiment

Author

Amole, C., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Burrows, C., Butler, E., Capra, A., 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., 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., Sacramento, R. L., Stracka, S., Sampson, J. A., Sarid, E., Seddon, D., Silveira, D. M., So, C., Thompson, R. I., Tharp, T., Thornhill, J., Tooley, M. P., van der Werf, D. P., Wells, D., Amole, C., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Burrows, C., Butler, E., Capra, A., 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., 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., Sacramento, R. L., Stracka, S., Sampson, J. A., Sarid, E., Seddon, D., Silveira, D. M., So, C., Thompson, R. I., Tharp, T., Thornhill, J., Tooley, M. P., van der Werf, D. P., and Wells, D.

Abstract

The Silicon Vertex Detector (SVD) is the main diagnostic tool in the ALPHA-experiment. It provides precise spatial and timing information of antiproton (antihydrogen) annihilation events (vertices), and most importantly, the SVD is capable of directly identifying and analysing single annihilation events, thereby forming the basis of ALPHA's analysis. This paper describes the ALPHA SVD and its upgrade, installed in the ALPHA's new neutral atom trap., AuthorCount:50

Published
2013
Full Text
View/download PDF

30. Antihydrogen annihilation reconstruction with the ALPHA silicon detector

Author

Andresen, G. B., Ashkezari, M. D., 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., Hayano, R. S., Humphries, A. J., Hydomako, R., Jonsell, Svante, Jorgensen, L. V., Kurchaninov, L., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Sarid, E., el Nasr, S. Seif, Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Yamazaki, Y., Andresen, G. B., Ashkezari, M. D., 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., Hayano, R. S., Humphries, A. J., Hydomako, R., Jonsell, Svante, Jorgensen, L. V., Kurchaninov, L., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Sarid, E., el Nasr, S. Seif, Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., and Yamazaki, Y.

Abstract

The ALPHA experiment has succeeded in trapping antihydrogen, a major milestone on the road to spectroscopic comparisons of antihydrogen with hydrogen. An annihilation vertex detector, which determines the time and position of antiproton annihilations, has been central to this achievement. This detector, an array of double-sided silicon microstrip detector modules arranged in three concentric cylindrical tiers, is sensitive to the passage of charged particles resulting from antiproton annihilation. This article describes the method used to reconstruct the annihilation location and to distinguish the annihilation signal from the cosmic ray background. Recent experimental results using this detector are outlined., AuthorCount:39

Published
2012
Full Text
View/download PDF

31. Resonant quantum transitions in trapped antihydrogen atoms

Author

Amole, C., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Capra, A., Cesar, C. L., Charlton, M., Deller, A., Donnan, P. H., 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., 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., Pusa, P., Rasmussen, C. O., Robicheaux, F., Sarid, E., Shields, C. R., Silveira, D. M., Stracka, S., So, C., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., Amole, C., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Capra, A., Cesar, C. L., Charlton, M., Deller, A., Donnan, P. H., 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., 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., Pusa, P., Rasmussen, C. O., Robicheaux, F., Sarid, E., Shields, C. R., Silveira, D. M., Stracka, S., So, C., Thompson, R. I., van der Werf, D. P., and Wurtele, J. S.

Abstract

The hydrogen atom is one of the most important and influential model systems in modern physics. Attempts to understand its spectrum are inextricably linked to the early history and development of quantum mechanics. The hydrogen atom's stature lies in its simplicity and in the accuracy with which its spectrum can be measured(1) and compared to theory. Today its spectrum remains a valuable tool for determining the values of fundamental constants and for challenging the limits of modern physics, including the validity of quantum electrodynamics and-by comparison with measurements on its antimatter counterpart, antihydrogen-the validity of CPT (charge conjugation, parity and time reversal) symmetry. Here we report spectroscopy of a pure antimatter atom, demonstrating resonant quantum transitions in antihydrogen. We have manipulated the internal spin state(2,3) of antihydrogen atoms so as to induce magnetic resonance transitions between hyperfine levels of the positronic ground state. We used resonant microwave radiation to flip the spin of the positron in antihydrogen atoms that were magnetically trapped(4-6) in the ALPHA apparatus. The spin flip causes trapped anti-atoms to be ejected from the trap. We look for evidence of resonant interaction by comparing the survival rate of trapped atoms irradiated with microwaves on-resonance to that of atoms subjected to microwaves that are off-resonance. In one variant of the experiment, we detect 23 atoms that survive in 110 trapping attempts with microwaves off-resonance (0.21 per attempt), and only two atoms that survive in 103 attempts with microwaves on-resonance (0.02 per attempt). We also describe the direct detection of the annihilation of antihydrogen atoms ejected by the microwaves., 43

Published
2012
Full Text
View/download PDF

32. The ALPHA-detector : Module Production and Assembly

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, Svante, Jorgensen, L. V., Kurchaninov, L., Madsen, N., McKenna, J. T. K., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sampson, J., Sarid, E., Seddon, D., el Nasr, S. Seif, Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., Thornhill, J., Wells, D., van der Werf, D. P., Wurtele, J. S., Yamazaki, Y., 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, Svante, Jorgensen, L. V., Kurchaninov, L., Madsen, N., McKenna, J. T. K., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sampson, J., Sarid, E., Seddon, D., el Nasr, S. Seif, Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., Thornhill, J., Wells, D., van der Werf, D. P., Wurtele, J. S., and Yamazaki, Y.

Abstract

ALPHA is one of the experiments situated at CERN's Antiproton Decelerator (AD). A Silicon Vertex Detector (SVD) is placed to surround the ALPHA atom trap. The main purpose of the SVD is to detect and locate antiproton annihilation events by means of the emitted charged pions. The SVD system is presented with special focus given to the design, fabrication and performance of the modules., AuthorCount:47

Published
2012
Full Text
View/download PDF

33. 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, Svante, 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., 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, Svante, 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.

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 annihilate. 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., 38

Published
2012
Full Text
View/download PDF

34. Search for trapped antihydrogen

Author

Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Bray, C. C., 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. J., Hydomako, R., Jonsell, Svante, Jörgensen, L. V., 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., Yamazaki, Y., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Bray, C. C., 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. J., Hydomako, R., Jonsell, Svante, Jörgensen, L. V., 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.

Abstract

We present the results of an experiment to search for trapped antihydrogen atoms with the ALPHA antihydrogen trap at the CERN Antiproton Decelerator. Sensitive diagnostics of the temperatures, sizes, and densities of the trapped antiproton and positron plasmas have been developed, which in turn permitted development of techniques to precisely and reproducibly control the initial experimental parameters. The use of a position-sensitive annihilation vertex detector, together with the capability of controllably quenching the superconducting magnetic minimum trap, enabled us to carry out a high-sensitivity and low-background search for trapped synthesised antihydrogen atoms. We aim to identify the annihilations of antihydrogen atoms held for at least 130 ms in the trap before being released over ~30 ms. After a three-week experimental run in 2009 involving mixing of 107 antiprotons with 1.3ￜ109 positrons to produce 6ￜ105 antihydrogen atoms, we have identified six antiproton annihilation events that are consistent with the release of trapped antihydrogen. The cosmic ray background, estimated to contribute 0.14 counts, is incompatible with this observation at a significance of 5.6 sigma. Extensive simulations predict that an alternative source of annihilations, the escape of mirror-trapped antiprotons, is highly unlikely, though this possibility has not yet been ruled out experimentally.

Published
2011
Full Text
View/download PDF

35. Antiparticle sources for antihydrogen production and trapping

Author

Charlton, M, Andresen, G B, Ashkezari, M D, Baquero-Ruiz, M, Bertsche, W, Bowe, P D, Bray, C C, Butler, E, Cesar, C L, Chapman, S, 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, Svante, JÞrgensen, L V, Kerrigan, S J, Kurchaninov, L, Lambo, R, Madsen, N, Menary, S, Nolan, P, Olchanski, K, Povilus, A, Pusa, P, Robicheaux, F, Sarid, E, Nasr, S Seif El, Silveira, D M, So, C, Storey, J W, Thompson, R I, Werf, D P Van Der, Wilding, D, Wurtele, J S, Yamazaki, Y, Collaboration, Alpha, Charlton, M, Andresen, G B, Ashkezari, M D, Baquero-Ruiz, M, Bertsche, W, Bowe, P D, Bray, C C, Butler, E, Cesar, C L, Chapman, S, 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, Svante, JÞrgensen, L V, Kerrigan, S J, Kurchaninov, L, Lambo, R, Madsen, N, Menary, S, Nolan, P, Olchanski, K, Povilus, A, Pusa, P, Robicheaux, F, Sarid, E, Nasr, S Seif El, Silveira, D M, So, C, Storey, J W, Thompson, R I, Werf, D P Van Der, Wilding, D, Wurtele, J S, Yamazaki, Y, and Collaboration, Alpha

Abstract

Sources of positrons and antiprotons that are currently used for the formation of antihydrogen with low kinetic energies are reviewed, mostly in the context of the ALPHA collaboration and its predecessor ATHENA. The experiments were undertaken at the Antiproton Decelerator facility, which is located at CERN. Operations performed on the clouds of antiparticles to facilitate their mixing to produce antihydrogen are described. These include accumulation, cooling and manipulation. The formation of antihydrogen and some of the characteristics of the anti-atoms that are created are discussed. Prospects for trapping antihydrogen in a magnetic minimum trap, as envisaged by the ALPHA collaboration, are reviewed.

Published
2011
Full Text
View/download PDF

36. Confinement of antihydrogen for 1,000 seconds

Author

Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Cesar, C. L., 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, Svante, Kemp, S. L., Kurchaninov, L., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Pusa, P., Rasmussen, C. O., 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., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Cesar, C. L., 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, Svante, Kemp, S. L., Kurchaninov, L., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Pusa, P., Rasmussen, C. O., 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.

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 1,000 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 charge-parity-time reversal symmetry and cooling to temperatures where gravitational effects could become apparent., authorCount :40

Published
2011
Full Text
View/download PDF

37. Autoresonant Excitation of Antiproton Plasmas

Author

Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Carpenter, P. T., Cesar, C. L., Chapman, S., Charlton, M., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Hangst, J. S., Hardy, W. N., Hayden, M. E., Humphries, A. J., Hurt, J. L., Hydomako, R., Jonsell, Svante, 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., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Carpenter, P. T., Cesar, C. L., Chapman, S., Charlton, M., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Hangst, J. S., Hardy, W. N., Hayden, M. E., Humphries, A. J., Hurt, J. L., Hydomako, R., Jonsell, Svante, 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., and Yamazaki, Y.

Abstract

We demonstrate controllable excitation of the center-of-mass longitudinal motion of a thermal antiproton plasma using a swept-frequency autoresonant drive. When the plasma is cold, dense, and highly collective in nature, we observe that the entire system behaves as a single-particle nonlinear oscillator, as predicted by a recent theory. In contrast, only a fraction of the antiprotons in a warm plasma can be similarly excited. Antihydrogen was produced and trapped by using this technique to drive antiprotons into a positron plasma, thereby initiating atomic recombination, authorCount :37

Published
2011
Full Text
View/download PDF

38. Search for trapped antihydrogen in ALPHA

Author

Madsen, N, Andresen, G B, Ashkezari, M D, Baquero-Ruiz, M, Bertsche, W, Bowe, P D, Bray, C C, 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, Hayden, M R, Humphries, A J, Hydomako, R, Jonsell, Svante, Jørgensen, L V, Kurchaninov, L, Lambo, R, 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, Wurtele, J S, Yamazaki, Y, Madsen, N, Andresen, G B, Ashkezari, M D, Baquero-Ruiz, M, Bertsche, W, Bowe, P D, Bray, C C, 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, Hayden, M R, Humphries, A J, Hydomako, R, Jonsell, Svante, Jørgensen, L V, Kurchaninov, L, Lambo, R, 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, Wurtele, J S, and Yamazaki, Y

Abstract

Antihydrogen spectroscopy promises precise tests of the symmetry of matter and antimatter, and can possibly offer new insights into the baryon asymmetry of the universe. Antihydrogen is, however, difficult to synthesize and is produced only in small quantities. The ALPHA collaboration is therefore pursuing a path towards trapping cold antihydrogen to permit the use of precision atomic physics tools to carry out comparisons of antihydrogen and hydrogen. ALPHA has addressed these challenges. Control of the plasma sizes has helped to lower the influence of the multipole field used in the neutral atom trap, and thus lowered the temperature of the created atoms. Finally, the first systematic attempt to identify trapped antihydrogen in our system is discussed. This discussion includes special techniques for fast release of the trapped anti-atoms, as well as a silicon vertex detector to identify antiproton annihilations. The silicon detector reduces the background of annihilations, including background from antiprotons that can be mirror trapped in the fields of the neutral atom trap. A description of how to differentiate between these events and those resulting from trapped antihydrogen atoms is also included.

Published
2011
Full Text
View/download PDF

39. Antimatter transport processes

Author

Van Der Werf, D. P., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Bray, C. C., 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. J., Hydomako, R., Jonsell, Svante, Jørgensen, L. V., 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., Wurtele, J. S., Yamazaki, Y., Van Der Werf, D. P., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Bray, C. C., 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. J., Hydomako, R., Jonsell, Svante, Jørgensen, L. V., 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., Wurtele, J. S., and Yamazaki, Y.

Abstract

A comparison of the 1S-2S transitions of hydrogen and antihydrogen will yield a stringent test of CPT conservation. Necessarily, the antihydrogen atoms need to be trapped to perform high precision spectroscopy measurements. Therefore, an approximately 0.75 T deep neutral atom trap, equivalent to about 0.5 K for ground state (anti)hydrogen atoms, has been superimposed on a Penning-Malmberg trap in which the anti-atoms are formed. The antihydrogen atoms are produced following a number of steps. A bunch of antiprotons from the CERN Antiproton Decelerator is caught in a Penning-Malmberg trap and subsequently sympathetically cooled and then compressed using rotating wall electric fields. A positron plasma, formed in a separate accumulator, is transported to the main system and also compressed. Antihydrogen atoms are then formed by mixing the antiprotons and positrons. The velocity of the anti-atoms, and their binding energies, will strongly depend on the initial conditions of the constituent particles, for example their temperatures and densities, and on the details of the mixing process. In this paper the complete lifecycle of antihydrogen atoms will be presented, starting with the production of the constituent antiparticles and the description of the manipulations necessary to prepare them appropriately for antihydrogen formation. The latter will also be described, as will the possible fates of the anti-atoms.

Published
2010
Full Text
View/download PDF

40. Evaporative Cooling of Antiprotons to Cryogenic Temperatures

Author

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, Svante, 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., 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, Svante, 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.

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 CPT test on trapped antihydrogen is a long-standing goal.

Published
2010
Full Text
View/download PDF

41. Evaporative cooling of antiprotons for the production of trappable antihydrogen

Author

Silveira, D. M., primary, Andresen, G. B., additional, Ashkezari, M. D., additional, Baquero-Ruiz, M., additional, Bertsche, W., additional, Bowe, P. D., additional, Butler, E., additional, Cesar, C. L., additional, Chapman, S., additional, Charlton, M., 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, Hydomako, R., additional, Jonsell, S., additional, Kurchaninov, L., additional, Madsen, N., additional, Menary, S., additional, Nolan, P., additional, Olchanski, K., additional, Olin, A., additional, Povilus, A., additional, Pusa, P., additional, Robicheaux, F., additional, Sarid, E., additional, So, C., additional, Storey, J. W., additional, Thompson, R. I., additional, van der Werf, D. P., additional, and Wurtele, J. S., additional

Published
2013
Full Text
View/download PDF

42. Electron plasmas as a diagnostic tool for hyperfine spectroscopy of antihydrogen

Author

Friesen, T., primary, Amole, C., additional, Ashkezari, M. D., additional, Baquero-Ruiz, M., additional, Bertsche, W., additional, Bowe, P. D., additional, Butler, E., additional, Capra, A., additional, Cesar, C. L., additional, Charlton, M., additional, Deller, A., additional, Evetts, N., additional, Eriksson, S., additional, Fajans, J., 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, Madsen, N., additional, McKenna, J. T. K., additional, Menary, S., additional, Napoli, S. C., additional, Olchanski, K., additional, Olin, A., additional, Pusa, P., additional, Rasmussen, C. O., additional, Robicheaux, F., additional, Sarid, E., additional, Silveira, D. M., additional, So, C., additional, Stracka, S., additional, Thompson, R. I., additional, van der Werf, D. P., additional, and Wurtele, J. S., additional

Published
2013
Full Text
View/download PDF

43. Resonant quantum transitions in trapped antihydrogen atoms

Author

Amole, C., primary, Ashkezari, M. D., additional, Baquero-Ruiz, M., additional, Bertsche, W., additional, Bowe, P. D., additional, Butler, E., additional, Capra, A., additional, Cesar, C. L., additional, Charlton, M., additional, Deller, A., additional, Donnan, P. H., 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, Humphries, A. J., 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, Sarid, E., additional, Shields, C. R., additional, Silveira, D. M., additional, Stracka, S., additional, So, C., additional, Thompson, R. I., additional, van der Werf, D. P., additional, and Wurtele, J. S., additional

Published
2012
Full Text
View/download PDF

44. Discriminating between antihydrogen and mirror-trapped antiprotons in a minimum-B trap

Author

Amole, C, primary, Andresen, G B, additional, Ashkezari, M D, additional, Baquero-Ruiz, M, additional, Bertsche, W, additional, Butler, E, additional, Cesar, C L, additional, Chapman, S, additional, Charlton, M, additional, Deller, A, 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, Humphries, A J, additional, Hydomako, R, additional, Kurchaninov, L, additional, Jonsell, S, additional, Madsen, N, additional, Menary, S, 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, Storey, J W, additional, Thompson, R I, additional, van der Werf, D P, additional, and Wurtele, J S, additional

Published
2012
Full Text
View/download PDF

45. The ALPHA – detector: Module Production and Assembly

Author

Andresen, G B, primary, Ashkezari, M D, additional, Baquero-Ruiz, M, additional, Bertsche, W, additional, Bowe, P D, additional, Butler, E, additional, Cesar, C L, additional, Chapman, S, additional, Charlton, M, additional, Deller, A, 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, Humphries, A J, additional, Hydomako, R, additional, Jenkins, M J, additional, Jonsell, S, additional, JØrgensen, L V, additional, Kurchaninov, L, additional, Madsen, N, additional, McKenna, J T K, additional, Menary, S, additional, Nolan, P, additional, Olchanski, K, additional, Olin, A, additional, Povilus, A, additional, Pusa, P, additional, Robicheaux, F, additional, Sampson, J, additional, Sarid, E, additional, Seddon, D, additional, Nasr, S Seif el, additional, Silveira, D M, additional, So, C, additional, Storey, J W, additional, Thompson, R I, additional, Thornhill, J, additional, Wells, D, additional, Werf, D P van der, additional, Wurtele, J S, additional, and Yamazaki, Y, additional

Published
2012
Full Text
View/download PDF

46. Antiparticle plasmas for antihydrogen trapping

Author

Charlton, M., primary, Andresen, G. B., additional, Ashkezari, M. D., additional, Baquero-Ruiz, M., additional, Bertsche, W., additional, Bowe, P. D., additional, Butler, E., additional, Carpenter, P. T., additional, Cesar, C. L., additional, Chapman, S., 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, Hayano, R. S., additional, Hayden, M. E., additional, Humphries, A. J., additional, Hurt, J. L., additional, Hydomako, R., additional, Jonsell, S., additional, Kurchaninov, L., additional, Madsen, N., additional, Menary, S., 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, Storey, J. W., additional, Thompson, R. I., additional, van der Werf, D. P., additional, Wurtele, J. S., additional, and Yamazaki, Y., additional

Published
2012
Full Text
View/download PDF

47. Search for trapped antihydrogen in ALPHAThis paper was presented at the International Conference on Precision Physics of Simple Atomic Systems, held at École de Physique, les Houches, France, 30 May – 4 June, 2010.

Author

Madsen, N., primary, Andresen, G. B., additional, Ashkezari, M. D., additional, Baquero-Ruiz, M., additional, Bertsche, W., additional, Bowe, P. D., additional, Bray, C., additional, Butler, E., additional, Cesar, C. L., additional, Chapman, S., additional, Charlton, M., 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, Humphries, A. J., additional, Hydomako, R., additional, Jonsell, S., additional, Jørgensen, L. V., additional, Kurchaninov, L., additional, Lambo, R., additional, Menary, S., additional, Nolan, P., additional, Olchanski, K., additional, Olin, A., additional, Povilus, A., additional, Pusa, P., additional, Robicheaux, F., additional, Sarid, E., additional, El Nasr, S. Seif, additional, Silveira, D. M., additional, So, C., additional, Storey, J. W., additional, Thompson, R. I., additional, van der Werf, D. P., additional, Wurtele, J. S., additional, and Yamazaki, Y., additional

Published
2011
Full Text
View/download PDF

48. Antimatter transport processes

Author

Van Der Werf, D P, primary, Andresen, G B, additional, Ashkezari, M D, additional, Baquero-Ruiz, M, additional, Bertsche, W, additional, Bowe, P D, additional, Bray, C C, additional, Butler, E, additional, Cesar, C L, additional, Chapman, S, additional, Charlton, M, additional, Fajans, J, additional, Friesen, T, additional, Fujiwara, M C, additional, Gill, D R, additional, Hangst, J S, additional, Hardy, W N, additional, Hayano, R S, additional, Hayden, M E, additional, Humphries, A J, additional, Hydomako, R, additional, Jonsell, S, additional, Jørgensen, L V, additional, Kurchaninov, L, additional, Lambo, R, additional, Madsen, N, additional, Menary, S, 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, Storey, J W, additional, Thompson, R I, additional, Wurtele, J S, additional, and Yamazaki, Y, additional

Published
2010
Full Text
View/download PDF

49. Evaporative Cooling of Antiprotons to Cryogenic Temperatures

Author

Andresen, G. B., primary, Ashkezari, M. D., additional, Baquero-Ruiz, M., additional, Bertsche, W., additional, Bowe, P. D., additional, Butler, E., additional, Cesar, C. L., additional, Chapman, S., additional, Charlton, M., additional, Fajans, J., additional, Friesen, T., additional, Fujiwara, M. C., additional, Gill, D. R., additional, Hangst, J. S., additional, Hardy, W. N., additional, Hayano, R. S., additional, Hayden, M. E., additional, Humphries, A., additional, Hydomako, R., additional, Jonsell, S., additional, Kurchaninov, L., additional, Lambo, R., additional, Madsen, N., additional, Menary, S., 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, Storey, J. W., additional, Thompson, R. I., additional, van der Werf, D. P., additional, Wilding, D., additional, Wurtele, J. S., additional, and Yamazaki, Y., additional

Published
2010
Full Text
View/download PDF

50. Evaporative cooling of antiprotons for the production of trappable antihydrogen.

Author

Silveira, D. M., 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., Hayden, M. E., Hydomako, R., Jonsell, S., and Kurchaninov, L.

Subjects
EVAPORATIVE cooling, ANTIPROTONS, ION traps, ANTIHYDROGEN, PARTICLES (Nuclear physics), TEMPERATURE measurements, DISTRIBUTION (Probability theory)
Abstract

We describe the implementation of evaporative cooling of charged particles in the ALPHA apparatus. Forced evaporation has been applied to cold samples of antiprotons held in Malmberg-Penning traps. Temperatures on the order of 10 K were obtained, while retaining a significant fraction of the initial number of particles. We have developed a model for the evaporation process based on simple rate equations and applied it succesfully to the experimental data. We have also observed radial re-distribution of the clouds following evaporation, explained by simple conservation laws. We discuss the relevance of this technique for the recent demonstration of magnetic trapping of antihydrogen. [ABSTRACT FROM AUTHOR]

Published
2013
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results