ALPHA Experiment

The ALPHA-2 apparatus - facilitating experimentation with trapped antihydrogen

Refereed Publication

21 Jan 2025

This paper describes the ALPHA-2 apparatus, used at the CERN Antiproton Decelerator facility for the study of trapped antihydrogen

Published in

Nucl. Inst. & Meth. Phys. A 1072 (2025) 170194

R. Akbari and B.X.R. Alves and C.J. Baker and M. Baquero-Ruiz and W. Bertsche and E. Butler and C. Burrows and A. Capra and C.L. Cesar and M. Charlton and R. Collister and A. Cridland and S. Eriksson and A. Evans and L.T. Evans and N. Evetts and J. Fajans and T. Friesen and M.C. Fujiwara and D.R. Gill and P. Grandemange and P. Granum and A. Gutierrez and J.S. Hangst and M.E. Hayden and D. Hodgkinson and C.A. Isaac and A. Ishida and M.A. Johnson and J.M. Jones and S.A. Jones and S. Jonsell and A. Khramov and L. Kurchaninov and A. Little and N. Madsen and D. Maxwell and J.T.K. McKenna and S

Precision spectroscopy of the hyperfine components of the 1S--2S transition in antihydrogen

Refereed Publication

17 Jan 2025

The antimatter equivalent of atomic hydrogen—antihydrogen—is an outstanding testbed for precision studies of matter–antimatter symmetry. Here we report on the simultaneous observation of both accessible hyperfine components of the 1S–2S transition in trapped antihydrogen. We determine the 2S hyperfine splitting in antihydrogen and—by comparing our results with those obtained in hydrogen—constrain the charge–parity–time-reversal symmetry-violating coefficients in the standard model extension framework.

Published in

Nature Physics (2025)

Baker, C. J. and Bertsche, W. and Capra, A. and Carruth, C. and Cesar, C. L. and Charlton, M. and Christensen, A. and Collister, R. and Cridland Mathad, A. and Eriksson, S. and Evans, A. and Evetts, N. and Fajans, J. and Friesen, T. and Fujiwara, M. C. and Gill, D. R. and Grandemange, P. and Granum, P. and Hangst, J. S. and Hardy, W. N. and Hayden, M. E. and Hodgkinson, D. and Hunter, E. and Isaac, C. A. and Johnson, M. A. and Jones, J. M. and Jones, S. A. and Jonsell, S. and Khramov, A. and Kurchaninov, L. and Madsen, N. and Maxwell, D. and McKenna, J. T. K. and Menary, S. and Momose, T. and

On the Dynamics of Adiabatically Cooled Antihydrogen in an Octupole-Based Ioﬀe-Pritchard Magnetic Trap

Theses

01 Jun 2022

Antihydrogen is now routinely formed in ALPHA by combination of antiproton and
positron plasmas. Formed anti-atoms with energy <∼0.5 K are trapped in an octupole-
based Ioﬀe-Pritchard magnetic trap. Reducing trapped antihydrogen energy is expected
to increase precision in experiments that measure fundamental antihydrogen properties
for precise comparison to hydrogen. Cooling is expected to permit confinement in a

Published in

University of Manchester

Danielle L. Hodgkinson

Measurements of Penning-Malmberg trap patch potentials and associated performance degradation

Refereed Publication

16 Jan 2024

Antiprotons created by laser ionization of antihydrogen are observed to rapidly escape the ALPHA trap. Further, positron plasmas heat more quickly after the trap is illuminated by laser light for several hours. These phenomena can be caused by patch potentials—variations in the electrical potential along metal surfaces.

Published in

Physsical Review Research Vol. 6, Iss. 1

C. J. Baker, W. Bertsche, A. Capra, C. L. Cesar, M. Charlton, A. Christensen, R. Collister, A. Cridland Mathad, S. Eriksson, A. Evans, N. Evetts, J. Fajans, T. Friesen, M. C. Fujiwara, D. R. Gill, P. Grandemange, P. Granum, J. S. Hangst, M. E. Hayden, D. Hodgkinson, E. D. Hunter, C. A. Isaac, M. A. Johnson, J. Jones, S. A. Jones, S. Jonsell, A. Khramov, L. Kurchaninov, H. Landsberger, N. Madsen, D. Maxwell, J. T. K. McKenna, S. Menary, T. Momose, P. S. Mullan, J. J. Munich, K. Olchanski, A. Olin, J. Peszka, A. Powell, P. Pusa, C.Ø. Rasmussen, F. Robicheaux, R. L. Sacramento, M. Sameed, E