@article {91, title = {Hyperfine spectroscopy of hydrogen and antihydrogen in ASACUSA}, journal = {Hyperfine Interactions}, volume = {240}, year = {2018}, month = {Dec}, pages = {5}, abstract = {

The ASACUSA collaboration at the Antiproton Decelerator of CERN aims at a precise measurement of the antihydrogen ground-state hyperfine structure as a test of the fundamental CPT symmetry. A beam of antihydrogen atoms is formed in a CUSP trap, undergoes Rabi-type spectroscopy and is detected downstream in a dedicated antihydrogen detector. In parallel measurements using a polarized hydrogen beam are being performed to commission the spectroscopy apparatus and to perform measurements of parameters of the Standard Model Extension (SME). The current status of antihydrogen spectroscopy is reviewed and progress of ASACUSA is presented.

}, issn = {1572-9540}, doi = {10.1007/s10751-018-1536-9}, url = {https://doi.org/10.1007/s10751-018-1536-9}, author = {Widmann, E. and Amsler, C. and Arguedas Cuendis, S. and Breuker, H. and Diermaier, M. and Dupre, P. and Evans, C. and Fleck, M. and Gligorova, A. and Higaki, H. and Kanai, Y. and Kolbinger, B. and Kuroda, N. and Leali, M. and Leite, A. M. M. and M{\"a}ckel, V. and Malbrunot, C. and Mascagna, V. and Massiczek, O. and Matsuda, Y. and Murtagh, D. J. and Nagata, Y. and Nanda, A. and Phan, D. and Sauerzopf, C. and Simon, M. C. and Tajima, M. and Spitzer, H. and Strube, M. and Ulmer, S. and Venturelli, L. and Wiesinger, M. and Yamazaki, Y. and Zmeskal, J.} } @article {93, title = {Recent Developments from ASACUSA on Antihydrogen Detection}, journal = {EPJ Web of Conferences}, volume = {181}, year = {2018}, pages = {01003}, doi = {10.1051/epjconf/201818101003}, url = {https://doi.org/10.1051/epjconf/201818101003}, author = {Kolbinger, B. and Amsler, C. and Breuker, H. and Diermaier, M. and Dupre, P. and Fleck, M. and Gligorova, A. and Higaki, H. and Kanai, Y. and Kobayashi, T. and Leali, M. and M{\"a}ckel, V. and Malbrunot, C. and Mascagna, V. and Massiczek, O. and Matsuda, Y. and Murtagh, D.J. and Nagata, Y. and Sauerzopf, C. and Simon, M.C. and Tajima, M. and Ulmer, S. and Kuroda, N. and Venturelli, L. and Widmann, E. and Yamazaki, Y. and Zmeskal, J.} } @article {79, title = {In-beam measurement of the hydrogen hyperfine splitting - towards antihydrogen spectroscopy}, journal = {Nature Communications}, volume = {8}, year = {2017}, month = {12/06/2017}, pages = {1{\textendash}9}, abstract = {

Antihydrogen, the lightest atom consisting purely of antimatter, is an ideal laboratory to study the CPT symmetry by comparison to hydrogen. With respect to absolute precision, transitions within the ground-state hyperfine structure (GS-HFS) are most appealing by virtue of their small energy separation. ASACUSA proposed employing a beam of cold antihydrogen atoms in a Rabi-type experiment to determine the GS-HFS in a field-free region. Here we present a measurement of the zero-field hydrogen GS-HFS using the spectroscopy apparatus of ASACUSA{\textquoteright}s antihydrogen experiment. The measured value of {\$}\backslashnu{\_}\backslashmathrm{\{}HF{\}}{\$}={\$}1{\~{}}420{\~{}}405{\~{}}748.4(3.4)(1.6){\~{}}\backslashtextrm{\{}Hz{\}}{\$} with a relative precision of {\$}\backslashDelta{\$}{\$}\backslashnu{\_}\backslashmathrm{\{}HF{\}}{\$}/{\$}\backslashnu{\_}\backslashmathrm{\{}HF{\}}{\$}={\$}2.7\backslashtimes10{\^{}}{\{}-9{\}}{\$} constitutes the most precise determination of this quantity in a beam and verifies the developed spectroscopy methods for the antihydrogen HFS experiment to the ppb level. Together with the recently presented observation of antihydrogen atoms {\$}2.7{\~{}}\backslashtextrm{\{}m{\}}{\$} downstream of the production region, the prerequisites for a measurement with antihydrogen are now available within the ASACUSA collaboration.

}, doi = {10.1038/ncomms15749}, url = {https://doi.org/10.1038/ncomms15749}, author = {Diermaier, M. and Jepsen, C. B. and Kolbinger, B. and Malbrunot, C. and Massiczek, O. and Sauerzopf, C. and Simon, M. C. and Zmeskal, J. and Widmann, E.} } @article {80, title = {Towards measuring the ground state hyperfine splitting of antihydrogen {\textendash} a progress report}, journal = {Hyperfine Interactions}, volume = {237}, year = {2016}, month = {Jun}, pages = {103}, abstract = {We report the successful commissioning and testing of a dedicated field-ioniser chamber for measuring principal quantum number distributions in antihydrogen as part of the ASACUSA hyperfine spectroscopy apparatus. The new chamber is combined with a beam normalisation detector that consists of plastic scintillators and a retractable passivated implanted planar silicon (PIPS) detector.}, issn = {1572-9540}, doi = {10.1007/s10751-016-1309-2}, url = {https://doi.org/10.1007/s10751-016-1309-2}, author = {Sauerzopf, C. and Capon, A. A. and Diermaier, M. and Dupre, P. and Higashi, Y. and Kaga, C. and Kolbinger, B. and Leali, M. and Lehner, S. and Rizzini, E. Lodi and Malbrunot, C. and Mascagna, V. and Massiczek, O. and Murtagh, D. J. and Nagata, Y. and Radics, B. and Simon, M. C. and Suzuki, K. and Tajima, M. and Ulmer, S. and Vamosi, S. and Gorp, S. van and Zmeskal, J. and Breuker, H. and Higaki, H. and Kanai, Y. and Kuroda, N. and Matsuda, Y. and Venturelli, L. and Widmann, E. and Yamazaki, Y.} } @article {75, title = {The ASACUSA CUSP: an antihydrogen experiment}, journal = {Hyperfine Interactions}, volume = {235}, year = {2015}, pages = {13{\textendash}20}, abstract = {In order to test CPT symmetry between antihydrogen and its counterpart hydrogen, the ASACUSA collaboration plans to perform high precision microwave spectroscopy of ground-state hyperfine splitting of antihydrogen atom in-flight. We have developed an apparatus ({\textquoteleft}{\textquoteleft}cusp trap{\textquoteright}{\textquoteright}) which consists of a superconducting anti-Helmholtz coil and multiple ring electrodes. For the preparation of slow antiprotons and positrons, Penning-Malmberg type traps were utilized. The spectrometer line was positioned downstream of the cusp trap. At the end of the beamline, an antihydrogen beam detector was located, which comprises an inorganic Bismuth Germanium Oxide (BGO) single-crystal scintillator housed in a vacuum duct and surrounding plastic scintillators. A significant fraction of antihydrogen atoms flowing out the cusp trap were detected.}, issn = {1572-9540}, doi = {10.1007/s10751-015-1205-1}, url = {http://dx.doi.org/10.1007/s10751-015-1205-1}, author = {Kuroda, N. and Ulmer, S. and Murtagh, D. J. and Gorp, S. and Nagata, Y. and Diermaier, M. and Federmann, S. and Leali, M. and Malbrunot, C. and Mascagna, V. and Massiczek, O. and Michishio, K. and Mizutani, T. and Mohri, A. and Nagahama, H. and Ohtsuka, M. and Radics, B. and Sakurai, S. and Sauerzopf, C. and Suzuki, K. and Tajima, M. and Torii, H. A. and Venturelli, L. and W{\"u}nschek, B. and Zmeskal, J. and Zurlo, N. and Higaki, H. and Kanai, Y. and Rizzini, E. Lodi and Nagashima, Y. and Matsuda, Y. and Widmann, E. and Yamazaki, Y.} } @article {72, title = {An atomic hydrogen beam to test ASACUSA{\textquoteright}s apparatus for antihydrogen spectroscopy}, journal = {Hyperfine Interactions}, volume = {233}, year = {2015}, pages = {35-40}, keywords = {Antihydrogen, Atomic hydrogen, Ground state hyperfine structure}, issn = {0304-3843}, doi = {10.1007/s10751-015-1151-y}, url = {http://dx.doi.org/10.1007/s10751-015-1151-y}, author = {Diermaier, M. and Caradonna, P. and Kolbinger, B. and Malbrunot, C. and Massiczek, O. and Sauerzopf, C. and Simon, M.C. and Wolf, M. and Zmeskal, J. and Widmann, E.} } @article {56, title = {A source of antihydrogen for in-flight hyperfine spectroscopy}, journal = {Nat Commun}, volume = {5}, year = {2014}, month = {21/01/2014}, abstract = {

Antihydrogen, a positron bound to an antiproton, is the simplest antiatom. Its counterpart{\textemdash}hydrogen{\textemdash}is one of the most precisely investigated and best understood systems in physics research. High-resolution comparisons of both systems provide sensitive tests of CPT symmetry, which is the most fundamental symmetry in the Standard Model of elementary particle physics. Any measured difference would point to CPT violation and thus to new physics. Here we report the development of an antihydrogen source using a cusp trap for in-flight spectroscopy. A total of 80 antihydrogen atoms are unambiguously detected 2.7 m downstream of the production region, where perturbing residual magnetic fields are small. This is a major step towards precision spectroscopy of the ground-state hyperfine splitting of antihydrogen using Rabi-like beam spectroscopy.

}, url = {http://dx.doi.org/10.1038/ncomms4089}, author = {Kuroda, N. and Ulmer, S. and Murtagh, D. J. and Van Gorp, S. and Nagata, Y. and Diermaier, M. and Federmann, S. and Leali, M. and Malbrunot, C. and Mascagna, V. and Massiczek, O. and Michishio, K. and Mizutani, T. and Mohri, A. and Nagahama, H. and Ohtsuka, M. and Radics, B. and Sakurai, S. and Sauerzopf, C. and Suzuki, K. and Tajima, M. and Torii, H. A. and Venturelli, L. and Wu{\textasciidieresis}nschek, B. and Zmeskal, J. and Zurlo, N. and Higaki, H. and Kanai, Y. and Lodi Rizzini, E. and Nagashima, Y. and Matsuda, Y. and Widmann, E. and Yamazaki, Y.} } @article {67, title = {Spectroscopy apparatus for the measurement of the hyperfine structure of antihydrogen}, journal = {Hyperfine Interactions}, year = {2014}, pages = {1-6}, keywords = {Antihydrogen, CPT symmetry, Hyperfine spectroscopy}, issn = {0304-3843}, doi = {10.1007/s10751-014-1013-z}, url = {http://dx.doi.org/10.1007/s10751-014-1013-z}, author = {Malbrunot, C. and Caradonna, P. and Diermaier, M. and Dilaver, N. and Friedreich, S. and Kolbinger, B. and Lehner, S. and Lundmark, R. and Massiczek, O. and Radics, B. and Sauerzopf, C. and Simon, M. and Widmann, E. and Wolf, M. and W{\"u}nschek, B. and Zmeskal, J.} } @article {66, title = {Towards a spin polarized antihydrogen beam}, journal = {Hyperfine Interactions}, year = {2014}, pages = {1-10}, keywords = {Antihydrogen, Atomic beam, CPT invariance, Rydberg atom}, issn = {0304-3843}, doi = {10.1007/s10751-014-1016-9}, url = {http://dx.doi.org/10.1007/s10751-014-1016-9}, author = {Kuroda, N. and Ulmer, S. and Murtagh, D.J. and Van Gorp, S. and Nagata, Y. and Diermaier, M. and Federmann, S. and Leali, M. and Malbrunot, C. and Mascagna, V. and Massiczek, O. and Michishio, K. and Mizutani, T. and Mohri, A. and Nagahama, H. and Ohtsuka, M. and Radics, B. and Sakurai, S. and Sauerzopf, C. and Suzuki, K. and Tajima, M. and Torii, H.A. and Venturelli, L. and W{\"u}nschek, B. and Zmeskal, J. and Zurlo, N. and Higaki, H. and Kanai, Y. and Lodi-Rizzini, E. and Nagashima, Y. and Matsuda, Y. and Widmann, E. and Yamazaki, Y.} } @article {54, title = {Measurement of the hyperfine structure of antihydrogen in a beam}, journal = {Hyperfine Interactions}, volume = {215}, year = {2013}, pages = {1-8}, keywords = {Antihydrogen, CPT, Precision spectroscopy}, issn = {0304-3843}, doi = {10.1007/s10751-013-0809-6}, url = {http://dx.doi.org/10.1007/s10751-013-0809-6}, author = {Widmann, E. and Diermaier, M. and Juhasz, B. and Malbrunot, C. and Massiczek, O. and Sauerzopf, C. and Suzuki, K. and W{\"u}nschek, B. and Zmeskal, J. and Federmann, S. and Kuroda, N. and Ulmer, S. and Yamazaki, Y.} }