Hyperfine spectroscopy of hydrogen and antihydrogen in ASACUSA

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

Cold and stable antimatter for fundamental physics

“…107) In the case of the p charge-to-mass ratio, 146) the length of the bar is well defined, while the right end is the cyclotron frequency, which is proportional to the magnetic field. 147) For a more rigorous comparison, one possible way is to convert to the upper limit of the SME coefficients. 126) In order for free-fall to be practically observable, a good guess would be to expect g"t to be comparable to, or larger than, v T , where g is the gravitational acceleration (F 9.8 m/s 2 ), "t the observation time and v T a typical velocity due to thermal motion of antihydrogen atoms.…”

“…16 summarize several particle properties related to the advancements of cold antimatter research. 37 , 107 , 126 , 145 – 147 ) The latest values discussed in §6 are listed together with the data in Review of Particle Physics 2018. 37 ) The magnetic moments of the antiproton and the proton are now known to agree like , a three orders of magnitude improvement that given in Ref.…”

“… 107 ) In the case of the charge-to-mass ratio, 146 ) the length of the bar is well defined, while the right end is the cyclotron frequency, which is proportional to the magnetic field. 147 ) For a more rigorous comparison, one possible way is to convert to the upper limit of the SME coefficients. 126 )…”

Progress Towards Ramsey Hyperfine Spectroscopy in ASACUSA

“…The ASACUSA-CUSP (Atomic Spectroscopy And Collisions Using Slow Antiprotons) antihydrogen experiment based at the Antiproton Decelerator facility of CERN aims to perform precise tests of CPT symmetry by measuring the ground-state hyperfine structure (GS-HFS) of antihydrogen atoms and comparing it with that of hydrogen. 1 A brief account on the status of ASACUSA's antihydrogen program can be found within these proceedings. 2 The currently applied Rabi-type beam-spectroscopy method can be made more precise by the implementation of Ramsey's technique of using two separated oscillatory fields.…”

Rabi Experiments on the σ and π Hyperfine Transitions in Hydrogen and Status of ASACUSA’s Antihydrogen Program

“…By operating at sufficiently high B ext (e.g., 23/69/115 µT as in Ref. 15) the systematic shifts and related uncertainties can easily be kept below ∼ 10 ppb, an acceptable level for the anticipated first-stage results on H. A measurement of a single pair of a π 1 and σ 1 transitions in this regime of B ext provides a reliable way to determine the zero-field splitting from a calculation, 15 i.e., without extrapolating to zero field by a fit. Thus, the present apparatus is well suited for a first Rabi-type SME-sensitive H hyperfine-structure measurement.…”