[Triumf-seminars] TRIUMF Colloquium today at 14:00

[TRIUMF Seminars]

Date/Time: Mon 2022-07-25 at 14:00

Location:  Auditorium/ Hybrid  

Speaker:   Eberhard Widmann (Stefan Meyer Institute, Vienna)

Title:     Hyperfine spectroscopy of antihydrogen and hydrogen for tests of CPT and Lorentz invariance

Abstract: Join Zoom Meeting
https://uvic.zoom.us/j/87557183733?pwd=UVpkaHQyYW1PZ3lsckpEL0Zac0x3UT09

Meeting ID: 875 5718 3733
Password: 752187
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The primary interest in antihydrogen, the bound state of an antiproton and a positron, comes from the fact that its properties can be compared to ordinary hydrogen, one of the best studied atoms experimentally, in order to test the fundamental CPT symmetry which is one of the cornerstones of the Standard Model of particle physics. Among the two best-known transitions in hydrogen is the ground-state hyperfine transition nu_HF with a relative precision of better than 1E-12.

The ASACUSA collaboration at CERN has proposed a measurement of nu_HF in a beam, which allows to perform the experiment in a region far away from the strong magnetic fields needed for antihydrogen creation. The current status of creating a polarized beam of antihydrogen will be described, and the prospects of a measurement of nu_HF with an initial precision of 1 ppm aimed for.

Initially with the aim to establish the in-beam method, ASACUSA has performed a measurement of nu_HF of ordinary hydrogen using a polarized beam of 50 K temperature and the same Rabi spectroscopy setup as will be used for antihydrogen and obtained a precision of 2.7 ppb. Within the Standard Model Extension (SME) framework that describes potential Lorentz invariance and CPT violation scenarios, also measurements using ordinary atoms can be used to constrain symmetry-violating SME coefficients. Experiments are ongoing to measure the orientation dependence of the static magnetic field for hydrogen hyperfine measurement, and the hyperfine structure of deuterium.

A further significant improvement in precision needs much slower atoms. The GRASIAN collaboration aims at cooling hydrogen to temperatures of submicro-Kelvin where it forms gravitational quantum states when reflected from a surface by the Casimir-Polder potential. Hyperfine experiments at such velocities can potentially reach accuracies of 1E-12 or better and can, due to the quantum nature of the reflection, ultimately also be applied to antihydrogen.

Hybrid Colloquium.
Stimulants available 15 minutes before the talk.

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General TRIUMF seminar information available at http://www.triumf.ca/home/upcoming-events/about-seminars-lectures