1. Measuring the hyperfine splitting in anti-hydrogen to test for CPT violation Martin Roelfs Summer Student Session 13 th of August, 2015 Supervisor: Chloé Malbrunot Image credits: European Space Agency & NASA

2. Matter : Anti-Matter We only need a 1:10 -10 asymmetry since matter:photon density from astronomical measurements is ~6 x 10 -10. Image credit: interactions.org

3. Standard model: exactly 50:50  Why? Because it has CPT invariance.  We need CPT violation to explain the dominance of matter Something’s gotto give

4. Two parts of the experiment Hydrogen BeamAnti-Hydrogen Beam

5. Outline  Hyperfine splitting in H and Ħ  Hydrogen beam setup  Outlook

6. Hyperfine Splitting Hyperfine splitting gives rise to the famous 21 cm line Image credit: NASA APOD

7. Origin of Hyperfine splitting Is this the same wavelength for anti-hydrogen?

8. Hyperfine splitting of Ground State Without external fieldExternal B field Image credit: pha.jhu.edu

9. Polarization Image credits: cds.cern.ch

10. Experimental Outline PolarizerAnalyzerSpin flipDetector Mixed State High/Low Low only Mixed

11. Meanwhile, at the detector…

12. Hydrogen beam setup Hydrogen plasma Polarizing sextupole Chopper Spin flip cavity Analysing sextupole Mass spectrometer

13. Hydrogen beam setup Hydrogen plasma Polarizing sextupole Chopper Analysing sextupole Spin flip cavity Mass spectrometer

14. Comparison with anti-hydrogen Hydrogen plasma Polarizing sextupole Chopper Analysing sextupole Spin flip cavity Mass spectrometer

15. Hydrogen Plasma

16. Future – permanent sextupoles Replace superconducting sextupoles by 1T permanent magnet array Reason: superconducting sextupoles is in use at the antimatter factory

17. Future  Characterize H beam  Velocity distribution  Build the analyzing sextupoles  Include RF cavity and analyzing sextupoles in setup  Start measurements!  Measure the σ and π resonances

18. Thank you for your attention

19. Supporting Slides

20. Lorentz Violation -> CPT Violation  If CPT violation: no Lorentz Invariance!

22. Compare Ħ to H CPT turns matter into anti-matter

23. Addition of angular momentum