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Uniwersytet Jagielloński

Zakład Optyki Atomowej. Uniwersytet Jagielloński. Instytut Fizyki. Time-reversal symmetr y violation in heavy atoms. Jacek Bieroń. Kraków, 24 IV 2008. Parity. Chen Ning Yang. Tsung-Dao Lee. Parity violation. parity reversal. Parity. Chen Ning Yang. Tsung-Dao Lee.

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Uniwersytet Jagielloński

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  1. Zakład Optyki Atomowej Uniwersytet Jagielloński Instytut Fizyki Time-reversal symmetry violationin heavy atoms Jacek Bieroń Kraków, 24 IV 2008

  2. Parity Chen Ning Yang Tsung-Dao Lee

  3. Parity violation parity reversal

  4. Parity Chen Ning Yang Tsung-Dao Lee

  5. a comment on (non)equivalenceof mirror and parity transformations

  6. Parity violation Chien-Shiung Wu

  7. Charge conjugation • C operation - interchange of particle with its antiparticle. • C symmetry in classical physics - invariance of Maxwell’s equations under change in sign of the charge, electric and magnetic fields. • C symmetry in particle physics - the same laws for a set of particles and their antiparticles: collisions between electrons and protons are described in the same way as collisions between positrons and antiprotons. The symmetry also applies for neutral particles. • Cy = ± y: even or odd symmetry. • Example: particle decay into two photons, for example p o 2g, by the electromagnetic force. Photon is odd under C symmetry; two photon state gives a product (-1)2 and is even. So, if symmetry is exact, then 3 photon decay is forbidden. In fact it has not been observed. • C symmetry holds in strong and electromagnetic interactions.

  8. C-symmetry violation • C invariance was violated in weak interactions because parity was violated, if CP symmetry was assumed to be preserved. • Under C operation left-handed neutrinos should transform into left-handed antineutrino, which was not found in nature. However, the combined CP operation transforms left-handed neutrino into right-handed antineutrino, which does exist.

  9. CP and Time-reversal symmetry • CP invariance was violated in neutral kaon system. • T operation - connects a process with a reversed process obtained by running backwards in time, i.e. reverses the directions of motion of all components of the system. • T symmetry: "initial state final state" can be converted to "final state initial state" by reversing the directions of motion of all particles.

  10. CPT theorem • Define product symmetries, like CP (parity and charge conjugation)  a system of antiparticles in the reverse-handed coordinate system symmetry • Combined CPT symmetry is absolutely exact: for any process, • its mirror image with antiparticles and time reversed • should look exactly as the original CPT theorem • If any one individual (or pair) of the symmetries is broken, there must be a compensating asymmetry in the remaining operation(s) to ensure exact symmetry under CPT operation • CPT symmetry was checked through the possible difference in masses, lifetimes, electric charges and magnetic moments of particle vs antiparticle and was confirmed experimentallywith 10-19accuracy(relative difference in masses)

  11. „Proof” of CPT y y rotation reflection x x C P T

  12. Howto observeTime Reversal Violation • Compare cross sections of a scattering process [running in ‘real’ time]and ‘time-reversed’ scattering process [running in ‘reversed’ time] 2. Detect an Electric Dipole Momentof an elementary particle

  13. Time Reversal Violationin atoms…………enhancement mechanismsofElectric Dipole Momentsin atoms

  14. Schiff Theorem - introduced by Ramsey and Purcell • A neutral system composed of charged objects re-arranges in an external electric field such that the net force on it cancels on average. • This may give rise to • significant shielding of the field at the location of the particle of interest • (strong) enhancement of the EDM effect • “Schiff corrections” - need for theoretical support

  15. Schiff theorem violation mechanisms: magnetic shielding volume shielding T-odd atomic beauty contest: heavy close levels of opposite parity deformed nucleus

  16. Role of atomic theory hyperfine structure magnetic dipole electric quadrupole …

  17. Enhancement of electron EDM in paramagnetic atoms opposite parity states mixed by EDM

  18. Enhancement of nuclear EDM in diamagnetic atoms P,T-odd interactions E Schiff moment MQM E octupole atomic enhancement factor

  19. Schiff moment Schiff x K opposite parity states mixed by EDM and the winner is …

  20. so, what do we know about radium ?

  21. 7s7p 7s rate in

  22. 7s6d 7s rate in

  23. 7s7p 7s rate in [PRL 98 (2007) 093001]

  24. Co-Producers (in alphabetical order) Jacek Bieroń Uniwersytet Jagielloński (300-400) Charlotte Froese Fischer Vanderbilt University (38) & NIST Stephan Fritzsche GSI Gediminas Gaigalas Vilniaus Universitetas Ian Grant University of Oxford (9) Paul Indelicato l’Université Paris VI (41) & ENS Per Jönsson Malmö Högskola T-foils = thanks to Klaus Jungmann & Hans Wilschut (KVI) YbF foils = thanks to Ed Hinds (University of Sussex) T-foils & YbF foils = conditions of use

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