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. C : even or odd symmetry. Example: particle decay into two photons, for example o 2 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.
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.
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.
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 experimentally with 10 -19 accuracy (relative difference in masses)
Howto observe Time Reversal Violation 2. Detect an Electric Dipole Moment of an elementary particle 1.Compare cross sections of a scattering process [running in ‘real’ time] and ‘time-reversed’ scattering process [running in ‘reversed’ time]
Time Reversal Violation in atoms ………… enhancement mechanisms of Electric Dipole Moments in atoms
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
Schiff theorem violation mechanisms: magnetic shielding volume shielding T-odd atomic beauty contest: heavy close levels of opposite parity deformed nucleus
Role of atomic theory hyperfine structure magnetic dipole electric quadrupole …
Enhancement of electron EDM in paramagnetic atoms opposite parity states mixed by EDM
Schiff moment MQM E octupole E P,T-odd interactions atomic enhancement factor Enhancement of nuclear EDM in diamagnetic atoms
Schiff moment opposite parity states mixed by EDM Schiff x K and the winner is …
Co-Producers (in alphabetical order) Jacek Bieroń Uniwersytet Jagielloński (300-400) Charlotte Froese Fischer Vanderbilt University (38) & NIST Ian Grant University of Oxford (9) Per Jönsson Malmö Högskola Paul Indelicato l’Université Paris VI (41) & ENS Stephan Fritzsche GSI T-foils = thanks to Klaus Jungmann & Hans Wilschut (KVI) YbF foils = thanks to Ed Hinds (University of Sussex) Gediminas Gaigalas Vilniaus Universitetas T-foils & YbF foils = conditions of use