3,467 research outputs found
Searches for Permanent Electric Dipole Moments
A large number of well motivated searches for permanent Electric Dipole
Moments are presently under way which have a robust discovery potential. The
field has seen a number of novel ideas concerning both possible experimental
and theoretical approaches. Due to recent progress also searches in charged
particles seem to be feasible. Some aspects in this highly active field are
discussed.Comment: Review talk at Heavy Quarks and Leptons, 16.10 - 20.10.2006 Munich,
German
Low Energy Antiproton Experiments -- A Review
Low energy antiprotons offer excellent opportunities to study properties of
fundamental forces and symmetries in nature. Experiments with them can
contribute substantially to deepen our fundamental knowledge in atomic, nuclear
and particle physics. Searches for new interactions can be carried out by
studying discrete symmetries. Known interactions can be tested precisely and
fundamental constants can be extracted from accurate measurements on free
antiprotons ('s) and bound two- and three-body systems such as
antihydrogen (), the antprotonic helium ion (He) and the antiprotonic atomcule (He) . The
trapping of a single in a Penning trap, the formation and precise
studies of antiprotonic helium ions and atoms and recently the production of
have been among the pioneering experiments. They have led
already to precise values for parameters, accurate tests of bound
two- and three-body Quantum Electrodynamics (QED), tests of the CPT theorem and
a better understanding of atom formation from their constituents. Future
experiments promise more precise tests of the standard theory and have a robust
potential to discover new physics.Comment: invited talk, Workshop on Physics with Ultraslow Antiproton Beams,
Riken Wako, Japan, 14-16 March 200
Past, Present and Future of Muonium
Muonium, the atom which consists of a positive muon and an electron, has been
discovered by a team led by Vernon W. Hughes in 1960. It is in many respects
the most ideal atom available from nature. Due to the close confinement in the
bound state muonium can be used as an ideal probe of electro-weak interaction,
including particularly Quantum Electrodynamics, and to search for additional
yet unknown interactions acting on leptons. Recently completed experiments
cover the ground state hyperfine structure, the 1s-2s interval and a search for
spontaneous conversion of muonium to antimuonium. The experiments yield precise
values for the fine structure constant, the muon mass and its magnetic moment.
The results from these precision measurements have provided restrictions for a
number of theories beyond the Standard Model of particle physics. Future
precision experiments will require new and intense sources of muons.Comment: Proceedings of the Memorial Symposium in honor of Vernon Willard
Hughes, Yale, 200
Searches for Permanent Electric Dipole Moments - Some Recent Developments
Searches for permanent electric dipole moments (EDMs) of fundamental
particles render the possibility to discover New Physics beyond present
Standard Theory. New ideas for experiments have come up recently which may
allow to lower present limits substantially or even find unambiguous effects.
Such are predicted by a variety of speculative models. The identification of
potential sources for CP and T-violation will require to study several systems,
which all have different sensitivity to possible mechanisms generating EDMs.Comment: 16th International Spin Physics Symposium, Trieste, 200
Free Muons and Muonium - Some Achievements and Possibilities in Low Energy Muon Physics
Some recent precision experiments in low energy muon physics are discussed.
Spectroscopy on the muonium atom, the bound state of a positve muon and an
electron, has provided precise tests of standard theory and yielded most
precise values of important fundamental constants. A search for spontaneous
muonium to antimuonium conversion test lepton flavour conservation and yields
most stringent limits on parameters in several speculative models. The muon
magnetic anomaly may contain hints to new physics and is a relevant calibration
point for numerous models beyond standard theory. Since most precision
experiments are limited by the particle fluxes at present muon sources,
possibilities in this field are shown which will emerge at upgraded present
facilities or new accelerator complexes under construction or planning. At such
places novel techniques would be enabled
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