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 ($\bar{p}$'s) and bound two- and three-body systems such as antihydrogen ($\bar{{\rm H}}=\bar{p}e^-$), the antprotonic helium ion (He$^{++} \bar{p}$)$^+$ and the antiprotonic atomcule (He$^{++} \bar{p}e^-$) . The trapping of a single $\bar{p}$ in a Penning trap, the formation and precise studies of antiprotonic helium ions and atoms and recently the production of $\bar{{\rm H}}$ have been among the pioneering experiments. They have led already to precise values for $\bar{p}$ 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

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

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

Lepton Flavour Violation Experiments -- Some Recent Developments

Dedicated experiments searching for lepton flavour violation can be performed very sensitively using K-decays and $\mu$-decays as well as neutrinoless double $\beta$-decay and muonium to antimuonium conversion. Although there is no confirmed signal reported yet, stringent limits for parameters in speculative extensions to the standard model can be set. Some models could recently be ruled out.Comment: submitted to Proceedings of 1st Tropical Workshop in Particle Phyics and Cosmolog

Some Aspects of Fundamental Symmetries and Interactions

The known fundamental symmetries and interactions are well described by the Standard Model. Features of this powerful theory, which are described but not deeper explained, are addressed in a variety of speculative models. Experimental tests of the predictions in such approaches can be either through direct observations at the highest possible accelerator energies or through precision measurements in which small deviations from calculated values within the Standard Model are searched for. Antiproton physics renders a number of possibilities to search for new physics.Comment: Invited talk, International Conference on Low Energy Antiproton Physics 05, Bonn, Germany, May 16-22, 200

Flat-top TIRF illumination boosts DNA-PAINT imaging and quantification

Super-resolution (SR) techniques have extended the optical resolution down to a few nanometers. However, quantitative treatment of SR data remains challenging due to its complex dependence on a manifold of experimental parameters. Among the different SR variants, DNA-PAINT is relatively straightforward to implement, since it achieves the necessary 'blinking' without the use of rather complex optical or chemical activation schemes. However, it still suffers from image and quantification artifacts caused by inhomogeneous optical excitation. Here we demonstrate that several experimental challenges can be alleviated by introducing a segment-wise analysis approach and ultimately overcome by implementing a flat-top illumination profile for TIRF microscopy using a commercially-available beam-shaping device. The improvements with regards to homogeneous spatial resolution and precise kinetic information over the whole field-of-view were quantitatively assayed using DNA origami and cell samples. Our findings open the door to high-throughput DNA-PAINT studies with thus far unprecedented accuracy for quantitative data interpretation

Dual Magnetic Separator for TRIμ\muP

The TRI$\mu$P facility, under construction at KVI, requires the production and separation of short-lived and rare isotopes. Direct reactions, fragmentation and fusion-evaporation reactions in normal and inverse kinematics are foreseen to produce nuclides of interest with a variety of heavy-ion beams from the superconducting cyclotron AGOR. For this purpose, we have designed, constructed and commissioned a versatile magnetic separator that allows efficient injection into an ion catcher, i.e., gas-filled stopper/cooler or thermal ionizer, from which a low energy radioactive beam will be extracted. The separator performance was tested with the production and clean separation of $^{21}$Na ions, where a beam purity of 99.5% could be achieved. For fusion-evaporation products, some of the features of its operation as a gas-filled recoil separator were tested.Comment: accepted by Nucl.Instr. Meth., final versio