arXiv subjects

Klaus P. Jungmann

Publications and source records attributed to Klaus P. Jungmann.

9 recordsLinked to original sources

arXiv2016

Precision Muonium Spectroscopy

The muonium atom is the purely leptonic bound state of a positive muon and an electron. It has a lifetime of 2.2 $μ$s. The absence of any known internal structure provides for precision experiments to test fundamental physics theories and to determine accurate values of fundamental constants. In particular groun dstate hyperfine structure transitions can be measured by microwave spectroscopy to deliver the muon magnetic moment. The frequency of the 1s-2s transition in the hydrogen-like atom can be determined with laser spectroscopy to obtain the muon mass. With such measurements fundamental physical interactions, in particular Quantum Electrodynamics, can also be tested at highest precision. The results are important input parameters for experiments on the muon magnetic anomaly. The simplicity of the atom enables further precise experiments, such as a search for muonium-antimuonium conversion for testing charged lepton number conservation and searches for possible antigravity of muons and dark matter.

hep-ex↗

arXiv2005

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.

hep-ex↗

arXiv2005

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.

nucl-ex↗

arXiv2005

Fundamental Symmetries and Interactions

In Nuclear Physics numerous possibilities exist to investigate fundamental symmetries and interactions. In particular, the precise measurements of properties of fundamental fermions, searches for new interactions in $β$-decays, and violations of discrete symmeties offer possibilities to search for physics beyond Standard Theory. Precise measurements of fundamental constants can be carried out. Low energy experiments allow to probe New Physics at mass scales far beyond the reach of present accelerators or such planned for the future and at which predicted new particles could be produced directly.

nucl-ex↗

arXiv2005

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.

physics.atom-ph↗

arXiv2004

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.

nucl-ex↗

arXiv2002

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.

nucl-ex↗

arXiv1998

Lepton Flavour Violation Experiments -- Some Recent Developments

Dedicated experiments searching for lepton flavour violation can be performed very sensitively using K-decays and $μ$-decays as well as neutrinoless double $β$-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.

hep-ex↗

arXiv1998

Muonium

The energy levels of the muonium ($μ^+ e^-$) atom, which consists of two ''point-like'' leptonic particles, can be calculated to very high accuracy in the framework of bound state Quantum Electrodynamics (QED), since there are no complications due to internal nuclear structure and size which is the case for all atoms and ions of natural isotopes including atomic hydrogen. The ground state hyperfine splitting and the 1s-2s energy interval can provide both tests of QED theory and determinations of fundamental constants like the muon mass $m_μ$ and the fine structure constant $α$. The excellent understanding of the electromagnetic binding in the muonium atom allows in particular testing fundamental physical laws like lepton number conservation in searches for muonium to antimuonium conversion and probing the nature of the muon as a heavy leptonic object. New measurements on the ground state hyperfine splitting and the 1s-2s transition are discussed.

physics.atom-ph↗