Search results for "Exotic atom"
showing 10 items of 40 documents
High magnetic fields for fundamental physics
2018
Various fundamental-physics experiments such as measurement of the birefringence of the vacuum, searches for ultralight dark matter (e.g., axions), and precision spectroscopy of complex systems (including exotic atoms containing antimatter constituents) are enabled by high-field magnets. We give an overview of current and future experiments and discuss the state-of-the-art DC- and pulsed-magnet technologies and prospects for future developments.
Implementation of local chiral interactions in the hyperspherical harmonics formalism
2021
With the goal of using chiral interactions at various orders to explore properties of the few-body nuclear systems, we write the recently developed local chiral interactions as spherical irreducible tensors and implement them in the hyperspherical harmonics expansion method. We devote particular attention to three-body forces at next-to-next-to leading order, which play an important role in reproducing experimental data. We check our implementation by benchmarking the ground-state properties of $^3$H, $^3$He and $^4$He against the available Monte Carlo calculations. We then confirm their order-by-order truncation error estimates and further investigate uncertainties in the charge radii obta…
The next generation of laser spectroscopy experiments using light muonic atoms
2018
Precision spectroscopy of light muonic atoms provides unique information about the atomic and nuclear structure of these systems and thus represents a way to access fundamental interactions, properties and constants. One application comprises the determination of absolute nuclear charge radii with unprecedented accuracy from measurements of the 2S - 2P Lamb shift. Here, we review recent results of nuclear charge radii extracted from muonic hydrogen and helium spectroscopy and present experiment proposals to access light muonic atoms with Z ≥ 3. In addition, our approaches towards a precise measurement of the Zemach radii in muonic hydrogen (μp) and helium (μ 3He+) are discussed. These resul…
Theory of the Lamb Shift and fine structure in muonic 4He ions and the muonic 3He– 4He Isotope Shift
2018
Abstract We provide an up to date summary of the theory contributions to the 2S → 2P Lamb shift and the fine structure of the 2P state in the muonic helium ion ( μ 4 He ) + . This summary serves as the basis for the extraction of the alpha particle charge radius from the muonic helium Lamb shift measurements at the Paul Scherrer Institute, Switzerland. Individual theory contributions needed for a charge radius extraction are compared and compiled into a consistent summary. The influence of the alpha particle charge distribution on the elastic two-photon exchange is studied to take into account possible model-dependencies of the energy levels on the electric form factor of the nucleus. We al…
The subtraction contribution to the muonic-hydrogen Lamb shift: a point for lattice QCD calculations of the polarizability effect
2020
The proton-polarizability contribution to the muonic-hydrogen Lamb shift is a major source of theoretical uncertainty in the extraction of the proton charge radius. An empirical evaluation of this effect, based on the proton structure functions, requires a systematically improvable calculation of the "subtraction function", possibly using lattice QCD. We consider a different subtraction point, with the aim of accessing the subtraction function directly in lattice calculations. A useful feature of this subtraction point is that the corresponding contribution of the structure functions to the Lamb shift is suppressed. The whole effect is dominated by the subtraction contribution, calculable o…
Zemach moments and radii of H2,3 and He3,4
2019
We present benchmark calculations of Zemach moments and radii of $^{2,3}\mathrm{H}$ and $^{3,4}\mathrm{He}$ using various few-body methods. Zemach moments are required to interpret muonic atom data measured by the CREMA collaboration at the Paul Scherrer Institute. Conversely, radii extracted from spectroscopic measurements can be compared with ab initio computations, posing stringent constraints on the nuclear model. For a given few-body method, different numerical procedures can be applied to compute these quantities. A detailed analysis of the numerical uncertainties entering the total theoretical error is presented. Uncertainties from the few-body method and the calculational procedure …
What can be learnt about nuclear polarization from a consistency analysis ofe ? cross sections and muonic X-rays for208Pb and the isotone pair209Bi/2…
1977
A joint analysis of recent electron scattering cross sections and muonic atom X-ray energies is performed for208Pb and the isotone pair209Bi/208Pb. From the compatibility of the experimental data one can learn about the nuclear polarisation correction. However, we find this information not to be as accurate as other authors claimed when we take into consideration the ambiguities in the treatment of the corrections of the higher levels.
Constraints to new physics models for the proton charge radius puzzle from the decayK+→μ++ν+e−+e+
2014
A possible explanation for the discrepancy between electronic and muonic hydrogen measurements of the proton charge radius are new, lepton-universality violating interactions. Several new couplings and particles have been suggested that account for this discrepancy. At present, these explanations are poorly constrained. Experiments such as the upcoming kaon decay experiment at JPARC may constrain or eliminate some explanations by sensitivity to the decay channel $K^+ \rightarrow \mu^+ +\nu + e^- + e^+$. We calculate the predicted contributions of the various explanations to this channel. The predicted signals, if present, should be large enough to be resolved in the experiment.
First Antiprotons in an Ion Trap
1987
Measurements of the antiproton mass[2,3,4,5] are represented in Fig. 1. All of these are deduced from measurements of the energy of x-rays radiated from highly excited exotic atoms. For example, if an antiproton is captured in a Pb atom, it can make radiative transitions from its n = 20 to n = 19 state. The antiproton is still well outside the nucleus in this case, so that nuclear effects can be neglected. The measured transition energy is essentially proportional to the reduced mass of the nucleus and hence the antiproton mass can be deduced by comparing the measured values with theoretical values, corrected for QED effects. The most accurate quoted uncertainty is 5 × 10-5 and is consisten…
The observation of vibrating pear-shapes in radon nuclei
2019
6 pags., 4 fig.s, 1 tab. -- Open Access funded by Creative Commons Atribution Licence 4.0