Related papers: High resolution spectroscopy of muonium
The spectrum of electrons from muons decaying in an atomic bound state is significantly modified by their interaction with the nucleus. Somewhat unexpectedly, its first measurement, at the Canadian laboratory TRIUMF, differed from basic…
The MUonE experiment has been proposed to measure the differential cross section of $\mu e$ elastic scattering, by colliding the 160 GeV muons of the CERN M2 beam with atomic electrons of thin target plates. From a very precise measurement…
The muon anomalous magnetic moment is one of the most precisely measured quantities in particle physics. In a recent experiment at Brookhaven it has been measured with a remarkable 14-fold improvement of the previous CERN experiment…
The hyperfine (hf) transition rates for muonic atoms have been re-measured for select light nuclei, using neutron detectors to evaluate the time dependence of muon capture. For $^{19}$F $\Lambda$$_{h}$ = 5.6 (2) $\mu$s$^{-1}$ for the hf…
Accurate spectroscopic measurements of calculable systems provide a powerful method for testing the Standard Model and extracting fundamental constants. Recently, spectroscopic measurements of finite nuclear size effects in normal and…
High precision spectroscopy can provide a sensitive tool to test Coulomb's law on atomic length scales. This can then be used to constrain particles such as extra "hidden" photons or minicharged particles that are predicted in many…
Positronium is an ideal system for the research of the bound state QED. New precise measurement of orthopositronium decay rate has been performed with an accuracy of 150 ppm, and the result combined with the last three is 7.0401 +- 0.0007…
Quantum Electrodynamics describes electromagnetic interactions of free muons and of muon and electron in the muonium atom to very high accuracy. Contributions of other and yet unknown interactions can be investigated in precision…
A high-statistics determination of the differential cross section of elastic muon-electron scattering as a function of the transferred four-momentum squared, $d \sigma_{el}(\mu e \to \mu e)/dq^2$, has been argued to provide an effective…
Experimental searches for lepton-flavor-violating coherent muon-to-electron conversion in the field of a nucleus, have been proposed to reach the unprecedented sensitivity of 10^(-16) - 10^(-18) per stopped muon. At that level, they probe…
Study of the fusion reactions between hydrogen isotopes in muonic molecules is the first example of the accurate accounting of the nucleus charge screening by a muon in the fusion process. At LUNA installation the measurements of…
Antiprotonic helium, a neutral exotic three-body system consisting of a helium nucleus, an electron and an antiproton, is being studied at the Antiproton Decelerator of CERN by the ASAUCSA collaboration. Using laser spectroscopy of the…
In contrast to other atomic systems, in true muonium ($\mu^+\mu^-$) the leading-order $Z$ boson corrections to the hyperfine splitting are shown to be experimentally accessible in the near future. This contribution ($-109$ MHz) constitutes…
The purpose of this article is twofold. First, we attempt to give a brief overview of the different application areas of quantum electrodynamics (QED). These include fundamental physics (prediction of atomic energy levels), where the atom…
The Mu2e and COMET collaborations will search for nucleus-catalyzed muon conversion to positrons ($\mu^-\rightarrow e^+$) as a signal of lepton number violation. A key background for this search is radiative muon capture where either: 1) a…
Precision measurements in nuclear muon capture on the proton and $^3$He allow for tests of the Standard Model for the strong and electroweak interactions, complementary to those achieved in high energy experiments. The present situation and…
True muonium, the bound state of a muon and an antimuon, is a theoretically well-understood but experimentally unobserved exotic atom. Its purely leptonic nature makes it a sensitive probe for bound-state quantum electrodynamics and…
QED theory of the hyperfine splitting of the $1s$ and $2s$ state in hydrogen isotopes and helium-3 ion is considered. We develop an accurate theory of a specific difference 8E_{HFS}(2s)-E_{HFS}(1s). We take into account fourth order…
We reevaluate the hadronic contribution to the running of the QED fine structure constant \aqed at $s=M_{\rm Z}^2$. We use data from \ee\ annihilation and $\tau$ decays at low energy and at the $q\bar{q}$ thresholds, where resonances occur.…
The MuCap experiment measures the singlet rate Lambda_S of muon capture on the proton. A negative muon beam is stopped in a time projection chamber filled with ultra-pure hydrogen gas at 10 bar and room temperature. In combination with the…