The 1s-2s interval has been measured in the muonium (&mgr;(+)e(-)) atom by Doppler-free two-photon pulsed laser spectroscopy. The frequency separation of the states was determined to be 2 455 528 941.0(9.8) MHz, in good agreement with quantum electrodynamics. The result may be interpreted as a measurement of the muon-electron charge ratio as -1-1.1(2.1)x10(-9). We expect significantly higher accuracy at future high flux muon sources and from cw laser technology.
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http://dx.doi.org/10.1103/PhysRevLett.84.1136 | DOI Listing |
We present a novel technique for in-vacuum cavity-enhanced UV spectroscopy that allows nearly continuous measurements over several days, minimizing mirror degradation caused by high-power UV radiation. Our method relies on pulsing of the cavity's internal power, which increases the UV intensity to maximum only for short periods when the studied atom is within the cavity mode volume while keeping the average power low to prevent mirror degradation. Additionally, this method significantly decreases laser-induced background on charged particle detectors.
View Article and Find Full Text PDFEur Phys J D At Mol Opt Phys
April 2023
Institute for Particle Physics and Astrophysics, ETH, 8093 Zurich, Switzerland.
Abstract: We present an updated value of the Muonium 1-2 transition frequency, highlighting contributions from different QED corrections as well as the large uncertainty in the Dirac contribution, stemming from the uncertainty of the electron to muon mass ratio. Improving the measurement of this spectral line would allow to extract a more accurate determination of fundamental constants, such as the electron to muon mass ratio or, combined with the Muonium hyperfine splitting, an independent value of the Rydberg constant. Furthermore, we report on the current status of the Mu-MASS experiment, which aims at measuring the Muonium 1-2 transition frequency at a uncertainty level.
View Article and Find Full Text PDFMolecules
December 2022
Drug Design and Synthesis Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse and National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Department of Health and Human Services, Rockville, MD 20852, USA.
The design of enantiopure stereoisomers of N-2-phenylcyclopropylmethyl-substituted ortho-c oxide-bridged phenylmorphans, the E and Z isomers of an N-cinnamyl moiety, and N-propyl enantiomers were based on combining the most potent oxide-bridged phenylmorphan (the ortho-c isomer) with the most potent N-substituent that we previously found with a 5-(3-hydroxy)phenylmorphan (i.e., N-2-phenylcyclopropyl methyl moieties, N-cinnamyl, and N-propyl substituents).
View Article and Find Full Text PDFACS Nano
October 2022
Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
The optoelectronic properties of two-dimensional (2D) transition metal dichalcogenide (TMDC) monolayers such as WS are largely dominated by excitons due to strong Coulomb interactions in these 2D confined monolayers, which lead to formation of Rydberg-like excitonic states below the free quasiparticle band gap. The precise knowledge of high order Rydberg excitonic states is of great importance for both fundamental understanding such as many-electron effects and device applications such as optical switching and quantum process information. Bright excitonic states could be probed by linear optical spectroscopy, while probing dark excitonic states generally requires nonlinear optical (NLO) spectroscopy.
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