相关论文: Signature of the existence of the positronium mole…

The pp -> pp gamma reaction has been studied at a beam energy of 310 MeV by detecting both final protons at the PROMICE-WASA facility and identifying the photon through the resulting missing-mass peak. The photon angular distribution in the…

We present the first evidence of excitation of the $5p_{3/2} \rightarrow 6p_{1/2}$ electric dipole-forbidden transition in atomic rubidium. The experiments were carried out in a rubidium vapor cell using Doppler-free optical-optical…

High-spin spectroscopic study of $^{202}$Po ($Z$ = 84, $N$ = 118) has been carried out using the $^{195}$Pt($^{12}$C, 5n)$^{202}$Po fusion-evaporation reaction. An extended level scheme has been proposed up to an excitation energy of…

The excitation energy of the 1/2$^-$ isomer in $^{99}$In at ${N=50}$ is measured to be 671(37) keV and the mass uncertainty of the 9/2$^+$ ground state is significantly reduced using the ISOLTRAP mass spectrometer at ISOLDE/CERN. The…

This paper presents the electron and photon energy calibration obtained with the ATLAS detector using 140 fb$^{-1}$ of LHC proton-proton collision data recorded at $\sqrt{s}=13$ TeV between 2015 and 2018. Methods for the measurement of…

Positron scattering and annihilation on noble gas atoms below the positronium formation threshold is studied ab initio using many-body theory methods. The many-body theory provides a near-complete understanding of the…

This talk gives an elementary introduction to the basic properties of positronium. Recent progress in theoretical studies of the hyperfine splitting and lifetime of the ground state is reviewed. Sensitivity of these precisely measured…

High energy (~GeV) positrons are seen within cosmic rays and observation of a narrow line at 511 keV shows that positrons are annihilating in the galaxy after slowing down to ~keV energies or less. Our state of knowledge of the origin of…

The scalar and tensor components of the electric quadrupole (E2) polarizabilities of the first two excited states of all the alkali-metal atoms are determined. To validate the calculations, we have evaluated the ground state E2…

Monte Carlo simulations of slow positron production via energetic electron interaction with a solid target have been performed. The aim of the simulations was to determine the expected slow positron beam intensity from a low energy, high…

We present a computational study of the laser-driven quantum dynamics of positronium (Ps), PsH, and PsCl at the time-dependent Hartree-Fock level of theory. To eliminate finite-basis effects and to properly capture continuum dynamics, we…

The a(1) state of PbO can be used to measure the electric dipole moment of the electron d_e. We discuss a semiempirical model for this state, which yields an estimate of the effective electric field on the valence electrons in PbO. Our…

In the positron-electron annihilation process, finite deviations from the standard calculation based on the Fermi's Golden rule are suggested in recent theoretical work. This paper describes an experimental test of the predictions of this…

We present an exceptional twin-Higgs model with the minimal symmetry structure for an exact implementation of twin parity along with custodial symmetry. Twin particles are mirrors of the Standard Model yet they carry hypercharge, while the…

Photoelectron emission from excited states of laser-dressed atomic helium is analyzed with respect to laser intensity-dependent excitation energy shifts and angular distributions. In the two-color XUV (exteme ultra\-violet) -- IR (infrared)…

We present the first observation of the bottomonium ground state eta_b(1S) in the photon energy spectrum using a sample of 109+/-1 million of Upsilon(3S) events recorded at the Upsilon(3S) energy with the BaBar detector at the PEP-II B…

Potassium-40 is a widespread isotope whose radioactivity impacts estimated geological ages spanning billions of years, nuclear structure theory, and subatomic rare-event searches - including those for dark matter and neutrinoless…

Excited states in 40Si have been established by detecting gamma-rays coincident with inelastic scattering and nucleon removal reactions on a liquid hydrogen target. The low excitation energy, 986(5) keV, of the 2+[1] state provides evidence…

Two methods based on bremsstrahlung were applied to the stable even Mo isotopes for the experimental determination of the photon strength function covering the high excitation energy range above 4 MeV with its increasing level density.…

The reactions of the low-lying metastable states of atomic phosphorus, P($^2$D) and P($^2$P), with H$_{2}$O and H$_{2}$ were studied by the pulsed laser photolysis at 248 nm of PCl$_{3}$ , combined with laser induced fluorescence detection…