105 research outputs found
Relativistic corrections to the pair Bc-meson production in e+e− annihilation
No full textAbstractRelativistic corrections to the pair Bc-meson production in e+e−-annihilation are calculated. We investigate a production of pair pseudoscalar, vector and pseudoscalar+vector Bc-mesons in the leading order perturbative quantum chromodynamics and relativistic quark model. Relativistic expressions of the pair production cross sections are obtained. Their numerical evaluation shows that relativistic effects in the production amplitudes and bound state wave functions three times reduce nonrelativistic results at the center-of-mass energy s=22 GeV
Hyperfine splitting of P-states in light muonic ions
No full textWe calculate hyperfine structure intervals for P–states in muonic ions of lithium, beryllium and boron. To construct the particle interaction operator in momentum space we use the tensor method ofprojection operators on states with definite quantum numbers of total atomic momentum F and total muonmomentum j. We take into account vacuum polarization, relativistic, quadruple and structure corrections of orders α4, α5 and α6. The obtained numerical values of hyperfine splittings can be used for a comparison with future experimental data
Hyperfine structure of S-states of muonic tritium
No full textOn the basis of quasipotential method in quantum electrodynamics we carry out a precise calculation of hyperfine splitting of S-states in muonic tritium. The one-loop and two-loop vacuum polarization corrections, relativistic effects, nuclear structure corrections in first and second orders of perturbation theory are taken into account. The contributions to hyperfine structure are obtained in integral form and calculated analytically and numerically. Obtained results for hyperfine splitting can be used for a comparison with future experimental data of CREMA collaboration
Hyperfine structure of S-states of muonic tritium
No full textOn the basis of quasipotential method in quantum electrodynamics we carry out a precise calculation of hyperfine splitting of S-states in muonic tritium. The one-loop and two-loop vacuum polarization corrections, relativistic effects, nuclear structure corrections in first and second orders of perturbation theory are taken into account. The contributions to hyperfine structure are obtained in integral form and calculated analytically and numerically. Obtained results for hyperfine splitting can be used for a comparison with future experimental data of CREMA collaboration
COOPERATIVE EFFECTS IN OPTICAL AND ESR SPECTROSCOPY OF NITROGEN ATOMS ISOLATED BY SOLIDIFICATED HELIUM
No full text1. E.B. Gordon, V.V. Khmelenko, A.A. Pelmenev, E.A. Popov and O.P. Pugachev, Chem. Phys. Lett. 155(3), 301-304 (1989). 2. R.E. Boltnev, E.B. Gordon, V.V. Khmelenko, A.A. Pelmenev, I.N. Kusliniskaya, M.V. Martynenko, E.A. Popov and A.V. Shestakov, Chem. Phys. 189(2), 367-382 (1994). 3. R.E. Boltnev, E.B. Gordon, V.V. Khmelenko, M.B. Martynenko, A.A. Pelmenev, E.A. Popov and A.F. Shestakov, J. Chim. Phys. 92(2), 362-383 (1995).Author Institution: Institute for Energy Problems of Chemical Physics (branch)The heavy guest particles embedded to superfluid helium can cause its . The so-called Impurity Helium Solid Phase (IHSP) being stable then up T = 7K shows the regular arrangement of the impurities with their reliable isolation by helium atoms. The feasibility of previously excited species capture to IHSP may be achieved. So metastable N(D) atoms display extremely long-lived, more than s, luminescence. Their radiative decay turns out to be caused solely by excimer-like state formation with accidentally neighbouring heavy . That was proved for N(D)-Rg pairs (Rg = Ne, Ar, Kr, Xe) by both spectra shapes and emission lifetimes observed. For N(D)- state the comparison of atomic and rovibronic spectra evidences their excimer nature as . The distances between neighbour N atoms in IHSP, 1 mm, are small enough for cooperative bulk magnetic effects appearances. ESR experiments with N(S) atoms show the effects of either magnetic alignment or spin-exchange narrowing
LOW TEMPERATURE INTRAMOLECULAR ENERGY TRANSFER IN GAS PHASE EVIDENCED BY LUMINESCENCE OF , AND CN.
No full text1. E.B. Gordon, A.A.Pelmenev, O.F. Pugachev and V.V.Khmelenko, Chem. Phys. 61(1,2), 35-41, 1981. 2. E.B. Gordon, M.V. Martynenko, A.A. Pelmenev, O.F. Pugachev and V.V. Khmelenko, Khimicheskay Fizika, 13(3), 15-28, 1994, (in Russian).Author Institution: Institute for Energy Problems of Chemical Physics, 1142432, Chernogolovka, Moscow Region, Russia.Gas phase luminescence spectra of N_{2} (1^{+}-system), (N^{+}}_{2} (1^{+}-system), and CN (Red system) in the temperature range 180K - 20K have been studied in the frame of original experimental approach [1] consisting in injection of helium gas jet containing the exposed to HF discharge admixtures under investigation into the cryostat with superfluid helium . At low temperatures together with strong suppression of rotational structure the dramatic changes in the vibronic bands intensity (some bands almost completely disappear) are observed [2]. For all vibrational levels from which emission is temperature sensitive there are quasiresonant vibrational levels belonging to another electronic states of the same species. So the effect has been explained by effective energy transfer between the electronic states induced by collisions with cold helium atoms . The emission bands intensity is determined by mutual disposition of the interacting levels. Its decrease or increase depend on whether exothermic or endothermic, respectively, transition from emitting level to neighboring one. Observed phenomena provide new opportunities for accurate testing the mutual disposition of different electronic states in diatomics as well as for study of intersystem collisional induced processes
Radiative nonrecoil nuclear finite size corrections of order α ( Zα ) 5 to the Lamb shift in light muonic atoms
No full textThe sigma-meson exchange contribution to the muonic hydrogen Lamb shift
No full textThe sigma(ξ)meson exchange contribution to the potential of the muon-proton interactionin muonichydrogen inducedbythe ξ-meson coupling to two photons is estimated. The transition form factor ξ → γγ is deduced from the quark model and experimental data on the decay widths Γσγγ. It is shown that scalar meson exchange contribution to the Lamb shift in muonic hydrogen, △ELs(2P−2S ),is rather large and relevant for a comparison with coming precise experimental data
The LbL contribution to the muon g-2 from the axial-vector mesons exchanges within the nonlocal quark model
No full textThe light-by-light contribution from the axial-vector (AV) mesons exchanges to the muon anomalous magnetic moment is estimated in the framework of the nonlocal chiral quark model. The preliminary answer for contributions from a1 and f1 mesons to (g − 2)µ is 0.34 · 10−11 and does not support the Melnikov-Vainshtein estimate 2.2 · 10−11
Radiative nonrecoil nuclear finite size corrections of order α(Zα)5 to the Lamb shift in light muonic atoms
No full textOn the basis of quasipotential method in quantum electrodynamics we calculate nuclear finite size radiative corrections of order α(Zα)5 to the Lamb shift in muonic hydrogen and helium. To construct the interaction potential of particles, which gives the necessary contributions to the energy spectrum, we use the method of projection operators to states with a definite spin. Separate analytic expressions for the contributions of the muon self-energy, the muon vertex operator and the amplitude with spanning photon are obtained. We present also numerical results for these contributions using modern experimental data on the electromagnetic form factors of light nuclei. Keywords: Lamb shift, Muonic atoms, Quantum electrodynamic
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