35 research outputs found
Recoil Correction to Hydrogen Energy Levels: A Revision
Recent calculations of the order (Z\alpha)^4(m/M)Ry pure recoil correction to
hydrogen energy levels are critically revised. The origins of errors made in
the previous works are elucidated. In the framework of a successive approach,
we obtain the new result for the correction to S levels. It amounts to -16.4
kHz in the ground state and -1.9 kHz in the 2S state.Comment: 15 pages, Latex, no figure
Energy corrections of order mc2α6lnα in helium
Quantum-electrodynamic corrections of O(mc2α6lnα) to the electron-electron interaction in helium are evaluated for several states. The additional energy shift, which is an order of α smaller than the leading Araki-Sucher terms, raises the predicted energy of the 1s2s 1S0 state by 2.49 MHz to -960 332 039.43(18) MHz relative to He+(1s). The new value significantly alters the comparison with recent high-precision experiments. © 1993 The American Physical Society
Virtual annihilation contribution to orthopositronium decay rate
Order alpha^2 contribution to the orthopositronium decay rate due to
one-photon virtual annihilation is found to be
delta Gamma = (alpha/pi)^2 (pi^2 ln(alpha) - 0.8622(9))Gamma_LO.Comment: 2 pages, no figure
Erratum: Energy corrections of order mc2α6 In α in helium (Physical Review A (1993) 48, 6 (4804)
Ionization Potential of the Helium Atom
Ground state ionization potential of the He^4 atom is evaluated to be 5 945
204 221 (42) MHz. Along with lower order contributions, this result includes
all effects of the relative orders alpha^4, alpha^3*m_e/m_alpha and
alpha^5*ln^2(alpha).Comment: 4 page
The b quark low-scale running mass from Upsilon sum rules
The b quark low-scale running mass m_kin is determined from an analysis of
the Upsilon sum rules in the next-to-next-to-leading order (NNLO). It is
demonstrated that using this mass one can significantly improve the convergence
of the perturbation series for the spectral density moments. We obtain m_kin(1
GeV) = 4.56 \pm 0.06 GeV. Using this result we derive the value of the MS-bar
mass m: m(m) = 4.20 \pm 0.1 GeV. Contrary to the low-scale running mass, the
pole mass of the b quark cannot be reliably determined from the sum rules. As a
byproduct of our study we find the NNLO analytical expression for the cross
section e+e- --> Q\bar Q of the quark antiquark pair production in the
threshold region, as well as the energy levels and the wave functions at the
origin for the ^1S_3 bound states of Q\bar Q.Comment: 22 pages, Late