Properties ofJ/ψatTc: QCD second-order Stark effect

Second-order Approximate Corrections for QCD Processes

Second Order Stark-Effect Induced Gailitis Resonances in e + Ps and p + 7Li

We present a detailed comparison between the first order Stark-effect induced Gailitis resonance in e+ + H (n = 2) and the second order Stark-effect induced resonance in e + Ps (n = 1). Common characteristics as well as differences of these resonances will be identified. These results will be used to assess the presence of Gailitis resonances in the scattering of proton on the ground state of 7...

Higher-order Stark effect on an excited helium atom

Degenerate perturbation theory is used to study dipole susceptibilities of an excited helium atom in an external electric field. The dependence of the perturbed energy of levels in atoms on fine-structure effects and on the higher-order Stark effect is investigated. Numerical results have been obtained for the (1s3p) P0 and (1s3p) P2 states of helium. The magnitude of the electric field and the...

Stark Effect

An electric field partly lifts the degeneracies of atomic energy levels. This splitting was observed by Stark [1] and explained by Schrödinger [2]. We compute the Stark effect on atomic hydrogen using perturbation theory by diagonalizing the perturbation term in the N-fold degenerate multiplet of states with principal quantum number N . We exploit the symmetries of this problem to simplify the ...

Second Order QCD Corrections to Γ ( t → Wb )

Corrections of O(α 2 s) to the decay of the top quark into a W boson and a bottom quark are calculated. The method is based on an expansion of the top quark propa-gator for small external momentum, q, as compared to the top quark mass, M t. The physical point q 2 = M 2 t is reached through Padé approximations. The described method allows to take effects induced by a finite W boson mass into acc...