Spatial structure of the modified Coulomb potential in a superstrong magnetic field

The modification of the Coulomb potential due to the enhancement of loop corrections in a superstrong magnetic field is studied numerically. We calculate the modified potential with high precision and obtain the pattern of equipotential lines. The results confirm the general features known from previous studies, but we emphasize some differences in potential structure that can be important for problems with spatially distributed charges.     

Radiative corrections to the Coulomb energy levels and emission of a hydrogen-like atom in a superstrong magnetic field

The probability and intensity of hydrogen-like atom emission in strong magnetic field В >> Z ^2α2 B ₀, α = e ²/cħ = 1/137, and B ₀ = m ² c ³ /eħ = 4.41⋅10¹³ G is calculated. The role of electron-positron vacuum polarization is discussed.     

Nonlinear electrodynamics in a superstrong magnetic field

Using a Feynman technique in a two-dimensional space we have calculated an electron propagator and a photon polarization tensor in a superstrong magnetic field $\text{B ? B}{}_{\mathrm{<mtext>0</mtext>}}\text{=}\text{m}{}^{\mathrm{<mtext>2</mtext>}}\text{e}\text{=}\text{4.41 × 10}{}^{13}$ G. Some applications are briefly discussed.     

The hydrogen atom in a superstrong magnetic field

A new method for energy-level calculations of the H-atom in a superstrong magnetic field is proposed. The method is based on perturbation theory. The finite-difference technique is used to solve the resulting equations.     

Two-loop quantum corrections to the soliton mass in two-dimensional scalar field theories

We study higher-order corrections to the soliton mass in two-dimensional scalar field theories.We show that the second quantum correction (two-loop graphs) to the soliton mass (M_S) is finite provided one orders correctly the non-commuting operators in the effective hamiltonian. That is, the vacuum sector UV counterterm suffices to eliminate the ultraviolet and infinite volume divergences of the one-soliton sector.We evaluate explicitly the finite part of the second quantum correction to M_S in the sine-Gordon model. We find that the ratio of the soliton mass to the meson mass is the same in our perturbative calculation, as in the semiclassical one by Dashen, Hasslacher and Neveu, up to two-loop contributions.     

The Zeldovich effect in a superstrong magnetic field

It follows from the analysis of the precision numerical calculations of the energy spectrum of a hydrogen atom in a static magnetic field that the Zeldovich effect (rearrangement of the atomic spectrum) in the spectrum of atomic levels is observed at superstrong magnetic fields B≥5×10₁₁ G. Magnetic fields of such strengths are reached in neutron stars and magnetic white dwarfs. We established a lower bound B_min for the fields required for this effect to occur.     

Two-loop corrections to Bhabha scattering

The two-loop radiative photonic corrections to Bhabha scattering are computed in the leading order of the small electron mass expansion up to the nonlogarithmic term. After including the soft photon bremsstrahlung, we obtain the infrared-finite result for the differential cross section, which can directly be applied to a precise luminosity determination of the present and future e+ e- colliders.     

Quantum transitions of relativistic electrons in a superstrong magnetic field

The probability of emission of a hard γ-quantum in relativistic electron transitions to the ground (or near it) level in a magnetic field H ～ H₀ = m²c³/e₀? = 4.41 × 10¹³G is obtained. For the inverse transitions from these levels the cross-section of electron photoexitation is calculated.     

Relativistic theory of a hydrogen atom in a superstrong magnetic field

The Dirac equation for a hydrogen atom in a static, uniform magnetic field is transformed by a modified FWT transformation into a mixed form; relativistic for perpendicular motion and semi-relativistic for parallel motion. In this way the adiabatic approximation can easily be obtained.     

Two-loop QCD corrections to the longitudinal structure function

We calculate the fourth-order corrections to the longitudinal Wilson coefficient in deep inelastic scattering (for the non-singlet case). We use off-mass-shell states to control collinear singularities. A table of numerical results is presented for different numbers of quark flavours, and from these results we obtain the total next-to-leading order contributions to the moments of the longitudinal structure function.     

Two-loop electroweak corrections to lepton magnetic dipole moments in the littlest Higgs model with T-parity

Little Higgs models with T-parity predict the existence of the new sources of flavor-violating interactions between SM fermions and mirror fermions. We analyze corrections to the anomalous magnetic dipole moments of leptons from Bar-Zee-type diagrams in the LHT model. We find that the contributions of the LHT model are not sensitive to the new flavor mixing matrix and the value is of the order of 10⁻¹¹.     

A hydrogen atom in a superstrong magnetic field and the Zeldovich effect

We consider the problem of a hydrogen atom in a superstrong magnetic field, B? B _a =2.35×10⁹ G. The analytical formulas that describe the energy spectrum of this atom are derived for states with various quantum numbers n_ρ and m. A comparison with available calculations shows their high accuracy for B?B _a . We note that the derived formulas point to a manifestation of the Zeldovich effect, i.e., a rearrangement of the atomic spectrum under the influence of strong short-range Coulomb potential distortion. We discuss the relativistic corrections to level energies, which increase in importance with magnetic field and become significant for B?10¹⁴ G. We suggest the parameters in terms of which the Zeldovich effect has the simplest form. Analysis of our precision numerical calculations of the energy spectrum for a hydrogen atom in a constant magnetic field indicates that the Zeldovich effect is observed in the spectrum of atomic levels for superstrong fields, B?5×10¹¹ G. Magnetic fields of such strength exist in neutron stars and, possibly, in magnetic white dwarfs. We set lower limits for the fields B_min required for the manifestation of this effect. We discuss some of the properties of atomic states in a superstrong magnetic field, including their mean radii and quadrupole moments. We calculated the probabilities of electric dipole transitions between odd atomic levels and a deep ground level.     

Two-loop QCD corrections to top quark width

We present O(α_s²) corrections to the decay t → bW in the limit of a very large top quark mass, m_t ⪢ m_W. We find that the O(α_s²) effects decrease the top quark decay width Γ_t by about 2%: Γ_t = Γ₀ (1 − 0.8α_t (m_t) − 1.7α_s²). The complete corrections are smaller by about 24% than their estimate based on the BLM effects O(α_s²). We explain how to compute a new type of diagrams which contribute to Γ(t → bW) at the O(α_s²) level.     

Two-loop SUSY QCD corrections to the chargino masses in the MSSM

We have calculated the two-loop strong interaction corrections to the chargino pole masses in the scheme in the minimal supersymmetric standard model with complex parameters. We have performed a detailed numerical analysis for a particular point in the parameter space and found corrections of a few tenths of a percent. We provide a computer program that calculates chargino and neutralino masses with complex parameters up to .     

Energy losses of a neutron star due to inverse muon decay in the superstrong magnetic field

The emission of a pair of neutrinos by a charged lepton under the influence of a strong magnetic field is examined. The expression found in general form for the probability of the process l l'vV in the strong magnetic field of a neutron star is used to evaluate the contribution of inverse muon decaye vV to the energy losses of the neutron star. The conditions under which this contribution to the energy losses of a neutron star may compete with that due to neutrino pair emission in the processe evV are discussed.Lomonosov State University, Moscow. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 39–44, July, 1995.