Resonance double magnetic bremsstrahlung in a strong magnetic field

The possibility of resonance double magnetic bremsstrahlung in the approximation of weakly excited electron states in a strong external magnetic field is analyzed. The differential probability of this process in the Breit-Wigner form is obtained. The probability of double magnetic bremsstrahlung (second-order process of perturbation theory) is compared with the probability of magnetic bremsstrahlung (first-order process of perturbation theory).     

On the confinement of quarks and vector gluons in a superconducting phase

Within a simple model of a self-interacting quark field an attempt is described to introduce diquarks a priori by spontaneous breaking of gauge invariance much in the same way as electron pairs are incorporated by the nonrelativistic BCS theory of superconductivity. This is done because baryons can be regarded as a quark-diquark system. It is shown that quarks with a mass smaller than the invariant mass gap will find it energetically unfavourable to enter a superconducting region. By referring to the Boson transformation method it is argued that bag, respectively, vortex type solutions exist. The quark-quark pairing in the groundstate induces a spontaneous breaking of Lorentz isotropy which, by the Goldstone theorem, leads to automatically confined (abelian) vector gluons of zero mass in the skin region of the hadron. A large anomalous spin-spin coupling among the valence quarks, as required by the π-? mass difference, is likely to be present. It is pointed out that the skin region of mesons and baryons may have a different structure. Solutions where the quark moves freely inside a confined region correspond to the possibility of having a space dependent mass gap.     

Exact solutions of the equations of motions of quarks in a non-Abelian field of a flat color wave

Exact solutions of the equations of motion of quarks in a non-Abelian field of a flat color wave of a spectral configuration are obtained. The gauge field of the wave takes values from the SU(2) group and is an exact solution of the Yang-Mills equations.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 76–78, December, 1986.     

The ridge as a shadowing effect in hydrodynamics

The aim of this work is to clarify the origin of the in-plane/out-of-plane effect, in the two-particle correlation function, computed with the NexSPheRIO code, in Au + Au collisions at 200 AGeV. We show that such an effect can be understood in terms of the shadowing effect caused by a peripheral high-energydensity tube.     

The recoil effect in a strong electromagnetic field

The recoil effect in a strong resonance field of a standing electromagnetic wave has been studied. In order to find the response to the external field (the induced dipole momentum) it is necessary to take into account the variations in the motion of the atoms in this field: the response and the energy spectrum of the atoms are determined from the system of wave equations for the multi-level atoms. The problem of a weak signal absorption in the presence of a strong standing wave which is in resonance with the adjacent transition, is solved. In this case the contour of the absorption line is shown to diverge into two wide bands, their width being proportional to the strong field amplitude. The contribution of continuous and discrete states of the atoms in a standing wave field has been found.     

Results of searches for extra spatial dimensions in the CMS experiment at the LHC

An overview of basic results of the CMS experiment that concern searches for signals from extra spatial dimensions in the course of the first run of the Large Hadron Collider (LHC) at the c.m. proton–proton collision energies of 00000 and 8 TeV is given.     

Study of electron bremsstrahlung in strong Coulomb fields at the ESR storage ring

Electron bremsstrahlung has been investigated for collisions of 223.2 MeV/amu He-like uranium ions with N₂ and Ar gaseous targets. The doubly differential cross-sections for bremsstrahlung are compared to the predictions of relativistic first order Born calculations (Bethe-Heitler formula with Elwert correction factor) and to the calculations based on the exact wavefunctions for electrons moving in the external point-Coulomb potential of the projectile. Whereas the “exact” IPA calculations give an improved agreement with experimental data, as compared to the Bethe-Heitler theory, in particular at the end-point region of the bremsstrahlung spectra, discrepancies still remain at lower photon energies. This revised version was published online in July 2006 with corrections to the Cover Date.     

Probing the medium-induced energy loss of bottom quarks by dimuon production in heavy ion collisions at LHC

The potential of coming experiments on the Large Hadron Collider (LHC) to observe the rescattering and energy loss of heavy quarks in the dense matter created in heavy ion collisions is discussed. We analyze the sensitivity of high-mass pairs from semileptonic decays and secondary 's from single B decays to the medium-induced bottom quark energy loss. Received: 18 December 2000 / Revised version: 17 May 2001 / Published online: 6 July 2001     

Vacuum in a strong magnetic field as a hyperbolic metamaterial

As demonstrated by Chernodub, vacuum in a strong magnetic field behaves as Abrikosov vortex lattice in a type-II superconductor. We investigate electromagnetic behavior of vacuum in this state and demonstrate that vacuum behaves as a hyperbolic metamaterial. If the magnetic field is constant, low frequency extraordinary photons experience this medium as a (3+1) Minkowski spacetime in which the role of time is played by the spatial z coordinate. Variations of the magnetic field curve this spacetime, and may lead to formation of "electromagnetic black holes." Since hyperbolic metamaterials behave as diffractionless "perfect lenses," and large enough magnetic fields probably existed in the early Universe, the demonstrated hyperbolic behavior of early vacuum may have imprints in the large scale structure of the present-day Universe.     

Study of the Standard Model Higgs Boson in the ATLAS and CMS Experiments at the LHC

Physics of Atomic Nuclei - Recent results on Higgs boson production and decays in the ATLAS and CMS experiments at the LHC are reviewed. These results are based on data accumulated from 2015 to...     

The effect of strong electric field on lattice relaxation at metal surface

The density functional formalism is used to study changes in the lattice relaxation induced by negative electric field at closed packed faces of Li, Na, Al and Cu. Due to the simple form of the parametrized density profile assumed, the calculation is performed analytically. For the typical fields applied in field emission the calculated relaxations can be increased up to 21% due to the electric field, depending on metal and crystallographic plane considered.     

Coulomb corrections to bremsstrahlung in the electric field of a heavy atom at high energies

We consider the differential and partially integrated cross sections for bremsstrahlung from high-energy electrons in an atomic field, with this field taken into account exactly. We use the semiclassical electron Green function and wavefunctions in an external electric field. It is shown that the Coulomb corrections to the differential cross section are very susceptible to screening. Nevertheless, the Coulomb corrections to the cross section summed over the final-electron states are independent of screening in the leading approximation in the small parameter 1/mr _scr (r _scr is the screening radius and m is the electron mass, ? = c = 1). We also consider bremsstrahlung from a finite-size electron beam on a heavy nucleus. The Coulomb corrections to the differential probability are also very susceptible to the beam shape, while the corrections to the probability integrated over momentum transfer are independent of it, apart from the trivial factor, which is the electron-beam density at zero impact parameter. For the Coulomb corrections to the bremsstrahlung spectrum, the next-to-leading terms with respect to the parameters mε (ε is the electron energy) and 1/mr _scr are obtained.     

强磁场中超冷费米气体的相对论效应

由单粒子的弱相对论能谱及泊松公式,导出强磁场中费米气体的热力学势函数.在此基础上,运用热力学关系求解低温条件下系统的统计特征量的解析式,分析相对论效应对统计性质的影响机理.研究表明,磁场愈强,相对论效应愈明显.相对论效应引发的单调项与相应的振荡项的振幅相比,对总能,单调项远大于振幅;对化学势及磁矩,单调项与振幅几乎同一量级. 关键词： 强磁场 费米气体 相对论效应     

Antipolarization effect in quantum wells in a strong external alternating field

It is shown that when a strong ac electric field acts on an electron in a double quantum well, the dipole moment is an almost periodic function of the dc voltage applied to the structure. An antipolarization effect — the structure is polarized in a direction opposite to the external field — appears during one half of the period. Pis’ma Zh. éksp. Teor. Fiz. 70, No. 6, 386–391 (25 September 1999)     

Threshold resummation for the production of a color sextet (antitriplet) scalar at the LHC

This paper is devoted to the study of warm inflation using vector fields in the background of a locally rotationally symmetric Bianchi type I model of the universe. We formulate the field equations, and slow-roll and perturbation parameters (scalar and tensor power spectra as well as their spectral indices) in the slow-roll approximation. We evaluate all these parameters in terms of the directional Hubble parameter during the intermediate and logamediate inflationary regimes by taking the dissipation factor as a function of the scalar field as well as a constant. In each case, we calculate the observational parameter of interest, i.e., the tensor–scalar ratio in terms of the inflaton. The graphical behavior of these parameters shows that the anisotropic model is also compatible with WMAP7 and the Planck observational data.     

Faraday effect in alkali-metal vapors in a strong bichromatic field of laser light

Results of a numerical study of the Faraday effect arising upon propagation of the light beams with the frequencies ω _L1 (resonant to the nS _1/2-nP _{1/2, 3/2} transitions) and ω _L2 (resonant to the nP _{1/2, 3/2}-(n+2)S _1/2 transitions) through alkali-metal vapors are presented. Characteristics of the magneto-optical rotation spectra at each of the frequencies are strongly affected by the second intense radiation field resonant to the adjacent transition. When the atoms interact with two strong light waves, resonant to adjacent transitions, and with a magnetic field, the shape of the Faraday rotation spectra depends on the energy shifts of the atomic states that arise due to the dynamic Stark effect and the Zeeman effect (the Paschen-Back or an intermediate-type effect), as well as due to the difference of populations of these states caused by the interaction of the atoms with the fields. The results obtained show that in the frequency selection method, based on the resonance Faraday effect, the frequency of the generated narrow-band beam can be tuned by the intensity of the strong wave, resonant to the transition between the excited states.     

The Aharonov-Bohm effect as a manifestation of the Zeeman interaction

We prove that there exists an infinite-dimensional Poisson subalgebra in a C (²ⁿ ) invariant with respect to the Moyal bracket but not rigid, i.e., admitting nontrivial deformations.