Photons and static gravity

The influence of static gravitational field on frequency, wave-length and velocity of photons and on the energy levels of atoms and nuclei is considered in the most elementary way. The interconnection between these phenomena is stressed.Comment: LaTeX, 9 pages, no figures, the end of section 5 is modifie

The controllability function method

The paper is devoted to the control problem for the movement of an overhead crane with the use of a dynamic model in the form of "trolley - cargo" mechanical system and the driving force as a control parameter. To solve the system of differential equations, which describe the movement of the system taking into account constraints for the control, the controllability function method is applied. The algorithm for solving the problem is described, a program is developed as well as difficulties, which occur while implementing the method, and ways of its solution are marked. Results of constructing the control and system trajectories are also provided as an example of the program work

Testing Parity with Atomic Radiative Capture of μ−\mu^-

The next generation of "intensity frontier" facilities will bring a significant increase in the intensity of sub-relativistic beams of $\mu^-$. We show that the use of these beams in combination with thin targets of $Z\sim 30$ elements opens up the possibility of testing parity-violating interactions of muons with nuclei via direct radiative capture of muons into atomic 2S orbitals. Since atomic capture preserves longitudinal muon polarization, the measurement of the gamma ray angular asymmetry in the single photon $2S_{1/2}$-$1S_{1/2}$ transition will offer a direct test of parity. We calculate the probability of atomic radiative capture taking into account the finite size of the nucleus to show that this process can dominate over the usual muonic atom cascade, and that the as yet unobserved single photon $2S_{1/2}$-$1S_{1/2}$ transition in muonic atoms can be detected in this way using current muon facilities.Comment: To appear in PR

Do Present LEP Data Provide Evidence for Electroweak Corrections?

The Born approximation, based on $\bar\alpha \equiv\alpha (m_Z)$ instead of $\alpha$, reproduces all electroweak precision measurements within their $(1\sigma)$ accuracy. The low upper limits for the genuinely electroweak corrections constitute one of the major achievements of LEP. The astonishing smallness of these corrections results from the cancellation of a large positive contribution from the heavy top quark and large negative contributions from all other virtual particles. It is precisely the non-observation of electroweak radiative corrections that places stringent upper and lower limits on the top mass.Comment: 12 pages, preprint CERN-TH.6943/9

Theory of Z boson decays

The precision data on Z boson decays from LEP-I and SLC colliders are compared with the predictions based on the Minimal Standard Theory. The Born approximation of the theory is based on three most accurately known observables: G_mu -- the four fermion coupling constant of muon decay, m_Z -- the mass of the Z boson, and alpha(m_Z) -- the value of the running fine structure constant at the scale of m_Z. The electroweak loop corrections are expressed, in addition, in terms of the masses of higgs, m_H, of the top and bottom quarks, m_t and m_b, and of the strong interaction constant alpha_s(m_Z). The main emphasis of the review is focused on the one-electroweak-loop approximation. Two electroweak loops have been calculated in the literature only partly. Possible manifestations of new physics are briefly discussed.Comment: 80 pages, 16 figures, accepted in Reports on Progress in Physic

Baryogenesis in Cosmological Model with Superstring-Inspired E_6 Unification

We have developed a concept of parallel existence of the ordinary (O) and hidden (H) worlds with a superstring-inspired E_6 unification, broken at the early stage of the Universe into SO(10) X U(1) - in the O-world, and SU(6)' X SU(2)' - in the H-world. As a result, we have obtained in the hidden world the low energy symmetry group G'_SM X SU(2)'_\theta, instead of the Standard Model group G_SM. The additional non-Abelian SU(2)'_\theta group with massless gauge fields, "thetons", is responsible for the dark energy. We present a baryogenesis mechanism with the B-L asymmetry produced by the conversion of ordinary leptons into particles of the hidden sector.Comment: 15 pages, 2 figure

Electroweak radiative corrections in Z boson decays

Contribution to A.D.Sakharov memorial volume. A detailed review of the electroweak radiative corrections to the Z-boson decays in the framework of the Minimal Standard Modelm (MSM) is presented. After a short historical introduction we describe the optimal parametrization of the MSM, especially of the Born approximation, and derive expressions for the one-loop electroweak corrections. Finally a global fit of all relevant experimental data is performed, resulting in fitted values of the top-quark mass, m_t, and strong coupling constant /alpha_s. Allowed range for the value of the Higgs mass, m_H, is discussed. Various details of calculations are described in 16 appendices.Comment: 98 pages,21 EPS and PS figures,uses epsf.sty, separate file with the tared, compressed and uuencoded figures is awailable at http://wwwtheor.itep.ru/~vysotsky/figures.u

Multi-lepton Signatures of a Hidden Sector in Rare B Decays

We explore the sensitivity of flavour changing b -> s transitions to a (sub-)GeV hidden sector with generic couplings to the Standard Model through the Higgs, vector and axion portals. The underlying two-body decays of B mesons, B -> X_s S and B0 -> SS, where S denotes a generic new GeV-scale particle, may significantly enhance the yield of monochromatic lepton pairs in the final state via prompt decays of S to a dilepton pair. Existing measurements of the charged lepton spectrum in neutral-current semileptonic B decays provide bounds on the parameters of the light sector that are significantly more stringent than the requirements of naturalness. New search modes, such as B -> X_s + n(l+l-) and B0 -> n(l+l-) with n > 1 can provide additional sensitivity to scenarios in which both the Higgs and vector portals are active, and are accessible to (super-)B factories and hadron colliders.Comment: 12 pages, 2 figures; v2: reference added, minor correction

CP violation in unpolarized e^+ e^- to charginos at one loop level

We study CP violation in e^+ e^- to \tilde\chi_i^+\tilde\chi_j^- in the framework of the MSSM. Though the cross section of this process is CP-even at the tree level even for polarized electron-positron beams, we show that it contains a CP-odd part at the one loop order and there are CP-odd observables that can in principle be measured even using unpolarized electron-positron beams. The relevant diagram calculations are briefly discussed and the results of selected (box) diagram computations are shown.Comment: similar to Phys. Rev. D version, but corrected figs. 4, 5, 6 (factor four