Mikhail I. Vysotskii

Electroweak radiative corrections in Z-boson decays

We present a detailed review of the electroweak radiative corrections to the Z-boson decay, in the framework of the Minimal Standard Model (MSM). 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 t-quark mass, mt, and strong coupling constant αs. Allowed range for the value of the Higgs boson mass, mH, is discussed. Various details of calculations are described in 16 appendices.

Critical velocities

We consider a few thought experiments of radial motion of massive particles in the gravitational fields outside and inside various celestial bodies: Earth, Sun, black hole. All other interactions except gravity are disregarded. For the outside motion there exists a critical value of coordinate velocity : particles with v vc are decelerated like photons. Particles moving inside a body with constant density have no critical velocity; they are always accelerated. We consider also the motion of a ball inside a tower, when it is thrown from the top (bottom) of the tower and after elastically bouncing at the bottom (top) comes back to the original point. The total time of flight is the same in these two cases if the initial proper velocity v0 is equal to .