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[en] Several experiments are discussed for which results are equivalent to the catching and weighing of a photon. It is noted that none of the experiments has proved the rest mass to be zero and that such a proof may be impossible. It is shown by such experiments that the rest mass is less than the limit of accuracy of the experiment. These limits have approached ever closer to zero, and the most recent values are exceedingly small
[en] This article is written as a review of the Hamiltonian formalism for the bigravity with de Rham-Gabadadze-Tolley (dRGT) potential, and also of applications of this formalism to the derivation of the background cosmological equations. It is demonstrated that the cosmological scenarios are close to the standard ΛCDM model, but they also uncover the dynamical behavior of the cosmological term. This term arises in bigravity regardless on the choice of the dRGT potential parameters, and its scale is given by the graviton mass. Various matter couplings are considered.
[en] The relation between the astrophysical/cosmological conditions and the physical nature of the neutrinos is discussed. In the framework of grand unification theory of interactions and elementary particles, the neutrino rest mass plays an important role. The actual experimental state of neutrino rest mass measurements is presented. (orig./GSCH)
[de]Im vorliegenden ersten Teil dieses Aufsatzes wird die enge und wechselseitige Verknuepfung zwischen diesen astrophysikalisch-kosmologischen Bedingungen und der physikalischen Natur der Neutrinos behandelt. Dabei spielt im Rahmen der vereinheitlichten Theorie der Kraefte und Elementarteilchen besonders die Ruhmasse der Neutrinos eine Schluesselrolle. Es wird deshalb auch auf den gegenwaertigen Stand experimenteller Neutrinoruhmassenbestimmungen eingegangen. (orig./GSCH)
[en] Using “complexity=action” proposal we study the growth rate of holographic complexity for Lifshitz and hyperscaling violating geometries. We will consider both one and two sided black branes in an Einstein-Maxwell-Dilaton gravitational theory. We find that in either case Lloyd’s bound is violated and the rate of growth of complexity saturates to a value which is greater than twice the mass of the corresponding black brane. This value reduces to the mass of the black brane in the isotropic case. We show that in two sided black brane the saturation happens from above while for one sided black brane it happens from below.
[en] The KEDR detector is a universal magnetic detector designed for studying the c- and b-quarks and two-photon physics, and is employed at the VEPP-4M e+ e− collider. A specific feature of the experiment is the measurement of absolute beam energy using two methods: the resonant depolarization and the faster but less precise Compton backscattering of laser photons. This allowed a large series of measurements to be performed, in which the accuracy of determination of such fundamental parameters of particles as mass and total and leptonic widths was improved.
[en] The principle of causality yields the important result that the velocity of a material object cannot be equal to or greater than that of light. Combined with special theory of relativity, it leads to the conclusion that, except for photons, particles of zero rest mass cannot exist in nature. Hence neutrinos of all flavours must be massive. (Author)