Modern Physics Letters A

Recent results on the application of the method of the effective quanta to the case of WW scattering are reviewed. In particular, it is reviewed how effective W bosons can be used to compute scattering amplitudes in a generalized Effective W Approximation (gEWA). The physical origin and the expected size of the discrepancy between the exact computation and the gEWA computation are discussed. Particular attention is devoted to the peculiarities of the formulation of the gEWA for processes that involve longitudinal W bosons. These formal results are checked through explicit numerical calculations of both scattering amplitudes and scattering cross-sections. Furthermore, the use of the gEWA for the interpretation and for the presentation of the measurement of WW scattering at the LHC is briefly discussed.

We have constructed coherent states for the higher derivative Pais–Uhlenbeck Oscillator (PUO). In the process, we have suggested a novel way to construct coherent states for the oscillator having only negative energy levels. These coherent states have negative energies in general but their coordinate and momentum expectation values and dispersions behave in an identical manner as that of normal (positive energy) oscillator. The coherent states for the PUO have constant dispersions and a modified Heisenberg Uncertainty Relation. Moreover, under reasonable assumptions on parameters these coherent states can have positive energies.

A multi-dimensional cosmology with FRW type metric having four-dimensional spacetime and d-dimensional Ricci-flat internal space is considered with a higher-dimensional cosmological constant. The classical cosmology in commutative and Doubly Special Relativity–Generalized Uncertainty Principle (DSR–GUP) contexts is studied and the corresponding exact solutions for negative and positive cosmological constants are obtained. In the positive cosmological constant case, it is shown that unlike the commutative as well as GUP cases, in DSR–GUP case both scale factors of internal and external spaces after accelerating phase will inevitably experience decelerating phase leading simultaneously to a big crunch. This demarcation from GUP originates from the difference between the GUP and DSR–GUP algebras. The important result is that unlike GUP which results in eternal acceleration, DSR–GUP at first generates acceleration but prevents the eternal acceleration at late-times and turns it into deceleration.

We elaborate two different methods for extracting from data the relative phase of two amplitudes of some sequential decays of baryons. We also relate this phase to a particular physical angle. Moreover, we suggest how to infer some time-reversal (TR) odd observables — in particular, asymmetries — from data. Last, we comment on the Standard Model (SM) predictions of such asymmetries, showing that most of the decays considered are quite suitable for revealing possible new physics (NP) contributions.

Non-minimally coupled Y(R)-Maxwell gravity which have some interesting solutions may be used to understand dark matter, dark energy, the origin of cosmic magnetic field and the evaluation of the universe. We give some new solutions to the model such as spherically symmetric electric, magnetic and dyon solutions. We point out an existence of an electromagnetic duality transformation for the model.

An explicit form of the magnetic moment tensor operator for non-Dirac particles with rest spin-1/2 and its essential difference from the spin operator are established. Possible consequences of the last fact for the description of the spin rotation in the magnetic field and for the values of magnetic moments of some nuclei, as well as the impact of this and other facts on the validity of modeling the azimuthal asymmetry of the secondary-scattered protons in polarization ep-experiments are noted.

We study the modifications induced by spacetime anisotropy on the Casimir effect in the case of two parallel plates. Non-perturbative and perturbative regimes are analyzed. In the first case, the Casimir force either vanishes or it reverses its direction which, in any case, makes the proposal untenable. On the other hand, the perturbative model enables us to incorporate appropriately the effects of spacetime anisotropy.