International Journal of Modern Physics E

Time-reversal-invariance non-conservation has for the first time been unequivocally demonstrated in a direct measurement at CPLEAR. One then can ask the question: What about tests of time-reversal-invariance in systems other than the kaon system? Tests of time-reversal-invariance can be distinguished as belonging to two classes: the first one deals with parity violating (P-odd)/time-reversal-invariance-odd (T-odd) interactions, while the second one deals with P-even/T-odd interactions (assuming CPT conservation this implies C-conjugation non-conservation). Limits on a P-odd/T-odd interaction follow from measurements of the electric dipole moment of the neutron (with a present upper limit of 6 × 10^-26 e.cm [95% C.L.]). It provides a limit on a P-odd/T-odd pion-nucleon coupling constant which is less than 10^-4 times the weak interaction strength. Experimental limits on a P-even/T-odd interaction are much less stringent. Following the standard approach of describing the nucleon-nucleon interaction in terms of meson exchanges it can be shown that only charged rho-meson exchange and A₁-meson exchange can lead to a P-even/T-odd interaction. The better constraints stem from measurements of the electric dipole moment of the neutron and from measurements of charge-symmetry breaking in neutron-proton elastic scattering. The latter experiments were executed at TRIUMF (497 and 347 MeV) and at IUCF (183 MeV). Weak decay experiments may provide limits which will possibly be comparable. All other experiments, like gamma decay experiments, detailed balance experiments, polarization–analyzing power difference determinations, and five-fold correlation experiments with polarized incident nucleons and aligned nuclear targets, have been shown to be at least an order of magnitude less sensitive. The question then emerges: is there room for further experimentation?

The critical behavior of fragment production is studied within a Lattice Gas Model in the canonical ensemble. Finite size effects on the liquid-gas phase transition are analyzed by a direct calculation of the partition function, and it is shown that phase coexistence and phase transition are relevant concepts even for systems of a few tens of particles. Critical exponents are extracted from the behavior of the fragment production yield as a function of temperature by means of a finite size scaling. The result is that in a finite system well defined critical signals can be found at supercritical (Kertész line) as well as subcritical densities inside the coexistence zone.

A quantum logical alternative "Either non-measure preservation Or unitary evolution" exists in the framework of Schroedinger's theory. This explains irreversibility and allows to describe both time-symmetric and time-asymmetric processes in Hermitian quantum theory. The CPT and Noether's theorems remain valid in chronotopology. The Bohr-Einstein controversy, Wigner's conjecture and the Poincaré's non-recurrence are naturally explained. Extended numerical calculations correctly predict the CP- and T-symmetry violation coefficients |η_2π⁰|, |η_π^±|, |η_μ^±|, |η_e^±|, and their phase angles: arg(η)=ϕ_2π⁰, ϕ_π^±, ϕ_μ^±, ϕ_e^± for the K⁰, -decays. A relationship is discovered between the mixing factor and the relevant matrix elements. The ratio "matter/antimatter" appears as temperature dependent in the Universe, antimatter decays prevailing at around T≥ 10²⁴ Kelvin.