Elementary particles under the lens of the black holes

After a brief review of the historical development and CLASSICAL properties of the BLACK HOLES, we discuss how our present knowledge of some of their QUANTUM properties shed light on the very concept of ELEMENTARY PARTICLE. As an illustration, we discuss in this context the decay of accelerated protons, which may be also relevant to astrophysics.Comment: 6 pages, Proceedings of the XXIII Brazilian National Meeting on Particles Physics and Fields. To appear in special issue of the Brazilian Journal of Physic

Mirror particles and mirror matter: 50 years of speculation and search

This review describes the history of discovery of violation of spatial parity P, charge conjugation parity C, combined parity CP. The hypothesis of existence of mirror particles was called upon by its authors to restore the symmetry between left and right. The review presents the emergence and evolution of the concepts ``mirror particles'' and ``mirror matter''. It could serve as a concise guide to the ``mirror-land''. An important part of the review is the list of about 250 references with their titles.Comment: v.2: major changes of the text and reference

Three-body Unitarity in the Finite Volume

The physical interpretation of lattice QCD simulations, performed in a small volume, requires an extrapolation to the infinite volume. A method is proposed to perform such an extrapolation for three interacting particles at energies above threshold. For this, a recently formulated relativistic $3\to 3$ amplitude based on the isobar formulation is adapted to the finite volume. The guiding principle is two- and three-body unitarity that imposes the imaginary parts of the amplitude in the infinite volume. In turn, these imaginary parts dictate the leading power-law finite-volume effects. It is demonstrated that finite-volume poles arising from the singular interaction, from the external two-body sub-amplitudes, and from the disconnected topology cancel exactly leaving only the genuine three-body eigenvalues. The corresponding quantization condition is derived for the case of three identical scalar-isoscalar particles and its numerical implementation is demonstrated.Comment: 9 pages, 3 figure