##
###
Big Bang, inflation, standard Physics… and the potentialities of new Physics and alternative cosmologies. Present statuts of observational and experimental Cosmology. Open questions and potentialities of alternative cosmologies

Luis Gonzalez-Mestres, L. Bravina, Y. Foka, S. Kabana

2016
*
EPJ Web of Conferences
*

In [1, 2] , we remind the theoretical controversies that had preceded the March 2014 BICEP2 announcement [3, 4] on the polarization of cosmic microwave background radiation (CMB). These open discrepancies had followed the 2013 Planck results [5] [6] [7] . Such a debate [8, 9] on the predictions of inflationary models [10, 11] involved precisely the possible generation of primordial gravitational waves leading to B-modes of the CMB, as a consequence of cosmic inflation. To date, the theoretical
## more »

... e, the theoretical debate continues [12, 13] but experimental announcements have become more decoupled from theoretical controversies. The joint Planck − BICEP2 − Keck Array (PBKA) analysis [14, 15] found no conclusive evidence for the primordial CMB B-modes initially claimed. Actually, as underlined in [16, 17] and later in [1, 2] and in two contributions to this Conference [18, 19] , the theoretical and phenomenological situation remains uncertain and requires a long-term effort together with suitable experimental and observational programs. In particular, as pointed out in [19] , if Quantum Chromodynamics played a crucial role in the transition from hadrons to quarks and gluons as fundamental objects in the 1970s, no equivalent theory exists at present for a possible similar transition from standard particles to preons with a preonic vacuum of which quarks, leptons, gauge bosons... would be excitations (the superbradyon hypothesis, formulated in 1995 [20, 21] ). In spite of this difficulty, a detailed discussion on the possible origin of Quantum Mechanics from a superbradyonic vacuum with a spinorial space-time (SST) geometry is presented in [18] . The standard cosmological model (Big Bang + inflation + ΛCDM) remains far from being welldefined and well-established. In particular, it cannot completely account for recent cosmological observations and analyses by the Planck Collaboration [22] [23] [24] . 2015 Planck studies [25] do not contradict the observed asymmetry between the power spectra of two hemispheres defined by a preferred direction. Such a phenomenon agrees with a natural prediction [26] [27] [28] [29] of the cosmic SST geometry [26, 30] that automatically generates a privileged space direction (PSD) for each comoving observer. Standard cosmological patterns can also be challenged from a more fundamental point of view including the properties of vacuum, the space-time structure and the formation of the Universe [2, 17, 31]. A pre-Big Bang scenario can naturally make the Planck scale useless [27, 28] . As already stressed in [1, 2] and in previous work, alternative cosmologies [32, 33] must be seriously taken into account in the present situation. They can turn out to be more efficient to explain real data than the conventional cosmology based on the standard Big Bang model with inflation. Actually, cosmic inflation has no reason to have existed in a Universe involving a physical vacuum made of superbradyons [20, 21] where signals and correlations can propagate faster than light and free superluminal particles (not tachyons) may have dominated an early phase of the Universe [19, 21] . Similarly, the size of a SST Universe is expected to be much larger than that of the conventional one [1, 31]. Thus, a Universe with a SST geometry can naturally fake [28, 34] a flat standard Universe with an observed small curvature as seen with a conventional approach to cosmological modeling [35] . The present theoretical uncertainties, already discussed in [1, 2], clearly require not only a longterm effort in the theoretical domain, but also strong long-term experimental and observational programs. If CMB studies are a priority task, high-energy cosmic rays are also an important field including the ultra-high energy (UHE) domain where possible violations of the standard principles of Particle Physics and Cosmology can be searched for (see, for instance, [27, 36] and [37, 38] ). In the alternative cosmologies and patterns of Particle Physics considered in [27, 28] and in [1, 2, 18], the standard principles of Physics are local low-energy limits of a more fundamental dynamics for a sector of matter, as already postulated in [20, 21] ) and dealt with in [39] [40] [41] . Together with the search for new particles at high-energy accelerators, the study of ultra-high energy cosmic rays (UHECR) can in particular provide signatures of new physics and new sectors of matter [28, 42] .

doi:10.1051/epjconf/201612602012
fatcat:2cxwktpeovaibmu252iirevdhq