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21 pages, 410 KiB

Open AccessArticle

Antistars or Antimatter Cores in Mirror Neutron Stars?

by Zurab Berezhiani

Universe 2022, 8(6), 313; https://doi.org/10.3390/universe8060313 - 31 May 2022

Cited by 12 | Viewed by 2448

The oscillation of the neutron n into mirror neutron

n^{'}

The oscillation of the neutron n into mirror neutron

n^{'}

, its partner from the dark mirror sector, can gradually transform an ordinary neutron star into a mixed star consisting in part of mirror dark matter. The implications of the reverse process taking place in the mirror neutron stars depend on the sign of baryon asymmetry in the mirror sector. Namely, if it is negative, as predicted by certain baryogenesis scenarios, then

\bar{n^{'}} - \bar{n}

transitions create a core of our antimatter gravitationally trapped in the mirror star interior. The annihilation of accreted gas on such antimatter cores could explain the origin of

γ

-source candidates with an unusual spectrum compatible with baryon–antibaryon annihilation, recently identified in the Fermi LAT catalog. In addition, some part of this antimatter escaping after the mergers of mirror neutron stars can produce the flux of cosmic antihelium and also heavier antinuclei which are hunted in the AMS-02 experiment. Full article

(This article belongs to the Special Issue Focus on Dark Matter)

36 pages, 12985 KiB

Open AccessArticle

A Perspective on the Solar Modulation of Cosmic Anti-Matter

by Marius S. Potgieter, O. P. M. Aslam, Driaan Bisschoff and Donald Ngobeni

Physics 2021, 3(4), 1190-1225; https://doi.org/10.3390/physics3040076 - 7 Dec 2021

Cited by 12 | Viewed by 3780

Abstract

Global modulation studies with comprehensive numerical models contribute meaningfully to the refinement of very local interstellar spectra (VLISs) for cosmic rays. Modulation of positrons and anti-protons are investigated to establish how the ratio of their intensity, and with respect to electrons and protons, are changing with solar activity. This includes the polarity reversal of the solar magnetic field which creates a 22-year modulation cycle. Modeling illustrates how they are modulated over time and the particle drift they experience which is significant at lower kinetic energy. The VLIS for anti-protons has a peculiar spectral shape in contrast to protons so that the total modulation of anti-protons is awkwardly different to that for protons. We find that the proton-to-anti-proton ratio between 1–2 GeV may change by a factor of 1.5 over a solar cycle and that the intensity for anti-protons may decrease by a factor of ~2 at 100 MeV during this cycle. A composition is presented of VLIS for protons, deuteron, helium isotopes, electrons, and particularly for positrons and anti-protons. Gaining knowledge of their respective 11 and 22 year modulation is useful to interpret observations of low-energy anti-nuclei at the Earth as tests of dark matter annihilation. Full article

(This article belongs to the Special Issue A Themed Issue in Honor of Professor Reinhard Schlickeiser on the Occasion of His 70th Birthday)

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1 pages, 176 KiB

Open AccessAbstract

Multimessenger Probes for New Physics in the Light of A. Sakharov’s Legacy in Cosmoparticle Physics

by Maxim Yu. Khlopov

Phys. Sci. Forum 2021, 2(1), 2; https://doi.org/10.3390/ECU2021-09271 - 22 Feb 2021

Viewed by 1303

Abstract

The modern, standard cosmological scenario, which reflects, to a large extent, the development of A. D. Sakharov’s legacy in cosmoparticle physics, involves inflation, baryosynthesis and dark matter/energy. The physics of all these elements of the cosmological paradigm lays beyond the standard model (BSM) of elementary particles and involves, in its turn, cosmological probes for its study. To specify this physics, the idea of multimessenger probes of new physics is proposed, involving the set of additional model-dependent consequences of physical models for inflation, baryosynthesis and dark matter. After brief review of the cosmophenomenology of new physics, we concentrate on probes for mechanisms of baryosynthesis—first proposed by A. D. Sakharov—which are of special interest in this context. Antimatter domains formed in the early universe can reflect possible strong nonhomogeneity of baryosynthesis. In the homogeneous and isotropic universe, such nonhomogeneity is determined by specific model-dependent choices of mechanisms of inflation and baryosynthesis. These mechanisms provide tests for the physics, underlying modern cosmology. Constraints on macroscopic antimatter objects or cosmic fluxes of antinuclei provide probes for the corresponding models. Positive evidence for macroscopic antimatter existence leads beyond the standard paradigm of the cosmological scenario and specifies with high precision the parameters of BSM physics. Full article

(This article belongs to the Proceedings of The 1st Electronic Conference on Universe)

59 pages, 1816 KiB

Open AccessArticle

Cosmic-Ray Database Update: Ultra-High Energy, Ultra-Heavy, and Antinuclei Cosmic-Ray Data (CRDB v4.0)

by David Maurin, Hans Peter Dembinski, Javier Gonzalez, Ioana Codrina Mariş and Frédéric Melot

Universe 2020, 6(8), 102; https://doi.org/10.3390/universe6080102 - 24 Jul 2020

Cited by 36 | Viewed by 5831

Abstract

We present an update on CRDB, the cosmic-ray database for charged species. CRDB is based on MySQL, queried and sorted by jquery and table-sorter libraries, and displayed via PHP web pages through the AJAX protocol. We review the modifications made on the structure and outputs of the database since the first release (Maurin et al., 2014). For this update, the most important feature is the inclusion of ultra-heavy nuclei (

Z > 30

), ultra-high energy nuclei (from

10^{15}

10^{20}

eV), and limits on antinuclei fluxes (

Z \leq - 1

for

A > 1

); more than 100 experiments, 350 publications, and 40,000 data points are now available in CRDB. We also revisited and simplified how users can retrieve data and submit new ones. For questions and requests, please contact crdb@lpsc.in2p3.fr. Full article

(This article belongs to the Special Issue High Energy Cosmic Ray Direct Detection)

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18 pages, 409 KiB

Open AccessEditor’s ChoiceReview

Cosmological Probes of Supersymmetric Field Theory Models at Superhigh Energy Scales

by Sergei V. Ketov and Maxim Yu. Khlopov

Symmetry 2019, 11(4), 511; https://doi.org/10.3390/sym11040511 - 9 Apr 2019

Cited by 42 | Viewed by 4050

Abstract

The lack of positive results in searches for supersymmetric (SUSY) particles at the Large Hadron Collider (LHC) and in direct searches for Weakly Interacting Massive Particles (WIMPs) in the underground experiments may hint to a super-high energy scale of SUSY phenomena beyond the reach of direct experimental probes. At such scales the supergravity models based on Starobinsky inflation can provide the mechanisms for both inflation and superheavy dark matter. However, it makes the indirect methods the only way of testing the SUSY models, so that cosmological probes acquire the special role in this context. Such probes can rely on the nontrivial effects of SUSY physics in the early Universe, which are all model-dependent and thus can provide discrimination of the models and their parameters. The nonstandard cosmological features like Primordial Black Holes (PBHs) or antimatter domains in a baryon-asymmetric universe are discussed as possible probes for high energy scale SUSY physics. Full article

(This article belongs to the Special Issue Supersymmetric Field Theory 2018)

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