Bound-state effects on light-element abundances in gravitino dark matter scenarios

The astronomical dark matter is an essential component of the Universe and yet its nature is still unresolved. It could be made of neutral and massive elementary particles which are their own antimatter partners. These dark matter species undergo mutual annihilations whose effects are briefly reviewed in this article. Dark matter annihilation plays a key role at early times as it sets the relic abundance of the particles once they have decoupled from the primordial plasma. A weak annihilation cross section naturally leads to a cosmological abundance in agreement with observations. Dark matter species subsequently annihilate — or decay — during Big Bang nucleosynthesis and could play havoc with the light element abundances unless they offer a possible solution to the 7 Li problem. They could also reionize the intergalactic medium after recombination and leave visible imprints in the cosmic microwave background. But one of the most exciting aspects of the question lies in the possibility to indirectly detect the dark matter species through the rare antimatter particles — antiprotons, positrons and antideuterons — which they produce as they currently annihilate inside the galactic halo. Finally, the effects of dark matter annihilation on stars is discussed.

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Cosmological Dark Matter

International Journal of Modern Physics D ◽

10.1142/s0218271897000236 ◽

1997 ◽

Vol 06 (04) ◽

pp. 393-407

Author(s):

D. N. Schramm

Keyword(s):

Dark Matter ◽

Light Element ◽

Baryon Density ◽

The Other ◽

X Ray ◽

Element Abundances ◽

Baryonic Density ◽

Cluster Data ◽

The Universe

The basic arguments for cosmological dark matter are reviewed. It is shown that the Big Bange Nucleosynthesis constraints on the cosmological baryon density, when compared with dynamical arguments, demonstrate that the bulk of the baryons are dark and also that the bulk of the matter in the universe is nonbaryonic. The recent extragalactic deuterium observations as well as the other light element abundances were examined in detail as is the argument on the number of neutrino flavors. Arguments from recent MACHO/EROS observations of halo dark matter seem to imply that at least some of the dark baryons are in the halos of galaxies. Comparison of baryonic density arguments with recent x-ray cluster data is also made. Discussion of the interface of density and age arguments is also presented.

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Detecting dark photons from atomic rearrangement in the galaxy

Journal of High Energy Physics ◽

10.1007/jhep04(2021)016 ◽

2021 ◽

Vol 2021 (4) ◽

Author(s):

James Eiger ◽

Michael Geller

Keyword(s):

Dark Matter ◽

Ground State ◽

Bound State ◽

Current Data ◽

Dark Sector ◽

Atomic Process ◽

The Galaxy ◽

Atomic States ◽

Atomic Rearrangement

Abstract We study a new dark sector signature for an atomic process of “rearrangement” in the galaxy. In this process, a hydrogen-like atomic dark matter state together with its anti-particle can rearrange to form a highly-excited bound state. This bound state will then de-excite into the ground state emitting a large number of dark photons that can be measured in experiments on Earth through their kinetic mixing with the photon. We find that for DM masses in the GeV range, the dark photons have enough energy to pass the thresholds of neutrino observatories such as Borexino and Super-Kamiokande that can probe for our scenario even when our atomic states constitute a small fraction of the total DM abundance. We study the corresponding bounds on the parameters of our model from current data as well as the prospects for future detectors.

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Theoretical Predictions of Surface Light Element Abundances in Protostellar and Pre-Main Sequence Phase

Frontiers in Astronomy and Space Sciences ◽

10.3389/fspas.2021.604872 ◽

2021 ◽

Vol 8 ◽

Author(s):

E. Tognelli ◽

S. Degl’Innocenti ◽

P. G. Prada Moroni ◽

L. Lamia ◽

R. G. Pizzone ◽

...

Keyword(s):

Cross Sections ◽

Main Sequence ◽

Light Element ◽

Element Abundance ◽

Light Elements ◽

Convective Envelope ◽

Stellar Envelope ◽

Element Abundances ◽

Stellar Interior ◽

Theoretical Predictions

Theoretical prediction of surface stellar abundances of light elements–lithium, beryllium, and boron–represents one of the most interesting open problems in astrophysics. As well known, several measurements of 7Li abundances in stellar atmospheres point out a disagreement between predictions and observations in different stellar evolutionary phases, rising doubts about the capability of present stellar models to precisely reproduce stellar envelope characteristics. The problem takes different aspects in the various evolutionary phases; the present analysis is restricted to protostellar and pre-Main Sequence phases. Light elements are burned at relatively low temperatures (T from ≈2 to ≈5 million degrees) and thus in the early evolutionary stages of a star they are gradually destroyed at different depths of stellar interior mainly by (p, α) burning reactions, in dependence on the stellar mass. Their surface abundances are strongly influenced by the nuclear cross sections, as well as by the extension toward the stellar interior of the convective envelope and by the temperature at its bottom, which depend on the characteristics of the star (mass and chemical composition) as well as on the energy transport in the convective stellar envelope. In recent years, a great effort has been made to improve the precision of light element burning cross sections. However, theoretical predictions surface light element abundance are challenging because they are also influenced by the uncertainties in the input physics adopted in the calculations as well as the efficiency of several standard and non-standard physical processes active in young stars (i.e. diffusion, radiative levitation, magnetic fields, rotation). Moreover, it is still not completely clear how much the previous protostellar evolution affects the pre-Main Sequence characteristics and thus the light element depletion. This paper presents the state-of-the-art of theoretical predictions for protostars and pre-Main Sequence stars and their light element surface abundances, discussing the role of (p, α) nuclear reaction rates and other input physics on the stellar evolution and on the temporal evolution of the predicted surface abundances.

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Review of strongly-coupled composite dark matter models and lattice simulations

International Journal of Modern Physics A ◽

10.1142/s0217751x16430041 ◽

2016 ◽

Vol 31 (22) ◽

pp. 1643004 ◽

Cited By ~ 37

Author(s):

Graham D. Kribs ◽

Ethan T. Neil

Keyword(s):

Dark Matter ◽

Gauge Theory ◽

Direct Detection ◽

Bound State ◽

New Physics ◽

Abelian Gauge ◽

Strongly Coupled ◽

Abelian Gauge Theory ◽

Lattice Calculations ◽

Composite Description

We review models of new physics in which dark matter arises as a composite bound state from a confining strongly-coupled non-Abelian gauge theory. We discuss several qualitatively distinct classes of composite candidates, including dark mesons, dark baryons, and dark glueballs. We highlight some of the promising strategies for direct detection, especially through dark moments, using the symmetries and properties of the composite description to identify the operators that dominate the interactions of dark matter with matter, as well as dark matter self-interactions. We briefly discuss the implications of these theories at colliders, especially the (potentially novel) phenomenology of dark mesons in various regimes of the models. Throughout the review, we highlight the use of lattice calculations in the study of these strongly-coupled theories, to obtain precise quantitative predictions and new insights into the dynamics.

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The light elements in a helio- and asteroseismic perspective

Proceedings of the International Astronomical Union ◽

10.1017/s1743921310004515 ◽

2009 ◽

Vol 5 (S268) ◽

pp. 387-394

Author(s):

Sylvie Vauclair

Keyword(s):

Main Sequence ◽

Light Element ◽

Heavy Elements ◽

Light Elements ◽

Main Sequence Stars ◽

General Introduction ◽

Helium Content ◽

Element Abundances ◽

The Past

AbstractAsteroseismology is a powerful tool to derive stellar parameters, including the helium content and internal helium gradients, and the macroscopic motions which can lead to lithium, beryllium, and boron abundance variations. Precise determinations of these parameters need deep analyses for each individual stars. After a general introduction on helio and asteroseismology, I first discuss the solar case, the results which have been obtained in the past two decades, and the crisis induced by the new determination of the abundances of heavy elements. Then I discuss asteroseismology in relation with light element abundances, especially for the case of main sequence stars.

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