scholarly journals Asymmetric dark matter from semi-annihilation

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Avirup Ghosh ◽  
Deep Ghosh ◽  
Satyanarayan Mukhopadhyay
Keyword(s):  
Dark Matter ◽  
Cp Violation ◽  
Chemical Potential ◽  
Unstable State ◽  
Annihilation Process ◽  
Leading Order ◽  
Complex Scalar ◽  
Pair Annihilation ◽  
S Matrix ◽  
Asymmetric Dark Matter

Abstract We show that a general semi-annihilation scenario, in which a pair of dark matter (DM) particles annihilate to an anti-DM, and an unstable state that can mix with or decay to standard model states, can lead to particle anti-particle asymmetry in the DM sector. The present DM abundance, including the CP-violation in the DM sector and the resulting present asymmetry are determined entirely by a single semi-annihilation process at next-to-leading order. For large CP-violation in this process, we find that a nearly complete asymmetry can be obtained in the DM sector, with the observed DM density being dominated by the (anti-)DM particle. The presence of additional pair-annihilation processes can modify the ratio of DM and anti-DM number densities further, if the pair-annihilation is active subsequent to the decoupling of the semi-annihilation. For such a scenario, the required CP-violation for generating the same present asymmetry is generically much smaller, as compared to the scenario with only semi-annihilation present. We show that a minimal model with a complex scalar DM with cubic self-interactions can give rise to both semi- and pair-annihilations, with the required CP-violation generated at one-loop level. We also find that the upper bound on the DM mass from S-matrix unitarity in the purely asymmetric semi-annihilation scenario, with maximal CP-violation, is around 15 GeV, which is much stronger than in the WIMP and previously considered asymmetric DM cases, due to the required large non-zero chemical potential for such asymmetric DM.

scholarly journals Filtered asymmetric dark matter during the Peccei-Quinn phase transition

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
M. Ahmadvand
Keyword(s):  
Phase Transition ◽  
Dark Matter ◽  
Gravitational Waves ◽  
Order Phase Transition ◽  
Annihilation Process ◽  
Density Spectrum ◽  
First Order ◽  
First Order Phase Transition ◽  
Asymmetric Dark Matter ◽  
First Order Phase

Abstract In this paper, we propose a bubble filtering-out mechanism for an asymmetric dark matter scenario during the Peccei-Quinn (PQ) phase transition. Based on a QCD axion model, extended by extra chiral neutrinos, we show that the PQ phase transition can be first order in the parameter space of the model and regarding the PQ symmetry breaking scale, the mechanism can generate PeV-scale heavy neutrinos as a dark matter candidate. Considering a CP-violating source, during the phase transition, discriminating between the neutrino and antineutrino number density, we find the observed dark matter relic abundance, such that the setup can be applied to the first order phase transition with different strengths. We then calculate effective couplings of the QCD axion addressing the strong CP problem within the model. We also study the energy density spectrum of gravitational waves generated from the first order phase transition and show that the signals can be detected by future ground-based detectors such as Einstein Telescope. In particular, for a visible heavy axion case of the model, it is shown that gravitational waves can be probed by DECIGO and BBO interferometers. Furthermore, we discuss the dark matter-standard model neutrino annihilation process as a source for the creation of PeV-scale neutrinos.

Theoretical Analysis of Oxygen Diffusion in monoclinic HfO2

2003 ◽  
Vol 786 ◽  
Author(s):  
Minoru Ikeda ◽  
Georg Kresse ◽  
Toshihide Nabatame ◽  
Akira Toriumi
Keyword(s):  
Oxygen Vacancy ◽  
Oxygen Atom ◽  
Diffusion Process ◽  
Nearest Neighbor ◽  
Chemical Potential ◽  
Annihilation Process ◽  
Interstitial Oxygen ◽  
Middle Range ◽  
Pair Annihilation ◽  
Charge States

ABSTRACTIn this report, we present the detailed analysis of the interstitial oxygen (O2+, O0, O2-) diffusion in monoclinic HfO2 (hafnia) using the first principles calculations. The interstitial oxygen atom kicks out the oxygen atom at the 3-fold-site and occupies the 3-fold-site. And then the newly kicked-out interstitial oxygen atom jumps to the nearest neighbor site and couples again with the atoms at the crystal sites. This kick-out- mechanism is valid for all charge states of the interstitial oxygen in monoclinic HfO2. In hafnia, the interstitial oxygen atom can take 3 charge states (+2, 0, -2) depending on the chemical potential (Ef), whereas the oxygen-vacancy in hafnia can get +2 or 0 charge state being dependent on Ef. In the lower range of Ef, O2+ and O0 might contribute. In the middle range of Ef, the O2- does not contribute to the diffusion process in hafnia because of the pair annihilation process between O2- and oxygen vacancy (V2+) defect pair. We can simulate such a pair annihilation process in hafnia. In the higher range, O2- might contribute the diffusion process.

scholarly journals Kinetic mixing, dark photons and extra dimensions. Part III. Brane localized dark matter

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Thomas G. Rizzo ◽  
George N. Wojcik
Keyword(s):  
Dark Matter ◽  
Extra Dimensions ◽  
Model Building ◽  
New Physics ◽  
Model Complexity ◽  
Complex Scalar ◽  
Dark Photon ◽  
Complex Models ◽  
The Cost ◽  
D Model

Abstract Extra dimensions have proven to be a very useful tool in constructing new physics models. In earlier work, we began investigating toy models for the 5-D analog of the kinetic mixing/vector portal scenario where the interactions of dark matter, taken to be, e.g., a complex scalar, with the brane-localized fields of the Standard Model (SM) are mediated by a massive U(1)D dark photon living in the bulk. These models were shown to have many novel features differentiating them from their 4-D analogs and which, in several cases, avoided some well-known 4-D model building constraints. However, these gains were obtained at the cost of the introduction of a fair amount of model complexity, e.g., dark matter Kaluza-Klein excitations. In the present paper, we consider an alternative setup wherein the dark matter and the dark Higgs, responsible for U(1)D breaking, are both localized to the ‘dark’ brane at the opposite end of the 5-D interval from where the SM fields are located with only the dark photon now being a 5-D field. The phenomenology of such a setup is explored for both flat and warped extra dimensions and compared to the previous more complex models.

scholarly journals Strong CP violation in spin-1/2 singly charmed baryons

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Y. Ünal ◽  
Ulf-G. Meißner
Keyword(s):  
Perturbation Theory ◽  
Dipole Moment ◽  
Form Factor ◽  
Cp Violation ◽  
Mass Shell ◽  
Chiral Expansion ◽  
Renormalization Scheme ◽  
Leading Order ◽  
Chiral Perturbation ◽  
Charmed Baryons

Abstract We report on the calculation of the CP-violating form factor F3 and the corresponding electric dipole moment for charmed baryons in the spin-1/2 sector generated by the QCD θ-term. We work in the framework of covariant baryon chiral perturbation theory within the extended-on-mass-shell renormalization scheme up to next-to-leading order in the chiral expansion.

scholarly journals Minimal scoto-seesaw mechanism with spontaneous CP violation

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
D. M. Barreiros ◽  
F. R. Joaquim ◽  
R. Srivastava ◽  
J. W. F. Valle
Keyword(s):  
Dark Matter ◽  
Cp Violation ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Discrete Symmetry ◽  
Double Beta Decay ◽  
Neutrino Masses ◽  
Seesaw Mechanism ◽  
Cosmological Observations ◽  
Scalar Singlet

Abstract We propose simple scoto-seesaw models to account for dark matter and neutrino masses with spontaneous CP violation. This is achieved with a single horizontal $$ {\mathcal{Z}}_8 $$ Z 8 discrete symmetry, broken to a residual $$ {\mathcal{Z}}_2 $$ Z 2 subgroup responsible for stabilizing dark matter. CP is broken spontaneously via the complex vacuum expectation value of a scalar singlet, inducing leptonic CP-violating effects. We find that the imposed $$ {\mathcal{Z}}_8 $$ Z 8 symmetry pushes the values of the Dirac CP phase and the lightest neutrino mass to ranges already probed by ongoing experiments, so that normal-ordered neutrino masses can be cornered by cosmological observations and neutrinoless double beta decay experiments.

scholarly journals Twin Higgs Asymmetric Dark Matter

2015 ◽  
Vol 115 (12) ◽  
Author(s):  
Isabel García García ◽  
Robert Lasenby ◽  
John March-Russell
Keyword(s):  
Dark Matter ◽  
Asymmetric Dark Matter

scholarly journals Asymmetric dark matter annihilation as a test of non-standard cosmologies

2013 ◽  
Vol 2013 (08) ◽  
pp. 003-003 ◽  
Author(s):  
Graciela B Gelmini ◽  
Ji-Haeng Huh ◽  
Thomas Rehagen
Keyword(s):  
Dark Matter ◽  
Dark Matter Annihilation ◽  
Asymmetric Dark Matter
Sign in / Sign up

Export Citation Format

Share Document