scholarly journals Anisotropic response measurements of ZnWO4 scintillators to neutrons for developing a direction-sensitive dark matter detector

2020 ◽  
Vol 2020 (2) ◽  
Author(s):  
Juan W Pedersen ◽  
Hiroyuki Sekiya ◽  
Koichi Ichimura
Keyword(s):  
Dark Matter ◽  
Neutron Beam ◽  
Gamma Ray ◽  
Oxygen Nucleus ◽  
Crystal Axis ◽  
Quenching Factor ◽  
Nuclear Recoils

Abstract The scintillation yields of ZnWO$_4$ crystals change depending on the incident direction of particles. This property can be used as a direction-sensitive dark matter detector, so we investigated the ZnWO$_4$ light yields ratio of neutron-induced nuclear recoils to gamma-ray-induced electron recoils (quenching factor). Two surfaces almost perpendicular to the crystal axis of ZnWO$_4$ were irradiated with a quasi-monochromatic neutron beam of 0.885 MeV, and the quenching factors of both surfaces for the oxygen-nucleus recoil in the ZnWO$_4$ crystal were measured. The obtained quenching factors of the two surfaces were $0.235 \pm 0.026$ and $0.199 \pm 0.020$, respectively, confirming 15.3% anisotropy.

scholarly journals Spin-one dark matter and gamma ray signals from the galactic center

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
H. Hernández-Arellano ◽  
M. Napsuciale ◽  
S. Rodríguez
Keyword(s):  
Dark Matter ◽  
Cross Section ◽  
Gamma Ray ◽  
Galactic Center ◽  
Photon Emission ◽  
Scalar Coupling ◽  
Initial State ◽  
Internal Bremsstrahlung ◽  
Resonance Effects ◽  
State Radiation

Abstract In this work we study the possibility that the gamma ray excess (GRE) at the Milky Way galactic center come from the annihilation of dark matter with a (1, 0) ⊕ (0, 1) space-time structure (spin-one dark matter, SODM). We calculate the production of prompt photons from initial state radiation, internal bremsstrahlung, final state radiation including the emission from the decay products of the μ, τ or hadronization of quarks. Next we study the delayed photon emission from the inverse Compton scattering (ICS) of electrons (produced directly or in the prompt decay of μ, τ leptons or in the hadronization of quarks produced in the annihilation of SODM) with the cosmic microwave background or starlight. All these mechanisms yield significant contributions only for Higgs resonant exchange, i.e. for M ≈ MH /2, and the results depend on the Higgs scalar coupling to SODM, gs. The dominant mechanism at the GRE bump is the prompt photon production in the hadronization of b quarks produced in $$ \overline{D}D\to \overline{b}b $$ D ¯ D → b ¯ b , whereas the delayed photon emission from the ICS of electrons coming from the hadronization of b quarks produced in the same reaction dominates at low energies (ω < 0.3 GeV ) and prompt photons from c and τ , as well as from internal bremsstrahlung, yield competitive contributions at the end point of the spectrum (ω ≥ 30 GeV ). Taking into account all these contributions, our results for photons produced in the annihilation of SODM are in good agreement with the GRE data for gs ∈ [0.98, 1.01] × 10−3 and M ∈ [62.470, 62.505] GeV . We study the consistency of the corresponding results for the dark matter relic density, the spin-independent dark matter-nucleon cross-section σp and the cross section for the annihilation of dark matter into $$ \overline{b}b $$ b ¯ b , τ+τ−, μ+μ− and γγ, taking into account the Higgs resonance effects, finding consistent results in all cases.

scholarly journals Effective field theory analysis of dark matter-standard model interactions with spin one mediators

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Fabiola Fortuna ◽  
Pablo Roig ◽  
José Wudka
Keyword(s):  
Field Theory ◽  
Dark Matter ◽  
Standard Model ◽  
Effective Field Theory ◽  
Gamma Ray ◽  
Direct Detection ◽  
Effective Field ◽  
Indirect Detection ◽  
Theory Analysis ◽  
Invisible Decay

Abstract We analyze interactions between dark matter and standard model particles with spin one mediators in an effective field theory framework. In this paper, we are considering dark particles masses in the range from a few MeV to the mass of the Z boson. We use bounds from different experiments: Z invisible decay width, relic density, direct detection experiments, and indirect detection limits from the search of gamma-ray emissions and positron fluxes. We obtain solutions corresponding to operators with antisymmetric tensor mediators that fulfill all those requirements within our approach.

scholarly journals On a Possible Origin of the Gamma-ray Excess around the Galactic Center

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1432
Author(s):  
Dmitry O. Chernyshov ◽  
Andrei E. Egorov ◽  
Vladimir A. Dogiel ◽  
Alexei V. Ivlev
Keyword(s):  
Dark Matter ◽  
Gamma Rays ◽  
Molecular Clouds ◽  
Alternative Explanation ◽  
Gamma Ray ◽  
Galactic Center ◽  
The Self ◽  
Large Area ◽  
Mhd Turbulence ◽  
The Standard Model

Recent observations of gamma rays with the Fermi Large Area Telescope (LAT) in the direction of the inner galaxy revealed a mysterious excess of GeV. Its intensity is significantly above predictions of the standard model of cosmic rays (CRs) generation and propagation with a peak in the spectrum around a few GeV. Popular interpretations of this excess are that it is due to either spherically distributed annihilating dark matter (DM) or an abnormal population of millisecond pulsars. We suggest an alternative explanation of the excess through the CR interactions with molecular clouds in the Galactic Center (GC) region. We assumed that the excess could be imitated by the emission of molecular clouds with depleted density of CRs with energies below ∼10 GeV inside. A novelty of our work is in detailed elaboration of the depletion mechanism of CRs with the mentioned energies through the “barrier” near the cloud edge formed by the self-excited MHD turbulence. This depletion of CRs inside the clouds may be a reason for the deficit of gamma rays from the Central Molecular Zone (CMZ) at energies below a few GeV. This in turn changes the ratio between various emission components at those energies and may potentially absorb the GeV excess by a simple renormalization of key components.

scholarly journals Directionality preservation of nuclear recoils in an emulsion detector for directional dark matter search

2021 ◽  
Vol 2021 (04) ◽  
pp. 047
Author(s):  
A. Alexandrov ◽  
G. De Lellis ◽  
A. Di Crescenzo ◽  
A. Golovatiuk ◽  
V. Tioukov
Keyword(s):  
Dark Matter ◽  
Dark Matter Search ◽  
Nuclear Recoils

scholarly journals A Review of Basic Energy Reconstruction Techniques in Liquid Xenon and Argon Detectors for Dark Matter and Neutrino Physics Using NEST

Instruments ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 13
Author(s):  
Matthew Szydagis ◽  
Grant A. Block ◽  
Collin Farquhar ◽  
Alexander J. Flesher ◽  
Ekaterina S. Kozlova ◽  
...  
Keyword(s):  
Dark Matter ◽  
Neutrino Physics ◽  
Electric Fields ◽  
Direct Detection ◽  
Profile Likelihood ◽  
Liquid Argon ◽  
Energy Scale ◽  
Liquid Xenon ◽  
Nuclear Recoils ◽  
Available Information

Detectors based upon the noble elements, especially liquid xenon as well as liquid argon, as both single- and dual-phase types, require reconstruction of the energies of interacting particles, both in the field of direct detection of dark matter (weakly interacting massive particles WIMPs, axions, etc.) and in neutrino physics. Experimentalists, as well as theorists who reanalyze/reinterpret experimental data, have used a few different techniques over the past few decades. In this paper, we review techniques based on solely the primary scintillation channel, the ionization or secondary channel available at non-zero drift electric fields, and combined techniques that include a simple linear combination and weighted averages, with a brief discussion of the application of profile likelihood, maximum likelihood, and machine learning. Comparing results for electron recoils (beta and gamma interactions) and nuclear recoils (primarily from neutrons) from the Noble Element Simulation Technique (NEST) simulation to available data, we confirm that combining all available information generates higher-precision means, lower widths (energy resolution), and more symmetric shapes (approximately Gaussian) especially at keV-scale energies, with the symmetry even greater when thresholding is addressed. Near thresholds, bias from upward fluctuations matters. For MeV-GeV scales, if only one channel is utilized, an ionization-only-based energy scale outperforms scintillation; channel combination remains beneficial. We discuss here what major collaborations use.

scholarly journals What if dark matter gamma-ray lines come with gluon lines?

2012 ◽  
Vol 86 (8) ◽  
Author(s):  
Xiaoyong Chu ◽  
Thomas Hambye ◽  
Tiziana Scarna ◽  
Michel H. G. Tytgat
Keyword(s):  
Dark Matter ◽  
Gamma Ray
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