scholarly journals Search for inelastic scattering of WIMP dark matter in XENON1T

2021 ◽  
Vol 103 (6) ◽  
Author(s):  
E. Aprile ◽  
J. Aalbers ◽  
F. Agostini ◽  
M. Alfonsi ◽  
L. Althueser ◽  
...  
Keyword(s):  
Dark Matter ◽  
Inelastic Scattering

scholarly journals Exothermic dark mesons in light of electron recoil excess at XENON1T

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Soo-Min Choi ◽  
Hyun Min Lee ◽  
Bin Zhu
Keyword(s):  
Dark Matter ◽  
Inelastic Scattering ◽  
Small Mass ◽  
Density Current ◽  
Flavor Symmetry ◽  
Color Group ◽  
Dark Sector ◽  
The Standard Model ◽  
Electron Recoil ◽  
Relic Density

Abstract We consider a novel mechanism to realize exothermic dark matter with dark mesons in the limit of approximate flavor symmetry in a dark QCD. We introduce a local dark U(1)′ symmetry to communicate between dark mesons and the Standard Model via Z′ portal by partially gauging the dark flavor symmetry with flavor-dependent charges for cancelling chiral anomalies in the dark sector. After the dark local U(1)′ is broken spontaneously by the VEV of a dark Higgs, there appear small mass splittings between dark quarks, consequently, leading to small split masses for dark mesons, required to explain the electron recoil excess in XENON1T by the inelastic scattering between dark mesons and electron. We propose a concrete benchmark model for split dark mesons based on SU(3)L× SU(3)R/SU(3)V flavor symmetry and SU(Nc) color group and show that there exists a parameter space making a better fit to the XENON1T data with two correlated peaks from exothermic processes and satisfying the correct relic density, current experimental and theoretical constraints.

scholarly journals Deformed shell model study of event rates for WIMP-73Ge scattering

2017 ◽  
Vol 32 (38) ◽  
pp. 1750210 ◽  
Author(s):  
R. Sahu ◽  
V. K. B. Kota
Keyword(s):  
Dark Matter ◽  
Inelastic Scattering ◽  
Shell Model ◽  
Energy Levels ◽  
Supersymmetric Model ◽  
Dark Matter Candidate ◽  
Detection Rates ◽  
Hartree Fock ◽  
Model Study ◽  
Event Rates

The event detection rates for the Weakly Interacting Massive Particles (WIMP) (a dark matter candidate) are calculated with [Formula: see text]Ge as the detector. The calculations are performed within the deformed shell model (DSM) based on Hartree–Fock states. First, the energy levels and magnetic moment for the ground state and two low-lying positive parity states for this nucleus are calculated and compared with experiment. The agreement is quite satisfactory. Then the nuclear wave functions are used to investigate the elastic and inelastic scattering of WIMP from [Formula: see text]Ge; inelastic scattering, especially for the [Formula: see text] transition, is studied for the first time. The nuclear structure factors which are independent of supersymmetric model are also calculated as a function of WIMP mass. The event rates are calculated for a given set of nucleonic current parameters. The calculation shows that [Formula: see text]Ge is a good detector for detecting dark matter.

scholarly journals Elastic and inelastic scattering of cosmic rays on sub-GeV dark matter

2020 ◽  
Vol 102 (10) ◽  
Author(s):  
Gang Guo ◽  
Yue-Lin Sming Tsai ◽  
Meng-Ru Wu ◽  
Qiang Yuan
Keyword(s):  
Dark Matter ◽  
Cosmic Rays ◽  
Inelastic Scattering ◽  
Elastic And Inelastic Scattering

scholarly journals INVESTIGATION ON LIGHT DARK MATTER

2008 ◽  
Vol 23 (26) ◽  
pp. 2125-2140 ◽  
Author(s):  
R. BERNABEI ◽  
P. BELLI ◽  
F. CAPPELLA ◽  
R. CERULLI ◽  
C. J. DAI ◽  
...  
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Inelastic Scattering ◽  
Galactic Center ◽  
Sterile Neutrino ◽  
Direct Detection ◽  
Dark Matter Candidate ◽  
Annual Modulation ◽  
The Standard Model ◽  
Supersymmetric Models

Some extensions of the Standard Model provide Dark Matter candidate particles with sub-GeV mass. These Light Dark Matter particles have been considered for example in Warm Dark Matter scenarios (e.g. the keV scale sterile neutrino, axino or gravitino). Moreover, MeV scale DM candidates have been proposed in supersymmetric models and as source of the 511 keV line from the Galactic center. In this paper the possibility of direct detection of a Light Dark Matter candidate is investigated considering the inelastic scattering processes on the electron or on the nucleus targets. Some theoretical arguments are developed and related phenomenological aspects are discussed. Allowed volumes and regions for the characteristic phenomenological parameters of the considered scenarios are derived from the DAMA/NaI annual modulation data.

Analysis of STEM micrographs of thick objects

1978 ◽  
Vol 36 (2) ◽  
pp. 106-107
Author(s):  
S. Golladay
Keyword(s):  
Inelastic Scattering ◽  
Multiple Scattering ◽  
Mass Distribution ◽  
Cross Sections ◽  
Phase Contrast ◽  
Image Point ◽  
Contrast Effects ◽  
Total Cross Sections ◽  
Elastic And Inelastic Scattering

The theory of multiple scattering has been worked out by Groves and comparisons have been made between predicted and observed signals for thick specimens observed in a STEM under conditions where phase contrast effects are unimportant. Independent measurements of the collection efficiencies of the two STEM detectors, calculations of the ratio σe/σi = R, where σe, σi are the total cross sections for elastic and inelastic scattering respectively, and a model of the unknown mass distribution are needed for these comparisons. In this paper an extension of this work will be described which allows the determination of the required efficiencies, R, and the unknown mass distribution from the data without additional measurements or models. Essential to the analysis is the fact that in a STEM two or more signal measurements can be made simultaneously at each image point.

Temperature Dependence of the Critical Electron Dose for Fatty Acid Monolayers

1982 ◽  
Vol 40 ◽  
pp. 78-79
Author(s):  
Kenneth H. Downing ◽  
Robert M. Glaeser
Keyword(s):  
Electron Beam ◽  
Fatty Acid ◽  
Inelastic Scattering ◽  
Temperature Dependence ◽  
Structural Damage ◽  
Direct Result ◽  
Second Step ◽  
Strong Temperature Dependence ◽  
Electron Dose ◽  
Covalent Bonds

The structural damage of molecules irradiated by electrons is generally considered to occur in two steps. The direct result of inelastic scattering events is the disruption of covalent bonds. Following changes in bond structure, movement of the constituent atoms produces permanent distortions of the molecules. Since at least the second step should show a strong temperature dependence, it was to be expected that cooling a specimen should extend its lifetime in the electron beam. This result has been found in a large number of experiments, but the degree to which cooling the specimen enhances its resistance to radiation damage has been found to vary widely with specimen types.

The Resolution and Contrast in Biological Sections Determined by Inelastic and Elastic Scattering

1973 ◽  
Vol 31 ◽  
pp. 224-225
Author(s):  
D. L. Misell
Keyword(s):  
Electron Microscopy ◽  
Adverse Effect ◽  
Elastic Scattering ◽  
Inelastic Scattering ◽  
Amorphous Carbon ◽  
Polymeric Materials ◽  
Chromatic Aberration ◽  
Image Resolution ◽  
Quantitative Estimates ◽  
Elastic Ratio

In the electron microscopy of biological sections the adverse effect of chromatic aberration on image resolution is well known. In this paper calculations are presented for the inelastic and elastic image intensities using a wave-optical formulation. Quantitative estimates of the deterioration in image resolution as a result of chromatic aberration are presented as an alternative to geometric calculations. The predominance of inelastic scattering in the unstained biological and polymeric materials is shown by the inelastic to elastic ratio, I/E, within an objective aperture of 0.005 rad for amorphous carbon of a thickness, t=50nm, typical of biological sections; E=200keV, I/E=16.

Resolving Crystallites in Zirconium Oxide Films

1969 ◽  
Vol 27 ◽  
pp. 140-141
Author(s):  
R.A. Ploc
Keyword(s):  
Electron Microscope ◽  
Inelastic Scattering ◽  
Zirconium Oxide ◽  
Oxide Films ◽  
Optic Axis ◽  
Objective Lens ◽  
Microscope Objective ◽  
Linear Optic ◽  
A Current ◽  
Microscope Objective Lens

The optic axis of an electron microscope objective lens is usually assumed to be straight and co-linear with the mechanical center. No reason exists to assume such perfection and, indeed, simple reasoning suggests that it is a complicated curve. A current centered objective lens with a non-linear optic axis when used in conjunction with other lenses, leads to serious image errors if the nature of the specimen is such as to produce intense inelastic scattering.

An Environmental Wet Cell For High Voltage Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 18-19
Author(s):  
N.J. Tighe ◽  
H.M. Flower ◽  
P.R. Swann
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Image Quality ◽  
Inelastic Scattering ◽  
High Voltage ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
Environmental Cell ◽  
Water Saturated ◽  
High Temperature Gas

A differentially pumped environmental cell has been developed for use in the AEI EM7 million volt microscope. In the initial version the column of gas traversed by the beam was 5.5mm. This permited inclusion of a tilting hot stage in the cell for investigating high temperature gas-specimen reactions. In order to examine specimens in the wet state it was found that a pressure of approximately 400 torr of water saturated helium was needed around the specimen to prevent dehydration. Inelastic scattering by the water resulted in a sharp loss of image quality. Therefore a modified cell with an ‘airgap’ of only 1.5mm has been constructed. The shorter electron path through the gas permits examination of specimens at the necessary pressure of moist helium; the specimen can still be tilted about the side entry rod axis by ±7°C to obtain stereopairs.

The effect of temperature on high-resolution TEM image contrast

1995 ◽  
Vol 53 ◽  
pp. 640-641
Author(s):  
T. Geipel ◽  
W. Mader ◽  
P. Pirouz
Keyword(s):  
Form Factor ◽  
Inelastic Scattering ◽  
Accurate Method ◽  
Waller Factor ◽  
Effect Of Temperature ◽  
Specimen Thickness ◽  
Influence Of Temperature ◽  
Debye Waller Factor ◽  
Influence Of Temperature On ◽  
Atomic Form Factor

Temperature affects both elastic and inelastic scattering of electrons in a crystal. The Debye-Waller factor, B, describes the influence of temperature on the elastic scattering of electrons, whereas the imaginary part of the (complex) atomic form factor, fc = fr + ifi, describes the influence of temperature on the inelastic scattering of electrons (i.e. absorption). In HRTEM simulations, two possible ways to include absorption are: (i) an approximate method in which absorption is described by a phenomenological constant, μ, i.e. fi; - μfr, with the real part of the atomic form factor, fr, obtained from Hartree-Fock calculations, (ii) a more accurate method in which the absorptive components, fi of the atomic form factor are explicitly calculated. In this contribution, the inclusion of both the Debye-Waller factor and absorption on HRTEM images of a (Oll)-oriented GaAs crystal are presented (using the EMS software.Fig. 1 shows the the amplitudes and phases of the dominant 111 beams as a function of the specimen thickness, t, for the cases when μ = 0 (i.e. no absorption, solid line) and μ = 0.1 (with absorption, dashed line).

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