scholarly journals Migdal effect and photon Bremsstrahlung: improving the sensitivity to light dark matter of liquid argon experiments

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
G. Grilli di Cortona ◽  
A. Messina ◽  
S. Piacentini
Keyword(s):  
Dark Matter ◽  
Energy Transfer ◽  
Bayesian Approach ◽  
Liquid Argon ◽  
Weakly Interacting Massive Particles ◽  
Bremsstrahlung Photon ◽  
Search Region ◽  
Simulated Experiment ◽  
The Earth ◽  
Ultimate Limit

Abstract The search for dark matter weakly interacting massive particles with noble liquids has probed masses down and below a GeV/c2. The ultimate limit is represented by the experimental threshold on the energy transfer to the nuclear recoil. Currently, the experimental sensitivity has reached a threshold equivalent to a few ionization electrons. In these conditions, the contribution of a Bremsstrahlung photon or a so-called Migdal electron due to the sudden acceleration of a nucleus after a collision might be sizable. In the present work, we use a Bayesian approach to study how these effects can be exploited in experiments based on liquid argon detectors. In particular, taking inspiration from the DarkSide-50 public spectra, we develop a simulated experiment to show how the Migdal electron and the Bremsstrahlung photon allow to push the experimental sensitivity down to masses of 0.1 GeV/c2, extending the search region for dark matter particles of previous results. For these masses we estimate the effect of the Earth shielding that, for strongly interacting dark matter, makes any detector blind. Finally, we show how the sensitivity scales for higher exposure.

WIMP event rates in directional experiments: The diurnal variation signature

Open Physics ◽  
2011 ◽  
Vol 9 (3) ◽  
Author(s):  
John Vergados ◽  
Charalampos Moustakidis
Keyword(s):  
Dark Matter ◽  
Diurnal Variation ◽  
Cold Dark Matter ◽  
Vacuum Energy ◽  
Direct Detection ◽  
Weakly Interacting Massive Particles ◽  
The Earth ◽  
Event Rates ◽  
Matter Detection ◽  
Direct Dark Matter

AbstractThe recent WMAP data have confirmed that exotic dark matter together with the vacuum energy (cosmological constant) dominate in the flat Universe. Modern particle theories provide viable cold dark matter candidates with masses in the GeV-TeV region. All such candidates will be called WIMPs (Weakly Interacting Massive Particles). The nature of dark matter can only be unraveled by its direct detection in the laboratory. In this work we present some theoretical elements relevant to the direct dark matter detection experiments, paying particular attention to directional experiments, i.e. experiments in which not only the energy but the direction of the recoiling nucleus is observed. Since the direction of observation is fixed with respect to the Earth, while the Earth is rotating around its axis, in a directional experiment the angle between the direction of observation and the Sun’s direction of motion will change during the day. So, since the event rates sensitively depend on this angle, the observed signal in such experiments will exhibit very interesting and characteristic periodic diurnal variation.

Recent status and prospect of CDEX and CJPL

2015 ◽  
Vol 30 (28n29) ◽  
pp. 1545007 ◽  
Author(s):  
S. K. Liu ◽  
Q. Yue
Keyword(s):  
Dark Matter ◽  
Point Contact ◽  
Germanium Detector ◽  
Liquid Argon ◽  
Weakly Interacting Massive Particles ◽  
Underground Laboratory ◽  
Detector Arrays ◽  
Weakly Interacting ◽  
Massive Particles

The China Dark Matter Experiment (CDEX) aims at the direct searches of light Weakly Interacting Massive Particles (WIMPs) deploying point-contact germanium detector at the China Jinping Underground Laboratory (CJPL), which has about 2400 m of rock overburdened. Results on light WIMPs from the prototype CDEX-0 with a few gram mass and CDEX-1 with a 994 g mass are reported. The CDEX-10 experiment employed a germanium detector arrays and liquid argon anti-Compton is being constructed and tested. The multi-purpose experiment CDEX-1T and the expansion project of CJPL-II will also be discussed.

scholarly journals The DarkSide Multiton Detector for the Direct Dark Matter Search

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
C. E. Aalseth ◽  
P. Agnes ◽  
A. Alton ◽  
K. Arisaka ◽  
D. M. Asner ◽  
...  
Keyword(s):  
Dark Matter ◽  
Time Projection Chamber ◽  
Liquid Argon ◽  
Weakly Interacting Massive Particles ◽  
Low Energy ◽  
Background Suppression ◽  
Dark Matter Search ◽  
Nuclear Recoils ◽  
Time Projection ◽  
Direct Dark Matter

Although the existence of dark matter is supported by many evidences, based on astrophysical measurements, its nature is still completely unknown. One major candidate is represented by weakly interacting massive particles (WIMPs), which could in principle be detected through their collisions with ordinary nuclei in a sensitive target, producing observable low-energy (<100 keV) nuclear recoils. The DarkSide program aims at the WIPMs detection using a liquid argon time projection chamber (LAr-TPC). In this paper we quickly review the DarkSide program focusing in particular on the next generation experiment DarkSide-G2, a 3.6-ton LAr-TPC. The different detector components are described as well as the improvements needed to scale the detector from DarkSide-50 (50 kg LAr-TPC) up to DarkSide-G2. Finally, the preliminary results on background suppression and expected sensitivity are presented.

Search for dark matter from the centre of the Earth with 8 years of IceCube data

2021 ◽  
Vol 16 (11) ◽  
pp. C11012
Author(s):  
G. Renzi
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Weakly Interacting Massive Particles ◽  
The Body ◽  
Data Sets ◽  
Beyond The Standard Model ◽  
Fundamental Physics ◽  
The Earth ◽  
The Standard Model ◽  
Body Self

Abstract Neutrinos have been proved to be unique messengers in the understanding of fundamental physics processes, and in astrophysical data sets they may provide hints of physics beyond the Standard Model. For example, neutrinos could be the key to discerning between various dark matter models that are based on Weakly Interacting Massive Particles (WIMPs). WIMPs can scatter off standard matter nuclei in the vicinity of massive bodies such as the Sun or the Earth, lose velocity, and be gravitationally trapped in the center of the body. Self-annihilation of dark matter into Standard Model particles may produce an observable flux of neutrinos. For the case of the Earth, an excess of neutrinos coming from the center of the planet could indicate WIMP capture and annihilation at the Earth’s core. The IceCube Neutrino Observatory, located at the geographical South Pole, is sensitive to these excess neutrinos. A search has been conducted on 8 years of IceCube data, probing multiple dark matter channels and masses. With this analysis, we show that IceCube has world-leading sensitivity to the spin-independent dark matter-nucleon scattering cross section above a WIMP mass of 100 GeV.

scholarly journals Detecting dark matter with far-forward emulsion and liquid argon detectors at the LHC

2021 ◽  
Vol 103 (7) ◽  
Author(s):  
Brian Batell ◽  
Jonathan L. Feng ◽  
Sebastian Trojanowski
Keyword(s):  
Dark Matter ◽  
Liquid Argon

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 Astrophysical aspects of milli-charged dark matter in a Higgs–Stueckelberg model

2015 ◽  
Vol 30 (18) ◽  
pp. 1550089 ◽  
Author(s):  
A. L. dos Santos ◽  
D. Hadjimichef
Keyword(s):  
Dark Matter ◽  
Weakly Interacting Massive Particles ◽  
Dark Sector ◽  
Minimal Coupling ◽  
Astrophysical Application ◽  
Gauge Sector ◽  
Dark Photon ◽  
The Standard Model ◽  
Vector Bosons ◽  
The Impact

An extension of the Standard Model (SM) is studied, in which two new vector bosons are introduced, a first boson Z' coupled to the SM by the usual minimal coupling, producing an enlarged gauge sector in the SM. The second boson A' field, in the dark sector of the model, remains massless and originates a dark photon γ'. A hybrid mixing scenario is considered based on a combined Higgs and Stueckelberg mechanisms. In a Compton-like process, a photon scattered by a weakly interacting massive particles (WIMP) is converted into a dark photon. This process is studied, in an astrophysical application obtaining an estimate of the impact on stellar cooling of white dwarfs and neutron stars.

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