Download or read book Emission of Single and Few Electrons in XENON1T and Limits on Light Dark Matter written by [Study group] XENON Collaboration and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Delayed single- and few-electron emissions plague dual-phase time projection chambers, limiting their potential to search for light-mass dark matter. This paper examines the origins of these events in the XENON1T experiment. Characterization of the intensity of delayed electron backgrounds shows that the resulting emissions are correlated, in time and position, with high-energy events and can effectively be vetoed. In this work we extend previous S2-only analyses down to a single electron. From this analysis, after removing the correlated backgrounds, we observe rates

Download or read book The LZ Dark Matter Search and Development of a New Gas Phase Technique to Characterize Low Level Electron Emission from Electrode Grids written by Wei Ji and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Dark Matter is needed to explain many cosmological observations and therefore has been proposed for many decades, but it awaits direct detection. One of the most popular classes of dark matter candidates is Weakly Interacting Massive Particles (WIMPs), which have masses in the order of 100 GeV and couple to ordinary matter at weak scale. In WIMP direct detection experiments, we look for WIMPs being scattered by nuclei, a process which produces low energy (smaller than 100 keV) recoiling nuclei that can be observed. We are building LZ, a detector looking for WIMPs using liquid xenon in a dual-phase time projection chamber (TPC), at 4850 feet underground at the Sanford Underground Research Facility (SURF) in Lead, South Dakota, USA. LZ aims to achieve the world's highest sensitivity to find WIMPs via WIMP-nucleon interactions. After a brief discussion of dark matter and the LZ experiment, this dissertation presents the details of my study to solve the electron emission problem. The LZ TPC will consist of electrode grids and other metallic surfaces that can emit electrons when operated under voltage. Because the charge measurement in the LZ detector is sensitive to single electrons, electrons from the grids can be both a significant nuisance for data collection and a source of background at low-energies, limiting the sensitivity of the experiment for low-mass WIMPs. This has motivated us to develop a test detector to study how to reduce this background. The test detector consists of a pair of grids biased to high voltage and operated in xenon gas. The electric field between the grid causes the electrons to produce electroluminescence scintillation light that is measured by PMTs. This new technique is sensitive to single electrons emitted by the grids, allowing a measurement of emission currents as low as atto-amperes. We used this detector to study the properties of different grids and to determine what treatments can be done to reduce their electron emission. We found that passivation with citric acid reduces electron emission from stainless steel surfaces. This work was supervised by Professor Thomas Shutt and was completed in collaboration with members of the LZ collaboration and the SLAC LZ group.

Download or read book The Physics of the Dark Photon written by Marco Fabbrichesi and published by Springer Nature. This book was released on 2020-11-23 with total page 85 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is about the dark photon which is a new gauge boson whose existence has been conjectured. Due to its interaction with the ordinary, visible photon, such a particle can be experimentally detected via specific signatures. In this book, the authors review the physics of the dark photon from the theoretical and experimental point of view. They discuss the difference between the massive and the massless case, highlighting how the two phenomena arise from the same vector portal between the dark and the visible sector. A review of the cosmological and astrophysical observations is provided, together with the connection to dark matter physics. Then, a perspective on current and future experimental limits on the parameters of the massless and massive dark photon is given, as well as the related bounds on milli-charged fermions. The book is intended for graduate students and young researchers who are embarking on dark photon research, and offers them a clear and up-to-date introduction to the subject.

Download or read book Inference on Dark Matter in Effective Field Theories written by Vasile Cristian Antochi and published by . This book was released on 2022 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dark Matter Neutrinos and Our Solar System written by Nirmala Prakash and published by World Scientific. This book was released on 2013 with total page 674 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes these issues in terms of links, between cosmology, particle and nuclear physics, as well as between cosmology, atmospheric and terrestrial physics. It studies the constituents of dark matter (classified as hot warm and cold) first in terms of their individual structures, and second, in terms of facilities available to detect these structures. Neutrinos are treated as a separate entity. The last chapter details the real-time stories about the "regions" that were not explored thus far, for lack of advanced technology. Their untold stories (which span up to 2010) are illustrated here datewise in full. The book concludes with the latest news that the Large Hadron Collider team at CERN has finally succeeded in producing 7 trillion electronic Volts of energy by creating head-on-collisions of protons and more protons (in search of God-particle).

Download or read book Light Dark Matter Search with Ionization Signals in XENON1T written by Elena Aprile and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Searches for WIMPs and Axions with the XENON1T Experiment written by Jingqiang Ye and published by . This book was released on 2020 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: Numerous evidence suggests that the majority of matter in the Universe is made of a rarely interacting, non-luminous component, termed dark matter. The XENON1T experiment, utilizing a two-phase liquid xenon time projection chamber, was primarily designed to search for Weakly Interacting Massive Particles (WIMPs), one of the most promising dark matter candidates. With one tonne-year exposure, XENON1T placed the most stringent upper limits of WIMP interaction strength for a large range of WIMP masses and a variety of interaction types. The unprecedented low background in XENON1T also enabled competitive searches for electronic recoil signals. An excess was observed above the known background at low energies and is most prominent between 2 and 3 keVee. This excess favors solar axions over backgrounds at 3.4 sigma, a hypothetical particle arising from the Peccei-Quinn theory to solve the strong CP problem. The resulting axion couplings, however, are in strong tension with astrophysical constraints. The excess can also be explained by beta decays of tritium at 3.2 sigma with a trace amount, which can neither be confirmed nor be rejected with the current knowledge of its production and mitigation mechanisms. If an unconstrained tritium component is added to both alternate and null hypotheses, the significance of the solar axion hypothesis is reduced to 2.0 sigma. This search also includes other electronic recoil signals, such as an enhanced neutrino magnetic moment, bosonic dark matter, and leptophilic dark matter. The prospect of XENONnT, the next-generation experiment that is expected to take science data in 2021, is also discussed in the context of searching for WIMPs and deciphering the excess observed in XENON1T, respectively.

Download or read book Study of Excess Electronic Recoil Events in XENON1T written by Evan Shockley and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis summarizes the original analysis work performed by the author on data from XENON1T, a search for dark matter with a ton-size noble liquid detector operated at Gran Sasso Underground Laboratory in Italy. The nature of dark matter is one of the most open and pressing questions of modern physics, and the unique data acquired with this detector allows the exploration and investigation of several potential scenarios. The analysis of Dr. Shockley searches for a class of elusive elementary particles that interact with the electrons of ordinary atoms, instead of the nucleus. Results of the analysis present, with high confidence, an excess with respect to the expected background. Beyond more mundane explanations, this additional rate of electron-mediated interactions might be a first hint of physics beyond the standard model. This accessible thesis provides details on the detector, the data, and the theory, delivering to the reader an in-depth and coherent picture of the search for physics beyond the standard model.

Download or read book Light from Dark Stars and Light Through Dark Matter written by Veronica Jane Dike and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents progress in two subfields of astrophysics, first in galactic astronomy, describing how a large survey of ground-state silicon monoxide emission can probe asymptotic giant branch stellar envelope expansion, and second in observational cosmology, presenting novel constraints on primordial black holes (PBH) as a fraction of dark matter by leveraging strong gravitational lensing. The Galactic project searched the Very Large Array Bulge Asymmetries and Dynamical Evolution (BAaDE) survey for maser and thermal emission from the $J=1-0, v=0$ ground vibrational state transition. I present results characterizing these sources as a nearby disk population and derive the expansion velocity of the emission region by fitting thermal components of lines to an emission model. For the small number of sources with corresponding carbon monoxide emission, I find the expansion velocities to be similar for both the thermal SiO and CO, evidence that both emissions are produced in the same region above the star where the gas has reached terminal velocity. In the cosmology portion of the thesis, the objective is to use a flux-ratio analysis to put constraints on intermediate-mass PBH as a possible fraction of dark matter. A population of PBH within the dark matter halo of a lensing galaxy would affect the magnification, and therefore the flux ratios, of the images in a quadruply-imaged quasar (quad). By forward-modeling the flux ratios using an Approximate Bayesian Computing technique, I obtain a constraint on PBH within the mass range of $10^4 $M$_{\odot}

Download or read book Light Limits on Dark Matter written by J. C. McDowell and published by . This book was released on 1986 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sources and Detection of Dark Matter and Dark Energy in the Universe written by David Cline and published by Springer Science & Business Media. This book was released on 2013-11-25 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings provide the latest results on dark matter and dark energy research. The UCLA Department of Physics and Astronomy hosted its tenth Dark Matter and Dark Energy conference in Marina del Rey and brought together all the leaders in the field. The symposium provided a scientific forum for the latest discussions in the field. Topics covered at the symposium: •Status of measurements of the equation of state of dark energy and new experiments •The search for missing energy events at the LHC and implications for dark matter search •Theoretical calculations on all forms of dark matter (SUSY, axions, sterile neutrinos, etc.) •Status of the indirect search for dark matter •Status of the direct search for dark matter in detectors around the world •The low-mass wimp search region •The next generation of very large dark matter detectors •New underground laboratories for dark matter search

Download or read book The LZ Dark Matter Experiment written by Kelly M Stifter and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to a compelling body of astrophysical and cosmological evidence, dark matter has come to be accepted as a crucial ingredient of modern cosmology, yet its physical nature remains one of the most pressing questions in the field of physics. One historically favored model of dark matter is weakly interacting massive particles, or WIMPs. LUX-ZEPLIN (LZ) is a next-generation dark matter detector designed to achieve field-leading sensitivity to much of the remaining accessible parameter space within the WIMP dark matter paradigm. To help realize the full-scale LZ detector, the System Test R&D platform was constructed at SLAC National Accelerator Laboratory to validate the performance of critical LZ subsystems at scales approaching or comparable to the LZ design. In this dissertation, I present results showing that the passivation of the high voltage electrodes in citric acid leads to a significant reduction in spontaneous emission of single electrons, potentially limiting a major instrumental background by up to several orders of magnitude and enabling a more sensitive dark matter search. The LZ detector has now been assembled at the Sanford Underground Research Facility (SURF) in Lead, South Dakota and is taking early data. I also give a first look at commissioning data that captured the first light from electrons in the LZ detector, and share methods to validate the in situ performance of the high voltage electrodes.

Download or read book First Dark Matter Search Results from the XENON1T Experiment written by Elena Aprile and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Solar Reflected Dark Matter with XENON1T and XENONnT written by Pueh Leng Tan and published by . This book was released on 2024 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Low mass Limit written by Noah Kurinsky and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The SuperCDMS SNOLAB experiment will be a 20-kg scale Si and Ge direct dark matter detection experiment designed to probe down to 300 MeV in dark matter (DM) mass through DM-nucleus scattering and 500 keV in DM electron scattering. In order to reach these low masses with appreciable sensitivity to dark matter, it needs to achieve very low energy resolution (≤ 10 ev) for nuclear recoils in both detector materials, which will be achieved using a new detector design and operating mode, CDMS HV. This detector is designed to operate at a bias of 100V to convert charges liberated in our detector targets to into phonon energy in order to resolve individual electron-hole pairs. This has never before been achieved in a kg-scale detector. In this thesis, I cover three elements of the design of the CDMS HV detectors. I discuss the detector physics controlling how charges and phonons are generated in our detector crystals, com- paring theory to results of recent experiments carried out at Stanford. I move on to describe the operating principles of our phonon-mediated charge readout, as well as the design of the CDMS HV detector. I then describe the performance tests of early CDMS HV prototypes in conjunction with the SuperCDMS SNOLAB electronics, and discuss the path towards achieving single electron-hole pair resolving detectors at the kg-scale given the performance obtained thus far. As a result of these tests, we were able to refine our noise and sensor dynamics models, and develop new metrics for diagnosing non-ideal sources of noise to aid in reducing coupling of the external environment to our detectors. In order to study the microphysics of phonon and charge production in our target crystals, we fabricated a number of gram-scale devices with various sensor designs in order to separate sensor and environmental effects from intrinsic crystal properties. These devices provided the first successful demonstrating of using voltage to amplify charge energy by production of phonons (the Neganov-Trofimov-Luke effect) in order to resolve electron-hole pairs, and opened up a new regime of dark matter and photon science at the gram-scale that we are just beginning to explore. A first dark matter search was carried out with one of these gram-scale devices, producing world-leading limits on electron-recoiling dark matter between 0.5 and 5 MeV in dark matter mass for multiple form factors. This device achieved a phonon resolution of 10 eV, allowing a single gram-day of exposure to rival kg-days of exposure in the competing liquid-noble based electron-recoil search.

Download or read book Direct Detection of Sub GeV Dark Matter with Semiconductor Targets written by and published by . This book was released on 2016 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dark matter in the sub-GeV mass range is a theoretically motivated but largely unexplored paradigm. Such light masses are out of reach for conventional nuclear recoil direct detection experiments, but may be detected through the small ionization signals caused by dark matter-electron scattering. Semiconductors are well-studied and are particularly promising target materials because their O(1 eV) band gaps allow for ionization signals from dark matter particles as light as a few hundred keV. Current direct detection technologies are being adapted for dark matter-electron scattering. In this paper, we provide the theoretical calculations for dark matter-electron scattering rate in semiconductors, overcoming several complications that stem from the many-body nature of the problem. We use density functional theory to numerically calculate the rates for dark matter-electron scattering in silicon and germanium, and estimate the sensitivity for upcoming experiments such as DAMIC and SuperCDMS. We find that the reach for these upcoming experiments has the potential to be orders of magnitude beyond current direct detection constraints and that sub-GeV dark matter has a sizable modulation signal. We also give the first direct detection limits on sub-GeV dark matter from its scattering off electrons in a semiconductor target (silicon) based on published results from DAMIC. We make available publicly our code, QEdark, with which we calculate our results. Our results can be used by experimental collaborations to calculate their own sensitivities based on their specific setup. In conclusion, the searches we propose will probe vast new regions of unexplored dark matter model and parameter space.

Download or read book Estimating LUX ZEPLIN s Sensitivity to Sub GeV Dark Matter Scattering Off Electrons in Xenon written by Gus Eberlein and published by . This book was released on 2024 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprising 85% of the mass of the universe, dark matter is one of the most pressing outstanding questions of physics. When it comes to directly detecting dark matter, the LUX-ZEPLIN (LZ) experiment has unparalleled sensitivity. We examine the detector's capability to detect sub-GeV dark matter scattering off the electrons in xenon, LZ's scintillation medium. We develop a signal model by calculating the expected DM-electron event rates as a function of electron recoil energy and as a function of the number of freed electrons. Alongside an established backgrounds model, this signal model is used to simulate events in the LZ detector. With this simulated data and a cut-and-count analysis, we are able to estimate cross sections of dark matter-electron scattering down to which LZ can detect the signal over the background. We find that LUX-ZEPLIN will be able to detect certain light dark matter models at a much greater sensitivity than previous direct detection experiments.