PandaX-4T and XENONnT have recently reported the first measurement of nuclear recoils induced by the $^8$B solar neutrino flux, through the coherent elastic neutrino-nucleus scattering (CE$ν$NS) channel. As long anticipated, this is an important milestone for dark matter searches as well as for neutrino physics. This measurement means that these detectors have reached exposures such that searches for low mass, $\lesssim 10$ GeV dark matter cannot be analyzed using the background-free paradigm going forward. It also opens a new era for these detectors to be used as neutrino observatories. In this paper we assess the sensitivity of these new measurements to new physics in the neutrino sector. We focus on neutrino non-standard interactions (NSI) and show that -- despite the still moderately low statistical significance of the signals -- these data already provide valuable information. We find that limits on NSI from PandaX-4T and XENONnT measurements are comparable to those derived using combined COHERENT CsI and LAr data, as well as those including the latest Ge measurement. Furthermore, they provide sensitivity to pure $τ$ flavor parameters that are not accessible using stopped-pion or reactor sources. With further improvements of statistical uncertainties as well as larger exposures, forthcoming data from these experiments will provide important, novel results for CE$ν$NS-related physics.
Germanium is the detector material of choice in many rare-event searches looking for low-energy nuclear recoils induced by dark matter particles or neutrinos. We perform a systematic exploration of its quenching factor for sub-keV nuclear recoils, using multiple techniques: photo-neutron sources, recoils from gamma-emission following thermal neutron capture, and a monochromatic filtered neutron beam. Our results point to a marked deviation from the predictions of the Lindhard model in this mostly unexplored energy range. We comment on the compatibility of our data with low-energy processes suc…
The bright scintillation of pure CsI operated at liquid-nitrogen temperature makes of this material a promising dark matter and neutrino detector. We present the first measurement of its quenching factor for nuclear recoils. Our findings indicate it is indistinguishable from that for sodium-doped CsI at room temperature. Additional properties such as light yield, afterglow, scintillation decay properties for electron and nuclear recoils, and energy proportionality are studied over the \mbox{108-165 K} temperature range, confirming the vast potential of this medium for rare-event searches.
We report a measurement of the ionization efficiency of silicon nuclei recoiling with sub-keV kinetic energy in the bulk silicon of a charge-coupled device (CCD). Nuclear recoils are produced by low-energy neutrons ($<$24 keV) from a $^{124}$Sb-$^{9}$Be photoneutron source, and their ionization signal is measured down to 60 eV electron equivalent. This energy range, previously unexplored, is relevant for the detection of low-mass dark matter particles. The measured efficiency is found to deviate from the extrapolation to low energies of the Lindhard model. This measurement also demonstrates th…
Nuclear recoil energy scale in liquid xenon with application to the direct detection of dark matter
我们第一次表明，在液体氙中的核反冲的电子激发的淬灭是很好地描述了Lindhard理论，如果核反冲能量重建使用的组合（闪烁和电离）的能量尺度提出的Shutt { \it et al.}。我们主张通过这种观点，有利于现有的偏好重建核反冲能完全从初级闪烁。我们表明，信号划分成闪烁和电离是很好地描述了由Mesquas-Imel盒模型。我们讨论了直接探测暗物质的液体氙探测器的影响。
A new measurement of the quenching factor for low-energy nuclear recoils in CsI[Na] is presented. Past measurements are revisited, identifying and correcting several systematic effects. The resulting global data are well-described by a physics-based model for the generation of scintillation by ions in this material, in agreement with phenomenological considerations. The uncertainty in the new model is reduced by a factor of four with respect to an energy-independent quenching factor initially adopted as a compromise by the COHERENT collaboration. A significantly improved agreement with Standar…
We examine a recent measurement of the quenching factor (QF) in germanium at 80 K, noticing a number of inconsistencies capable of affecting a claimed agreement with Lindhard's ion-stopping formalism in the sub-keV nuclear recoil energy regime. Namely, an underestimated uncertainty in the energy scale and a missing correction for a large instrumental non-linearity in this scale able to severely distort the QF behavior at low energy, favoring reduced values. The discussion is expanded to inspect the impact of QF model selection on a study of neutrino electromagnetic properties using CE$ν$NS dat…
The effect of nuclear recoil on neutrino oscillations: Toward understanding of short baseline anomalies
Università del Salento（萨伦托大学）；INFN Sezione di Lecce（意大利国家核物理研究所莱切分部）；Institute of Nanotechnology of the National Research Council of Italy, CNR-NANOTEC, Lecce Central Unit（意大利国家研究委员会纳米技术研究所莱切中央单元）
Large composite dark matter states source a scalar binding field that, when coupled to Standard Model nucleons, provides a potential under which nuclei recoil and accelerate to energies capable of ionization, radiation, and thermonuclear reactions. We show that these dynamics are detectable for nucleon couplings as small as $g_n \sim 10^{-17}$ at dark matter experiments, where the greatest sensitivity is attained by considering the Migdal effect. We also explore Type-Ia supernovae and planetary heating as possible means to discover this type of dark matter.
The nuclear recoil effect on the $g$ factor of H- and Li-like heavy ions is evaluated to all orders in $αZ$. The calculations include an approximate treatment of the nuclear size and the electron-electron interaction corrections to the recoil effect. As the result, the second largest contribution to the theoretical uncertainty of the $g$-factor values of $^{208}$Pb$^{79+}$ and $^{238}$U$^{89+}$ is strongly reduced. Special attention is paid to tests of the QED recoil effect on the $g$ factor in experiments with heavy ions. It is found that, while the QED recoil effect on the $g$-factor value i…
We study the basic integral equation in Lindhard's theory describing the energy given to atomic motion by nuclear recoils in a pure material when the atomic binding energy is taken into account. The numerical solution, which depends only on the slope of the velocity-proportional electronic stopping power and the binding energy, leads to an estimation of the ionization efficiency which is in good agreement with the available experimental measurements for Si and Ge. In this model, the quenching factor for nuclear recoils features a cut-off at an energy equal to twice the assumed binding energy. …
Can Nuclear Recoils and Solar Neutrinos Resolve the Composition of Singlino-Higgsino Dark Matter?
Henan Institute of Science and Technology（河南科技学院）；Henan Normal University（河南师范大学）；Institute of Theoretical Physics, Chinese Academy of Sciences（中国科学院理论物理研究所）
Recent progress in phonon-mediated detectors with eV-scale nuclear recoil energy sensitivity requires an understanding of the effect of the crystalline defects on the energy spectrum expected from dark matter or neutrino coherent scattering. We have performed molecular dynamics simulations to determine the amount of energy stored in the lattice defects as a function of the recoil direction and energy. This energy can not be observed in the phonon measurement, thus affecting the observed energy spectrum compared to the underlying true recoil energy spectrum. We describe this effect for multiple…
Crystal damage events such as tracks and point defects have been used to record and detect radiation for a long time and recently they have been proposed as a means for dark matter detection. Color centers can be read out optically and we propose a scheme based on selective plane illumination microscopy for sub-micron imaging of large volumes corresponding to kilogram mass detectors. This class of detectors would be passive and would operate at room temperature. We apply these concepts to the detection of reactor neutrinos using coherent elastic neutrino nucleus scattering (CEvNS). Crystal dam…
Scintillation response of cryogenic CsI to few-keV and sub-keV nuclear recoils
University of Chicago（芝加哥大学）；Donostia International Physics Center (DIPC)（多诺西亚国际物理中心）；Ikerbasque, Basque Foundation for Science（伊克尔巴斯基克，巴斯克科学基金会）；Instituto de Física Corpuscular, CSIC & Universitat de València（粒子物理研究所，西班牙国家科学研究委员会与瓦伦西亚大学）
Now that conventional weakly interacting massive particle (WIMP) dark matter searches are approaching the neutrino floor, there has been a resurgence of interest in detectors with sensitivity to nuclear recoil directions. A large-scale directional detector is attractive in that it would have sensitivity below the neutrino floor, be capable of unambiguously establishing the galactic origin of a purported dark matter signal, and could serve a dual purpose as a neutrino observatory. We present the first detailed analysis of a 1000 m$^3$-scale detector capable of measuring a directional nuclear re…
High-Energy Nuclear Recoils from Boosted Dark Matter for the LZ 248-keV Event: Beyond the Halo-Dependent High-Velocity Tail
Jazan University（扎赞大学）；University of South Dakota（南达科他大学）；University of Kansas（堪萨斯大学）；Chungnam National University（忠南国立大学）；Jeonbuk National University（全北国立大学）；Korea Institute for Advanced Study（韩国高等研究院）；Institute for Basic Science（基础科学研究院）
Nuclear Recoils from Invisible Neutron-Pair Annihilation and the LZ event
Tohoku University（东北大学）；Kavli IPMU (WPI), UTIAS, University of Tokyo（东京大学宇宙线研究所（ Kavli IPMU ））；University of Sheffield（谢菲尔德大学）；The University of Manchester（曼彻斯特大学）
LZ Nuclear-Recoil Excess from Boosted Light Magnetic Dipole-dipole Dark Matter
Wuyi University（五邑大学）；Nanjing University（南京大学）；National Taiwan University（台湾大学）；Phenikaa University（菲尼亚卡大学）；University of Oslo（奥斯陆大学）；University of California, Los Angeles（加州大学洛杉矶分校）
For the interpretation of past and future direct searches for dark matter (DM) particles, it is important to be able to provide accurate predictions for event rates and spectra under a variety of possible and viable assumptions in a computationally efficient way. While there exists a few tools to compute DM induced nuclear recoil spectra, 'obscura' is not limited to nuclear targets. Instead its main focus lies on sub-GeV DM searches probing electron recoils which typically requires methods from atomic and condensed matter physics. In the context of sub-GeV DM searches, new ideas such as target…
A Freeze-In Interpretation of the LZ High-Energy Nuclear Recoil Event
Georg-August-Universität Göttingen（哥廷根大学）；Dublin Institute for Advanced Studies（都柏林高等研究院）；Helsinki Institute of Physics, Gustaf Hällströmin katu 2a, FI-00014 Helsinki, Finland（赫尔辛基物理研究所）；Lund University（隆德大学）；Universidade de Aveiro（阿威罗大学）；Universidade do Minho（米尼奥大学）
We report a serious kinematics problem in the bremsstrahlung photon part of the order-$α$ outer (model independent) radiative correction calculations for those neutron (and nuclear beta) decay observables (like electron-neutrino correlation parameter measurement) where the proton (recoil particle) is detected. The so-called neutrino-type radiative correction calculations, which fix the neutrino direction in the bremsstrahlung photon integrals, use 3-body decay kinematics to connect the unobserved neutrino direction with the observed electron and proton (recoil particle) momenta. But the presen…
Previous work has argued that the DAMA annual modulation signal might be due to electron recoils in plasma dark matter models. A specific model assuming mirror dark matter and featuring collisional shielding of a detector due to Earth-bound dark matter was put forward by this author [arXiv:1806.04293]. That explanation predicted a low energy electron recoil signal in the XENON1T experiment. In light of the excess of electron recoils observed in XENON1T, we re-examine that model's predictions for both DAMA and XENON1T.
An excess of events of unknown origin at low energies below 1 keV has been observed in multiple low-threshold dark matter detectors. Depending on the target material, nuclear recoil events at these energies may cause lattice defects, in which case a part of the true recoil energy is stored in the defect and not observed in the phonon detector. If the threshold for defect creation is sharp, this effect leads to a prominent feature in the observed recoil spectrum. Electronic recoils at low energies do not create defects and therefore the feature in the observed spectrum is not expected in that c…
