EXCESS workshop: Descriptions of rising low-energy spectra

Abstract

Many low-threshold experiments observe sharply rising event rates of yet unknown origins below a few hundred eV, and larger than expected from known backgrounds. Due to the significant impact of this excess on the dark matter or neutrino sensitivity of these experiments, a collective effort has been started to share the knowledge about the individual observations. For this, the EXCESS Workshop was initiated. In its first iteration in June 2021, ten rare event search collaborations contributed to this initiative via talks and discussions. The contributing collaborations were CONNIE, CRESST, DAMIC, EDELWEISS, MINER, NEWS-G, NUCLEUS, RICOCHET, SENSEI and SuperCDMS. They presented data about their observed energy spectra and known backgrounds together with details about the respective measurements. In this paper, we summarize the presented information and give a comprehensive overview of the similarities and differences between the distinct measurements. The provided data is furthermore publicly available on the workshop's data repository together with a plotting tool for visualization.

44 pages, 20 figures; Editors: A. Fuss, M. Kaznacheeva, F. Reindl, F. Wagner; updated copyright statements and funding information

References in corpus (17)

• Single-electron and single-photon sensitivity with a silicon Skipper CCD
• Searching for low-mass dark matter particles with a massive Ge bolometer operated above-ground
• Search for low-mass WIMPs in a 0.6 kg day exposure of the DAMIC experiment at SNOLAB
• Results on MeV-scale dark matter from a gram-scale cryogenic calorimeter operated above ground
• First results from the NEWS-G direct dark matter search experiment at the LSM
• Commissioning Run of the CRESST-II Dark Matter Search
• A novel large-volume Spherical Detector with Proportional Amplification read-out
• Performance of the EDELWEISS-III experiment for direct dark matter searches
• Measurement of the ionization produced by sub-keV silicon nuclear recoils in a CCD dark matter detector
• Ionization Yield in Silicon for eV-Scale Electron-Recoil Processes
• Improved EDELWEISS-III sensitivity for low-mass WIMPs using a profile likelihood approach
• Precision laser-based measurements of the single electron response of SPCs for the NEWS-G light dark matter search experiment
• Observation of muon intensity variations by season with the MINOS Near Detector
• A multiball read-out for the spherical proportional counter
• Measuring the Impact Ionization and Charge Trapping Probabilities in SuperCDMS HVeV Phonon Sensing Detectors
• Optimization and performance of the CryoCube detector for the future RICOCHET low-energy neutrino experiment
• The Skipper CCD for low-energy threshold particle experiments above ground

Cited by in corpus (42)

• Results on sub-GeV Dark Matter from a 10 eV Threshold CRESST-III Silicon Detector
• Testing spin-dependent dark matter interactions with lithium aluminate targets in CRESST-III
• A Stress Induced Source of Phonon Bursts and Quasiparticle Poisoning
• Fast neutron background characterization of the future Ricochet experiment at the ILL research nuclear reactor
• Transition Edge Sensors: Physics and Applications
• Latest observations on the low energy excess in CRESST-III
• First measurements of remoTES cryogenic calorimeters: easy-to-fabricate particle detectors for a wide choice of target materials
• Search for Daily Modulation of MeV Dark Matter Signals with DAMIC-M
• Energy loss in low energy nuclear recoils in dark matter detector materials
• First Limits on Light Dark Matter Interactions in a Low Threshold Two Channel Athermal Phonon Detector from the TESSERACT Collaboration
• Absorption of Axion Dark Matter in a Magnetized Medium
• Confirmation of the spectral excess in DAMIC at SNOLAB with skipper CCDs
• First Demonstration of the HeRALD Superfluid Helium Detector Concept
• Low Energy Backgrounds and Excess Noise in a Two-Channel Low-Threshold Calorimeter
• Aluminum Relaxation as the Source of Excess Low Energy Events in Low Threshold Calorimeters
• Search for Light Dark Matter with NEWS-G at the Laboratoire Souterrain de Modane Using a Methane Target
• A Transition Edge Sensor Operated in Coincidence with a High Sensitivity Athermal Phonon Sensor for Photon Coupled Rare Event Searches
• Low-energy spectrum of the BULLKID detector array operated on surface
• Exploring light dark matter with the Migdal effect in hydrogen-doped liquid xenon
• Cosmic muon flux attenuation methods for superconducting qubit experiments
• Detector development for the CRESST experiment
• First demonstration of a TES based cryogenic Li${}_2$MoO${}_4$detector for neutrinoless double beta decay search
• Characterization of the phonon sensor of the CRYOSEL detector with IR photons
• Spontaneous generation of athermal phonon bursts within bulk silicon causing excess noise, low energy background events and quasiparticle poisoning in superconducting sensors
• Low-Energy Calibration of SuperCDMS HVeV Cryogenic Silicon Calorimeters Using Compton Steps
• Detection and Calibration of Low-Energy Nuclear Recoils for Dark Matter and Neutrino Scattering Experiments
• Production and suppression of delayed light in NaI
• Dark Matter-Electron Scattering Search Using Cryogenic Light Detectors
• Tagging and localisation of ionizing events using NbSi transition edge phonon sensors for Dark Matter searches
• Sensitivity study of a sapphire detector using Coherent Elastic Neutrino-Nucleus Scattering process
• Search for low-mass electron-recoil dark matter using a single-charge sensitive SuperCDMS-HVeV Detector
• Particle background characterization and prediction for the NUCLEUS reactor CE$\nu$NS experiment
• Estimation of waveform deformation with the matched filter
• Neutron capture-induced nuclear recoils as background for CE$\nu$NS~measurements at reactors
• A likelihood framework for cryogenic scintillating calorimeters used in the CRESST dark matter search
• Spontaneous damage annealing reactions as a possible source of low energy excess in semiconductor detectors
• High-Dimensional Bayesian Likelihood Normalisation for CRESST's Background Model
• Modeling the Differential Rate for Signal Interactions in Coincidence with Noise Fluctuations or Large Rate Backgrounds
• What surfaces in the operation of noble liquids dark matter detectors
• Performance of a SuperCDMS HVeV Detector with Sub-eV Energy Resolution and Single Charge-sensitivity
• Neutrino NSI in archaeological Pb
• Prospect of the NUCLEUS Experiment at Chooz for Coherent Elastic Neutrino-Nucleus Scattering and New Physics Searches