Search

Abstract $$\varLambda $$ Λ -Cold Dark Matter ( $$\varLambda $$ Λ CDM) has been successful at explaining the large-scale structures in the universe but faces severe issues on smaller scales when compared to observations. Introducing self-interactions between dark matter particles claims to provide a solution to the small-scale issues in the $$\varLambda $$ Λ CDM simulations while being consistent with the observations at large scales. The existence of the energy region in which these self-interactions between dark matter particles come close to saturating the S-wave unitarity bound can result in the formation of dark matter bound states called darkonium. In this scenario, all the low energy scattering properties are determined by a single parameter, the inverse scattering length $$\gamma $$ γ . In this work, we set bounds on $$\gamma $$ γ by studying the impact of darkonium on the observations at direct detection experiments using data from CRESST-III and XENON1T. The exclusion limits on $$\gamma $$ γ are then subsequently converted to exclusion limits on the self-interaction cross-section and compared with the constraints from astrophysics and N-body simulations.

Abstract In recent times, the sensitivity of low-mass direct dark matter searches has been limited by unknown low energy backgrounds close to the energy threshold of the experiments known as the low energy excess (LEE). The CRESST experiment utilises advanced cryogenic detectors constructed with different types of crystals equipped with Transition Edge Sensors (TESs) to measure signals of nuclear recoils induced by the scattering of dark matter particles in the detector. In CRESST, this low energy background manifests itself as a steeply rising population of events below 200 eV. A novel detector design named doubleTES using two identical TESs on the target crystal was studied to investigate the hypothesis that the events are sensor-related. We present the first results from two such modules, demonstrating their ability to differentiate between events originating from the crystal’s bulk and those occurring in the sensor or in its close proximity.

Abstract Coherent elastic neutrino-nucleus scattering (CE $$\nu $$ ν NS) poses an irreducible background in the search for dark matter-nucleus elastic scatterings, which is commonly known as the neutrino floor. As direct dark matter search experiments keep improving their sensitivity into so far unexplored regions, they face the challenge of approaching this neutrino floor. A precise description of the CE $$\nu $$ ν NS signal is therefore crucial for the description of backgrounds for future DM searches. In this work we discuss the scenario of detecting neutrinos in low-threshold, high-exposure cryogenic solid state experiments optimized for the search of low-mass dark matter. The energy range considered is completely dominated by solar neutrinos. In absence of any dark matter events, we treat solar neutrinos as the main signal of interest. We show that sensitivity to the flux of neutrinos from different production mechanisms can be achieved. In particular we investigate the sensitivity to the flux of pp and $$^{7}$$ 7 Be neutrinos, as well as CNO neutrinos. Furthermore, we investigate the sensitivity to dark matter signals in the presence of a solar neutrino background for different experimental scenarios, which are defined by three parameters: the target material, the energy threshold and the exposure. We show that experiments with thresholds of $$\mathcal {O}$$ O (eV) and exposures of $$\mathcal {O}$$ O (tonne-years), using $$\hbox {CaWO}_{4}$$ CaWO 4 or $$\hbox {Al}_{2}\hbox {O}_{3}$$ Al 2 O 3 targets, have discovery potential for dark matter interaction cross sections in the neutrino floor.

Abstract Cryogenic scintillating calorimeters are ultra- sensitive particle detectors for rare event searches, particularly for the search for dark matter and the measurement of neutrino properties. These detectors are made from scintillating target crystals generating two signals for each particle interaction. The phonon (heat) signal precisely measures the deposited energy independent of the type of interacting particle. The scintillation light signal yields particle discrimination on an event-by-event basis. This paper presents a likelihood framework modeling backgrounds and a potential dark matter signal in the two-dimensional plane spanned by phonon and scintillation light energies. We apply the framework to data from CaWO $$_4$$ 4 -based detectors operated in the CRESST dark matter search. For the first time, a single likelihood framework is used in CRESST to model the data and extract results on dark matter in one step by using a profile likelihood ratio test. Our framework simultaneously fits (neutron) calibration data and physics (background) data and allows combining data from multiple detectors. Although tailored to CaWO $$_4$$ 4 -targets and the CRESST experiment, the framework can easily be expanded to other materials and experiments using scintillating cryogenic calorimeters for dark matter search and neutrino physics.

Abstract COSINUS is a dark matter (DM) direct search experiment that uses sodium iodide (NaI) crystals as cryogenic calorimeters. Thanks to the low nuclear recoil energy threshold and event-by-event discrimination capability, COSINUS will address the long-standing DM claim made by the DAMA/LIBRA collaboration. The experiment is currently under construction at the Laboratori Nazionali del Gran Sasso, Italy, and employs a large cylindrical water tank as a passive shield to meet the required background rate. However, muon-induced neutrons can mimic a DM signal therefore requiring an active veto system, which is achieved by instrumenting the water tank with an array of photomultiplier tubes (PMTs). This study optimizes the number, arrangement, and trigger conditions of the PMTs as well as the size of an optically invisible region. The objective was to maximize the muon veto efficiency while minimizing the accidental trigger rate due to the ambient and instrumental background. The final configuration predicts a veto efficiency of 99.63 ± 0.16% and 44.4 ± 5.6% in the tagging of muon events and showers of secondary particles, respectively. The active veto will reduce the cosmogenic neutron background rate to 0.11 ± 0.02 cts $$\cdot $$ · kg $$^{-1}\cdot $$ - 1 · year $$^{-1},$$ - 1 , corresponding to less than one background event in the region of interest for the whole COSINUS-1 $$\pi $$ π exposure of 1000 kg $$\cdot $$ · days.

Abstract Diamond operated as a cryogenic calorimeter is an excellent target for direct detection of low-mass dark matter candidates. Following the realization of the first low-threshold cryogenic detector that uses diamond as absorber for astroparticle physics applications, we now present the resulting exclusion limits on the elastic spin-independent interaction cross-section of dark matter with diamond. We measured two 0.175 g CVD (Chemical Vapor Deposition) diamond samples, each instrumented with a Transition Edge Sensor made of Tungsten (W-TES). Thanks to the energy threshold of just 16.8 eV of one of the two detectors, we set exclusion limits on the elastic spin-independent interaction of dark matter particles with carbon nuclei down to dark matter masses as low as 0.122 GeV/c $$^2$$ 2 . This work shows the scientific potential of cryogenic detectors made from diamond and lays the foundation for the use of this material as target for direct detection dark matter experiments.

Abstract Rare-event search experiments located on-surface, such as short-baseline reactor neutrino experiments, are often limited by muon-induced background events. Highly efficient muon vetos are essential to reduce the detector background and to reach the sensitivity goals. We demonstrate the feasibility of deploying organic plastic scintillators at sub-Kelvin temperatures. For the NUCLEUS experiment, we developed a cryogenic muon veto equipped with wavelength shifting fibers and a silicon photo multiplier operating inside a dilution refrigerator. The achievable compactness of cryostat-internal integration is a key factor in keeping the muon rate to a minimum while maximizing coverage. The thermal and light output properties of a plastic scintillation detector were examined. We report first data on the thermal conductivity and heat capacity of the polystyrene-based scintillator UPS-923A over a wide range of temperatures extending below one Kelvin. The light output was measured down to 0.8 K and observed to increase by a factor of 1.61 ± 0.05 compared to 300 K. The development of an organic plastic scintillation muon veto operating in sub-Kelvin temperature environments opens new perspectives for rare-event searches with cryogenic detectors at sites lacking substantial overburden.

Abstract In this work we report the realization of the first low-threshold cryogenic detector that uses diamond as absorber for astroparticle physics applications. We tested two 0.175 g CVD diamond samples, each instrumented with a W-TES. The sensors showed transitions at about 25 mK. We present the performance of the diamond detectors and we highlight the best performing one, where we obtained an energy threshold as low as 16.8 eV. This promising result lays the foundation for the use of diamond for different fields of applications where low threshold and excellent energy resolution are required, as i.e. light dark matter searches and BSM physics with coherent elastic neutrino nucleus scattering.

Abstract The COSINUS (Cryogenic Observatory for SIgnatures seen in Next-generation Underground Searches) experiment aims at the detection of dark matter-induced recoils in sodium iodide (NaI) crystals operated as scintillating cryogenic calorimeters. The detection of both scintillation light and phonons allows performing an event-by-event signal to background discrimination, thus enhancing the sensitivity of the experiment. The choice of using NaI crystals is motivated by the goal of probing the long-standing DAMA/LIBRA results using the same target material. The construction of the experimental facility is foreseen to start by 2021 at the INFN Gran Sasso National Laboratory (LNGS) in Italy. It consists of a cryostat housing the target crystals shielded from the external radioactivity by a water tank acting, at the same time, as an active veto against cosmic ray-induced events. Taking into account both environmental radioactivity and intrinsic contamination of materials used for cryostat, shielding and infrastructure, we performed a careful background budget estimation. The goal is to evaluate the number of events that could mimic or interfere with signal detection while optimising the geometry of the experimental setup. In this paper we present the results of the detailed Monte Carlo simulations we performed, together with the final design of the setup that minimises the residual amount of background particles reaching the detector volume.

Abstract CRESST is one of the most prominent direct detection experiments for dark matter particles with sub-GeV/c $$^2$$ 2 mass. One of the advantages of the CRESST experiment is the possibility to include a large variety of nuclides in the target material used to probe dark matter interactions. In this work, we discuss in particular the interactions of dark matter particles with protons and neutrons of $$^{6}$$ 6 Li. This is now possible thanks to new calculations on nuclear matrix elements of this specific isotope of Li. To show the potential of using this particular nuclide for probing dark matter interactions, we used the data collected previously by a CRESST prototype based on LiAlO $$_2$$ 2 and operated in an above ground test-facility at Max-Planck-Institut für Physik in Munich, Germany. In particular, the inclusion of $$^{6}$$ 6 Li in the limit calculation drastically improves the result obtained for spin-dependent interactions with neutrons in the whole mass range. The improvement is significant, greater than two order of magnitude for dark matter masses below 1 GeV/c $$^2$$ 2 , compared to the limit previously published with the same data.

Abstract In this work, a first cryogenic characterization of a scintillating $$\hbox {LiAlO}_{2}$$ LiAlO 2 single crystal is presented. The results achieved show that this material holds great potential as a target for direct dark matter search experiments. Three different detector modules obtained from one crystal grown at the Leibniz-Institut für Kristallzüchtung (IKZ) have been tested to study different properties at cryogenic temperatures. Firstly, two 2.8 g twin crystals were used to build different detector modules which were operated in an above-ground laboratory at the Max Planck Institute for Physics (MPP) in Munich, Germany. The first detector module was used to study the scintillation properties of $$\hbox {LiAlO}_{2}$$ LiAlO 2 at cryogenic temperatures. The second achieved an energy threshold of ( $$213.02\pm 1.48$$ 213.02 ± 1.48 ) eV which allows setting a competitive limit on the spin-dependent dark matter particle-proton scattering cross section for dark matter particle masses between $$350\,\hbox {MeV/c}^{2}$$ 350 MeV/c 2 and $$1.50\,\hbox {GeV/c}^{2}$$ 1.50 GeV/c 2 . Secondly, a detector module with a 373 g $$\hbox {LiAlO}_{2}$$ LiAlO 2 crystal as the main absorber was tested in an underground facility at the Laboratori Nazionali del Gran Sasso (LNGS): from this measurement it was possible to determine the radiopurity of the crystal and study the feasibility of using this material as a neutron flux monitor for low-background experiments.

Abstract Coherent elastic neutrino–nucleus scattering ($$\hbox {CE}\nu \hbox {NS}$$ CEνNS ) offers a unique way to study neutrino properties and to search for new physics beyond the Standard Model. Nuclear reactors are promising sources to explore this process at low energies since they deliver large fluxes of anti-neutrinos with typical energies of a few MeV. In this paper, a new-generation experiment to study $$\hbox {CE}\nu \hbox {NS}$$ CEνNS is described. The NUCLEUS experiment will use cryogenic detectors which feature an unprecedentedly low-energy threshold and a time response fast enough to be operated under above-ground conditions. Both sensitivity to low-energy nuclear recoils and a high event rate tolerance are stringent requirements to measuring $$\hbox {CE}\nu \hbox {NS}$$ CEνNS of reactor anti-neutrinos. A new experimental site, the Very-Near-Site (VNS), at the Chooz nuclear power plant in France is described. The VNS is located between the two 4.25 $$\hbox {GW}_{\mathrm {th}}$$ GWth reactor cores and matches the requirements of NUCLEUS. First results of on-site measurements of neutron and muon backgrounds, the expected dominant background contributions, are given. In this paper a preliminary experimental set-up with dedicated active and passive background reduction techniques and first background estimations are presented. Furthermore, the feasibility to operate the detectors in coincidence with an active muon veto at shallow overburden is studied. The paper concludes with a sensitivity study pointing out the physics potential of NUCLEUS at the Chooz nuclear power plant.

Abstract The CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) dark matter search experiment aims for the detection of dark matter particles via elastic scattering off nuclei in $$\mathrm {CaWO_4}$$ CaWO4 crystals. To understand the CRESST electromagnetic background due to the bulk contamination in the employed materials, a model based on Monte Carlo simulations was developed using the Geant4 simulation toolkit. The results of the simulation are applied to the TUM40 detector module of CRESST-II phase 2. We are able to explain up to $$(68 \pm 16)\,\mathrm {\%}$$ (68±16)% of the electromagnetic background in the energy range between 1 and $$40\,\mathrm {keV}$$ 40keV .

Abstract In this work, we want to highlight the potential of lithium as a target for spin-dependent dark matter search in cryogenic experiments, with a special focus on the low-mass region of the parameter space. We operated a prototype detector module based on a $$\hbox {Li}_2\hbox {MoO}_4$$ Li2MoO4 target crystal in an above-ground laboratory. Despite the high background environment, the detector sets a competitive limit on spin-dependent interactions of dark matter particles with protons and neutrons for masses between $$0.8~\hbox {GeV/c}^2$$ 0.8GeV/c2 and $$1.5~\hbox {GeV/c}^2$$ 1.5GeV/c2 .

Abstract CRESST is a direct dark matter search experiment, aiming for an observation of nuclear recoils induced by the interaction of dark matter particles with cryogenic scintillating calcium tungstate crystals. Instead of confining ourselves to standard spin-independent and spin-dependent searches, we re-analyze data from CRESST-II using a more general effective field theory (EFT) framework. On many of the EFT coupling constants, improved exclusion limits in the low-mass region (< 3–4 GeV/$$c^2$$ c2 ) are presented.

Abstract Models for light dark matter particles with masses below 1 GeV/c $$^2$$ 2 are a natural and well-motivated alternative to so-far unobserved weakly interacting massive particles. Gram-scale cryogenic calorimeters provide the required detector performance to detect these particles and extend the direct dark matter search program of CRESST. A prototype 0.5 g sapphire detector developed for the $$\nu $$ ν -cleus experiment has achieved an energy threshold of $$E_{th}=(19.7\pm 0.9)$$ E t h = ( 19.7 ± 0.9 ) eV. This is one order of magnitude lower than for previous devices and independent of the type of particle interaction. The result presented here is obtained in a setup above ground without significant shielding against ambient and cosmogenic radiation. Although operated in a high-background environment, the detector probes a new range of light-mass dark matter particles previously not accessible by direct searches. We report the first limit on the spin-independent dark matter particle-nucleon cross section for masses between 140 and 500 MeV/c $$^2$$ 2 .

Abstract We discuss a small-scale experiment, called $$\nu $$ ν -cleus, for the first detection of coherent neutrino–nucleus scattering by probing nuclear-recoil energies down to the 10 eV regime. The detector consists of low-threshold CaWO $$_4$$ 4 and Al $$_2$$ 2 O $$_3$$ 3 calorimeter arrays with a total mass of about 10 g and several cryogenic veto detectors operated at millikelvin temperatures. Realizing a fiducial volume and a multi-element target, the detector enables active discrimination of $$\gamma $$ γ , neutron and surface backgrounds. A first prototype Al $$_2$$ 2 O $$_3$$ 3 device, operated above ground in a setup without shielding, has achieved an energy threshold of $${\sim }20$$ ∼ 20 eV and further improvements are in reach. A sensitivity study for the detection of coherent neutrino scattering at nuclear power plants shows a unique discovery potential (5 $$\sigma $$ σ ) within a measuring time of $${\lesssim }2$$ ≲ 2 weeks. Furthermore, a site at a thermal research reactor and the use of a radioactive neutrino source are investigated. With this technology, real-time monitoring of nuclear power plants is feasible.

Abstract Identifying the nature and origin of dark matter is one of the major challenges for modern astro and particle physics. Direct dark-matter searches aim at an observation of dark-matter particles interacting within detectors. The focus of several such searches is on interactions with nuclei as provided e.g. by weakly interacting massive particles. However, there is a variety of dark-matter candidates favoring interactions with electrons rather than with nuclei. One example are dark photons, i.e., long-lived vector particles with a kinetic mixing to standard-model photons. In this work we present constraints on this kinetic mixing based on data from CRESST-II Phase 2 corresponding to an exposure before cuts of 52 kg-days. These constraints improve the existing ones for dark-photon masses between 0.3 and 0.7 keV/c $$^2$$ 2 .

The original version of this article unfortunately contains mistakes.

Global biodiversity targets have not been met due to weak implementation at the national level. National Biodiversity Strategies and Action Plans (NBSAPs) are central for mainstreaming biodiversity by translating global ambition into national policies. This study analyzes the practical role of global and national biodiversity agendas. Interviews from France, Germany, Honduras, Indonesia, Mexico, Peru, Rwanda, and South Africa show that global targets and NBSAPs have raised awareness, mobilized initiatives, mobilized support for implementation, and fostered accountability. Nevertheless, conflicting interests, weak financial support, and poorly integrated institutional and regulatory structures remain challenges to implementation. Levers for harnessing the role of future NBSAPs to achieve the goals and targets of the Kunming-Montreal Global Biodiversity Framework are: improving communication; defining concrete measures and clear responsibilities; fostering cross-sectoral commitment; enshrining targets into national laws; ensuring adequate public funding; reforming harmful subsidies; ensuring coordination among sectors and levels of governance; and strengthening accountability frameworks.

Introduction Interest in the development of innovative technologies in the health sector has increased due to their potential to improve accessibility, efficacy, quality, and cost-effectiveness of treatment. Based on these considerations, we developed the app Robin Z to support adolescents in psychiatric treatment. Robin Z is intended as an add on therapy-tool. It aims to assess symptoms in real time, offer help in coping with symptoms and everyday life and to support medication adherence. Despite initial encouraging research findings supporting the use of smartphone technology in psychotherapy, it remains unclear whether the consistent use of smartphone technology in outpatient clinics is practical outside of research projects. Thus, it is uncertain whether patients will engage with this technology over an extended period of time and whether clinicians will be willing to integrate this new technology into their routine. In view of these factors, it is crucial to evaluate the use of smartphone apps for their applicability, effectiveness, and efficiency in clinical routine. In our investigation, we want to address these questions and fill the gap between research and clinical practice. Objectives The aim of our evaluation is to identify barriers in clinical implementation plus to assess the usability and applicability of the Robin Z app in clinical practice. Methods We started the clinical implementation of Robin Z in four community-based outpatient services. We collected data of 27 adolescent patients and their caregivers (N=15) over a six-week period. They all completed questionnaires on user-friendliness and satisfaction. Further, user data about mood logs, symptom trajectories, achieved weekly goals and entries for positive reinforcement were gathered to examine the clinical impact of using the app. Results The clinical implementation and evaluation will provide data on feasibility, user-friendliness, clinical implication and satisfaction of patients and therapists with the smartphone app Robin Z. Conclusions Although many apps are available for young people with mental health problems, most of these have not been developed by professionals, and their effectiveness has not been evaluated. To the best of our knowledge, Robin Z is one of the first apps of its kind to be specifically developed by clinical experts as an additional tool to support psychotherapy for adolescent patients. The results of this evaluation are of clinical importance to the field of eMental Health. They will provide preliminary evidence of the clinical utility of the app. In addition, the results will improve our understanding of potential barriers and facilitators to using Robin Z for both patients and therapists. Disclosure of Interest None Declared

Introduction The goal of psychotic disorders has led researchers to focus on early identification of individuals at clinical high risk (CHR) for psychosis and treatment of CHR symptoms. CHR symptoms typically occur in adolescence and young adulthood. This is a very sensitive developmental period, and CHR-state is associated with increased functional impairment. Age-appropriate treatment approaches that address youth-specific interests, complex symptomatology, associated distress, and functional impairment are needed. However, there is a lack of research on treatment strategies for this vulnerable age group. To address this gap, we developed the combined treatment program “Robin” (standardized manual and smartphone app). The treatment program targets CHR symptoms, comorbid symptoms, and improvement of quality of life and daily functioning. The smartphone app “Robin Z” is an add-on treatment tool to support patients between their sessions. While a number of studies using smartphone apps in therapy have shown promising effects with adult psychosis patients, little is known about their use in therapy with minor patients. “Robin Z” is one of the first smartphone apps targeting adolescent patients with CHR or full-blown psychotic symptoms. Objectives The investigation of efficacy of this specific intervention versus treatment as usual Methods Our study was designed as a naturalistic clinical intervention study with a matched controlled design (treatment as usual). A total of 40 help-seeking adolescents (67% female) with CHR symptoms aged 13-18 years (mean age 15.86) were recruited to the intervention condition between September 2017 and May 2022. For the control group, data from 62 patients from a previous study are available and will be matched for age and gender. CHR symptoms, comorbid symptoms, functioning, self-efficacy, and quality of life will be monitored at six time points (baseline, during the treatment phase, immediately after the intervention, and 6, 12, and 24 months later). Results All participants have now completed the intervention phase. In Paris, the first results on treatment effects will be presented at the symposium. This will include baseline data for the intervention group and their intraindividual changes in symptomatology, well-being, and level of functioning during and immediately after treatment. In addition, the results of the first follow up examinations compared to the control group will be presented. Conclusions To our knowledge, this is the first controlled trial to evaluate the effectiveness of a specific treatment for adolescents with early psychosis combined with a smartphone app. The results of our evaluation are of clinical importance and should provide essential information for both the field of eMental Health and the topic of early intervention in psychosis. Disclosure of Interest None Declared

Introduction The construct of a clinical high-risk (CHR) state of psychosis has been established to describe potentially prodromal symptoms which typically appear during adolescence and young adulthood. This is a very sensitive developmental period and the clinical high risk (CHR) is associated with increased functional impairment. To address the specialities in the care for this patient population a specialized outpatient care unit for early intervention in psychosis at the Department of Child and Adolescent Psychiatry and Psychotherapy, Psychiatric University Hospital, of the University Zürich (CAPS) is established. The interdisciplinary team (psychiatrists and psychologists) supports children and adolescents with psychotic disorders or at clinical high risk for developing psychosis. The early intervention service offers specialized assessment, treatment and case management for minors with a first psychosis or CHR-state in an outpatient or inpatient setting as well as by day clinic care. Objectives The evaluation main objective was to get a better understanding about this vulnerable patient group. Therefore we analysed the clinical data about CHR-state, comorbid diagnosis, treatment, medication and hospitalisation of the patients who entered the service for early intervention in psychosis. Methods Participants who entered the service for early intervention in psychosis were followed up in the years 2017-2021 and descriptive analysis was used to summarize the data. For the evaluation of the risk construct the participants have been classified in “no increased risk”, “CHR” or “early onset psychosis” (EOP). Additionally, ICD diagnosis, demographics and treatment (medication, psychotherapy, treatment setting) were assessed. Therapy was either psychotherapy and/or group training called DBT2P (Dialectical behavioral group training for adolescents, to prevent psychiatric disorders). Additionally, the use of a smartphone application “Robin Z”(add-on treatment tool to support the patients between the sessions) was assessed. Results In the last five years we saw 300 patients (112 female, mean age 15.7) who sought the care unit for early intervention. The evaluation of the risk showed that 44 patients had no increased risk, 205 were classified with a CHR and 51 fulfilled the criteria of an early onset psychosis (18.5%). Most of the patients showed comorbid diagnosis, mainly depressive disorders (42%). The data about the treatment will be analyzed for the congress. Conclusions Despite clinical implications, there is little data about early detection and early intervention in psychosis for children and adolescent. Therefore, the evaluation of the clinical data of the CAPS is of clinical importance and expected to add essential information in the fields of prevention and early intervention in psychosis. Disclosure of Interest None Declared