Abstract
The CAST-CAPP axion haloscope, operating at CERN inside the CAST dipole magnet, has searched for axions in the 19.74
μ
eV to 22.47
μ
eV mass range. The detection concept follows the ...Sikivie haloscope principle, where Dark Matter axions convert into photons within a resonator immersed in a magnetic field. The CAST-CAPP resonator is an array of four individual rectangular cavities inserted in a strong dipole magnet, phase-matched to maximize the detection sensitivity. Here we report on the data acquired for 4124 h from 2019 to 2021. Each cavity is equipped with a fast frequency tuning mechanism of 10 MHz/ min between 4.774 GHz and 5.434 GHz. In the present work, we exclude axion-photon couplings for virialized galactic axions down to
g
a
γ
γ
= 8 × 10
−14
GeV
−1
at the 90% confidence level. The here implemented phase-matching technique also allows for future large-scale upgrades.
A
bstract
We present results of the Relic Axion Dark-Matter Exploratory Setup (RADES), a detector which is part of the CERN Axion Solar Telescope (CAST), searching for axion dark matter in the 34.67
...μ
eV mass range. A radio frequency cavity consisting of 5 sub-cavities coupled by inductive irises took physics data inside the CAST dipole magnet for the first time using this filter-like haloscope geometry. An exclusion limit with a 95% credibility level on the axion-photon coupling constant of g
aγ
≳ 4 × 10
−
13
GeV
−
1
over a mass range of 34
.
6738
μ
eV
< m
a
<
34
.
6771
μ
eV is set. This constitutes a significant improvement over the current strongest limit set by CAST at this mass and is at the same time one of the most sensitive direct searches for an axion dark matter candidate above the mass of 25
μ
eV. The results also demonstrate the feasibility of exploring a wider mass range around the value probed by CAST-RADES in this work using similar coherent resonant cavities.
Search for chameleons with CAST Anastassopoulos, V.; Arik, M.; Aune, S. ...
Physics letters. B,
10/2015, Letnik:
749, Številka:
C
Journal Article
Recenzirano
Odprti dostop
In this work we present a search for (solar) chameleons with the CERN Axion Solar Telescope (CAST). This novel experimental technique, in the field of dark energy research, exploits both the ...chameleon coupling to matter (βm) and to photons (βγ) via the Primakoff effect. By reducing the X-ray detection energy threshold used for axions from 1 keV to 400 eV CAST became sensitive to the converted solar chameleon spectrum which peaks around 600 eV. Even though we have not observed any excess above background, we can provide a 95% C.L. limit for the coupling strength of chameleons to photons of βγ≲1011 for 1<βm<106.
The EU Factory of the Future (FoF) project COMPOSITION (Ecosystem for COllaborative Manufacturing PrOceSses – Intra- and Interfactory Integration and AutomaTION) aims to develop an Integrated ...Information Management System (IIMS) in order to combine physical world, simulation, planning and forecasting data for enhancing re-configurability, scalability and optimisation of resources and processes inside a factory. In addition, the second aim of this project is to extend locally integrated information management systems into an ecosystem that supports the interchange of data and services between factories and their suppliers, i.e., by incorporating and inter-linking both supply and value chains. In this paper, we present an overview of the COMPOSITION project with a particular focus on the incorporation of data analytics tools with the Manufacturing Decision Support System (MDSS) so as to enhance its functionalities. Furthermore, the connection of data analytics tools with a smart Building Management System (BMS) and Digital Factory Modelling (DFM) techniques for data propagation are presented as well. We show how state-of-the-art techniques and methodologies from the research fields of big data analytics, deep learning and simulation/forecasting are incorporated into the MDSS, and how the system is designed in order to accommodate the data-driven needs of a manufacturing environment.
The most compelling candidates for Dark Matter to day are WIMPs and axions. The applicability of gasesous Time Projection Chambers (TPCs) with Micromesh Gas Structures (Micromegas) to the search of ...these particles is explored within this work. Both particles would produce an extremely low rate at very low energies in particle detectors. Micromegas detectors can provide both low background rates and low energy threshold, due to the high granularity, radiopurity and uniformity of the readout. Small (few cm wide) Micromegas detectors are used to image the axion-induced x-ray signal expected in the CERN Axion Solar Telescope (CAST) experiment. We show the background levels obtained in CAST and the prospects to further reduce them to the values required by the Internation Axion Observatory (IAXO). We also present TREX-DM, a scaled-up version of the Micromegas used in axion research, but this time dedicated to the low-mass WIMP detection. TREX-DM is a high-pressure Micromegas-based TPC designed to host a few hundreds of grams of light nuclei (argon or neon) with energy thresholds potentially at the level of 100 eV. The detector is described in detail, as well as the results of the commissioning and characterization phase on surface. Besides, the background model of TREX-DM is presented, along with the anticipated sensitivity of this search, which could go beyond current experimental limits.
Decision Support Systems are considered as a robust technology able to provide an advantage to several manufacturing companies. As part of the Z-Fact0r EU project, an autonomous and self-adjusted ...inference engine; namely the Early Stage-Decision Support System (ES-DSS) will be deployed. The scope is to facilitate real-time inspection, condition monitoring and control - diagnosis at the shop-floor, utilizing continuously mine multiple data streams and run the suitable models to monitor operations and quality performance, to classify products on the basis of quality metrics, as well to predict occurrence of defects and deviations from production and quality requirements.
The CERN Beamline for Schools Competition gives high school students the opportunity to perform an experiment of their design using the T9 facility. Our team, 'Relatively Special', was fortunate ...enough to be joint winners of this global event and travel to CERN for a unique adventure. This paper gives an account of our story including the application, preparation, experience and the overall effect which it has had on us. We also detail our proposed experiment (Proposal from Relatively Special and Video) which aimed to test the validity of the Lorentz factor with two methods: the time of flight (TOF) of various particles and the decay rate of pions at different momenta. Due to the high sensitivity required for the second method the results were inconclusive, therefore we report only on the results of the first method. We focus on the techniques we used, the setup of detectors, and how they function.
We present a comparative study on the most popular machine learning methods applied to the challenging problem of customer churning prediction in the telecommunications industry. In the first phase ...of our experiments, all models were applied and evaluated using cross-validation on a popular, public domain dataset. In the second phase, the performance improvement offered by boosting was studied. In order to determine the most efficient parameter combinations we performed a series of Monte Carlo simulations for each method and for a wide range of parameters. Our results demonstrate clear superiority of the boosted versions of the models against the plain (non-boosted) versions. The best overall classifier was the SVM-POLY using AdaBoost with accuracy of almost 97% and F-measure over 84%.
PDF
