No Arabic abstract
Axions and axion-like particles are excellent low-mass dark matter candidates. The MADMAX experiment aims to directly detect galactic axions with masses between $40,mu{rm eV}$ and $400,mu{rm eV}$ by using the axion-induced emission of electromagnetic waves from boundaries between materials of different dielectric constants under a strong magnetic field. Combining many such surfaces, this emission can be significantly enhanced (boosted) using constructive interference and resonances. We present a first proof of principle realization of such a booster system consisting of a copper mirror and up to five sapphire disks. The electromagnetic response of the system is investigated by reflectivity measurements. The mechanical accuracy, calibration process of unwanted reflections and the repeatability of a basic tuning algorithm to place the disks are investigated. We find that for the presented cases the electromagnetic response in terms of the group delay predicted by one-dimensional calculations is sufficiently realized in our setup. The repeatability of the tuning is at the percent level, and would have small impact on the sensitivity of such a booster.
In contrast to WIMPs, light Dark Matter candidates have increasingly come under the focus of scientific interest. In particular the QCD axion is also able to solve other fundamental problems such as CP-conservation in strong interactions. Galactic axions, axion-like particles and hidden photons can be converted to photons at boundaries between materials of different dielectric constants under a strong magnetic field. Combining many such surfaces, one can enhance this conversion significantly using constructive interference and resonances. The proposed MADMAX setup containing 80 high dielectric disks in a SI{10}{tesla} magnetic field would probe the well-motivated mass range of $40$--SI{400}{microelectronvolt}, a range which is at present inaccessible by existing cavity searches. We present the foundations of this approach and its expected sensitivity.
The axion is an intriguing dark matter candidate emerging from the Peccei-Quinn solution to the strong CP problem. Current experimental searches for axion dark matter focus on the axion mass range below 40 $mu$eV. However, if the Peccei-Quinn symmetry is restored after inflation the observed dark matter density points to an axion mass around 100 $mu$eV. A new project based on axion-photon conversion at the transition between different dielectric media is presented. By using $sim 80$ dielectric discs, the emitted power could be enhanced by a factor of $sim 10^5$ over that from a single mirror (flat dish antenna). Within a 10 T magnetic field, this could be enough to detect $sim 100 mu$eV axions with HEMT linear amplifiers. The design for an experiment is proposed. Results from noise, transmissivity and reflectivity measurements obtained in a prototype setup are presented. The expected sensitivity is shown.
Time-Of-Flight (TOF) is a noble technique that is used in Positron Emission Tomography (PET) imaging worldwide. The scintillator based imaging system that is being used around the world for TOF-PET is very expensive. Multi-gap Resistive Plate Chambers (MRPCs) are gaseous detectors which are easy to fabricate, inexpensive and have excellent position and timing resolution. They can be used as a suitable alternative to highly expensive scintillators. For the sole purpose of TOF-PET, a pair of 18 cm $times$ 18 cm, 5 gap, glass-based MRPC modules have been fabricated. Our main aim was to determine the shift in the position of the source (Na-22) with these fabricated MRPCs. In this document, the details of the experimental results will be presented.
In this report we present the status of the MAgnetized Disk and Mirror Axion eXperiment (MADMAX), the first dielectric haloscope for the direct search of dark matter axions in the mass range of 40 to 400 $mu$eV. MADMAX will consist of several parallel dielectric disks, which are placed in a strong magnetic field and with adjustable separations. This setting is expected to allow for an observable emission of axion induced electromagnetic waves at a frequency between 10 and 100 GHz corresponding to the axion mass. The present document orignated from a status report to the DESY PRC in 2019.
The next generation of long-baseline neutrino experiments will be capable of precision measurements of neutrino oscillation parameters, precision neutrino-nucleus scattering, and unprecedented sensitivity to physics beyond the Standard Model. Reduced uncertainties in neutrino fluxes are necessary to achieve high precision and sensitivity in these future precise neutrino measurements. New measurements of hadron-nucleus interaction cross sections are needed to reduce uncertainties of neutrino fluxes. We report measurements of the differential cross-section as a function of scattering angle for proton-carbon interactions with a single charged particle in the final state at beam momenta of 20, 30, and 120 GeV/c. These measurements are the result of a beam test for EMPHATIC, a hadron-scattering and hadron-production experiment. The total, elastic and inelastic cross-sections are also extracted from the data and compared to previous measurements. These results can be used in current and future long-baseline neutrino experiments, and demonstrate the feasibility of future measurements by an upgraded EMPHATIC spectrometer.