New Upper Limit on the Axion-Photon Coupling with an Extended CAST Run with a Xe-Based Micromegas Detector.

Hypothetical axions provide a compelling explanation for dark matter and could be emitted from the hot solar interior. The CERN Axion Solar Telescope has been searching for solar axions via their back conversion to x-ray photons in a 9-T 10-m long magnet directed toward the Sun. We report on an extended run with the International Axion Observatory pathfinder detector, doubling the previous exposure time.

Experimental Search for Invisible Dark Matter Axions around 22 μeV.

The axion has emerged as the most attractive solution to two fundamental questions in modern physics related to the charge-parity invariance in strong interactions and the invisible matter component of our Universe. Over the past decade, there have been many theoretical efforts to constrain the axion mass based on various cosmological assumptions. Interestingly, different approaches from independent groups produce good overlap between 20 and 30  μeV.

Quenching of a no-insulation high-temperature superconducting magnet.

We report details on the quenching incident of an 18 T high-temperature superconducting (HTS) magnet, which occurred in December 2020. It has been received that the no-insulation (NI) design of an HTS magnet is relatively safe in quenching. However, the NI design could not completely prevent the magnet from quenching and damaging the associated system.

Extended Axion Dark Matter Search Using the CAPP18T Haloscope.

We report an extended search for the axion dark matter using the CAPP18T haloscope. The CAPP18T experiment adopts innovative technologies of a high-temperature superconducting magnet and a Josephson parametric converter. The CAPP18T detector was reconstructed after an unexpected incident of the high-temperature superconducting magnet quenching.

Near-Quantum-Noise Axion Dark Matter Search at CAPP around 9.5 μeV.

We report the results of an axion dark matter search over an axion mass range of 9.39-9.51  μeV.

Axion Dark Matter Search around 4.55 μeV with Dine-Fischler-Srednicki-Zhitnitskii Sensitivity.

We report an axion dark matter search at Dine-Fischler-Srednicki-Zhitnitskii sensitivity with the CAPP-12TB haloscope, assuming axions contribute 100% of the local dark matter density. The search excluded the axion-photon coupling g_{aγγ} down to about 6.2×10^{-16}  GeV^{-1} over the axion mass range between 4.

Search for Dark Matter Axions with CAST-CAPP.

The CAST-CAPP axion haloscope, operating at CERN inside the CAST dipole magnet, has searched for axions in the 19.74 μeV to 22.47 μeV mass range.

Searching for Invisible Axion Dark Matter with an 18 T Magnet Haloscope.

We report the first search results for axion dark matter using an 18 T high-temperature superconducting magnet haloscope. The scan frequency ranges from 4.7789 to 4.

Axion dark matter: How to see it?

The axion is a highly motivated elementary particle that could address two fundamental questions in physics-the strong charge-parity (CP) problem and the dark matter mystery. Experimental searches for this hypothetical particle started reaching theoretically interesting sensitivity levels, particularly in the micro-electron volt (gigahertz) region. They rely on microwave resonators in strong magnetic fields with signals read out by quantum noise limited amplifiers.

First Results from an Axion Haloscope at CAPP around 10.7 μeV.

The Center for Axion and Precision Physics Research at the Institute for Basic Science is searching for axion dark matter using ultralow temperature microwave resonators. We report the exclusion of the axion mass range 10.7126-10.

Search for Invisible Axion Dark Matter with a Multiple-Cell Haloscope.

We present the first results of a search for invisible axion dark matter using a multiple-cell cavity haloscope. This cavity concept was proposed to provide a highly efficient approach to high-mass regions compared to the conventional multiple-cavity design, with larger detection volume, simpler detector setup, and a unique phase-matching mechanism. Searches with a double-cell cavity superseded previous reports for the axion-photon coupling over the mass range between 13.

Performance of an impedance-variable pulsed high-power electron-beam accelerator based on energy efficient transmission.

Versatile high-power pulsed electron-beam accelerators that meet the requirements of pulsed high-power specifications are needed for appropriate applications in medical industry, defense, and other industries. The pulsed electron beam accelerator comprising a Marx generator and Blumlein pulse forming line (PFL) is designed to accelerate the electron beams at the level of 1 MeV when electrostatically discharging. The performance specifications of Marx generators consisting of a 100 kV DC power supply, R-L-C circuit, and high voltage switch are at a maximum 800 kV.

Axion Dark Matter Search around 6.7 μeV.

An axion dark matter search with the CAPP-8TB haloscope is reported. Our results are sensitive to axion-photon coupling g_{aγγ} down to the QCD axion band over the axion mass range between 6.62 and 6.

Design, construction, and operation of an 18 T 70 mm no-insulation (RE)BaCuO magnet for an axion haloscope experiment.

We report the design, construction, and operation results of an 18 T 70 mm cold-bore high temperature superconductor (HTS) no-insulation (NI) magnet, which is developed for an axion haloscope experiment. The magnet consists of 44 double-pancake coils wound with multi-width and multi-thickness REBaCuO (RE = rare earth) tapes. Owing to the NI feature, the magnet is highly compact; is 162 mm in outer diameter and 476 mm tall; and provides an environment of 0.

Switching Magnetism and Superconductivity with Spin-Polarized Current in Iron-Based Superconductor.

We explore a new mechanism for switching magnetism and superconductivity in a magnetically frustrated iron-based superconductor using spin-polarized scanning tunneling microscopy (SPSTM). Our SPSTM study on single-crystal Sr_{2}VO_{3}FeAs shows that a spin-polarized tunneling current can switch the Fe-layer magnetism into a nontrivial C_{4} (2×2) order, which cannot be achieved by thermal excitation with an unpolarized current. Our tunneling spectroscopy study shows that the induced C_{4} (2×2) order has characteristics of plaquette antiferromagnetic order in the Fe layer and strongly suppresses superconductivity.

Correlation of Fe-Based Superconductivity and Electron-Phonon Coupling in an FeAs/Oxide Heterostructure.

Interfacial phonons between iron-based superconductors (FeSCs) and perovskite substrates have received considerable attention due to the possibility of enhancing preexisting superconductivity. Using scanning tunneling spectroscopy, we studied the correlation between superconductivity and e-ph interaction with interfacial phonons in an iron-based superconductor Sr_{2}VO_{3}FeAs (T_{c}≈33  K) made of alternating FeSC and oxide layers. The quasiparticle interference measurement over regions with systematically different average superconducting gaps due to the e-ph coupling locally modulated by O vacancies in the VO_{2} layer, and supporting self-consistent momentum-dependent Eliashberg calculations provide a unique real-space evidence of the forward-scattering interfacial phonon contribution to the total superconducting pairing.

Observation of coherent elastic neutrino-nucleus scattering.

The coherent elastic scattering of neutrinos off nuclei has eluded detection for four decades, even though its predicted cross section is by far the largest of all low-energy neutrino couplings. This mode of interaction offers new opportunities to study neutrino properties and leads to a miniaturization of detector size, with potential technological applications. We observed this process at a 6.

Phase Locking the Spin Precession in a Storage Ring.

This Letter reports the successful use of feedback from a spin polarization measurement to the revolution frequency of a 0.97  GeV/c bunched and polarized deuteron beam in the Cooler Synchrotron (COSY) storage ring in order to control both the precession rate (≈121  kHz) and the phase of the horizontal polarization component. Real time synchronization with a radio frequency (rf) solenoid made possible the rotation of the polarization out of the horizontal plane, yielding a demonstration of the feedback method to manipulate the polarization.

Miniaturized two-stack Blumlein pulser with a variable repetition-rate for non-thermal irreversible-electroporation experiments.

Non-thermal irreversible electroporation (NTIRE) to avoid thermal damage to cells during intense DC ns pulsed electric fields (nsPEFs) is a recent modality for medical applications. This mechanism, related to bioelectrical dynamics of the cell, is linked to the effect of a DC electric field and a threshold effect with an electrically stimulated membrane for the charge distribution in the cell. To create the NTIRE condition, the pulse width of the nsPEF should be shorter than the charging time constant of the membrane related to the cell radius, membrane capacitance, cytoplasm resistivity, and medium resistivity.

A storage ring experiment to detect a proton electric dipole moment.

A new experiment is described to detect a permanent electric dipole moment of the proton with a sensitivity of 10 e ⋅ cm by using polarized "magic" momentum 0.7 GeV/c protons in an all-electric storage ring. Systematic errors relevant to the experiment are discussed and techniques to address them are presented.

How to Reach a Thousand-Second in-Plane Polarization Lifetime with 0.97-GeV/c Deuterons in a Storage Ring.

We observe a deuteron beam polarization lifetime near 1000 s in the horizontal plane of a magnetic storage ring (COSY). This long spin coherence time is maintained through a combination of beam bunching, electron cooling, sextupole field corrections, and the suppression of collective effects through beam current limits. This record lifetime is required for a storage ring search for an intrinsic electric dipole moment on the deuteron at a statistical sensitivity level approaching 10^{-29}  e cm.

New Method for a Continuous Determination of the Spin Tune in Storage Rings and Implications for Precision Experiments.

A new method to determine the spin tune is described and tested. In an ideal planar magnetic ring, the spin tune-defined as the number of spin precessions per turn-is given by ν(s)=γG (γ is the Lorentz factor, G the gyromagnetic anomaly). At 970  MeV/c, the deuteron spins coherently precess at a frequency of ≈120  kHz in the Cooler Synchrotron COSY.