Normunds Ralfs Strautnieks

arXiv2026

Probes of lepton flavor symmetry and violation with top quarks in ATLAS and CMS

Measurements of lepton flavor universality (LFU) and searches for charged lepton flavor violation (cLFV) are one of the most straightforward ways of searching for Beyond Standard Model (BSM) physics. The numerous production of top quark pairs at the LHC allows for high precision measurements of LFU ratios and searches for cLFV signatures. Results of the recent measurements and searches from the ATLAS and CMS collaborations using the Run2 dataset with an integrated luminosity of up to 139 $\mathrm{fb}^{-1}$ at center of mass energy of 13 TeV are presented.

hep-ex↗

arXiv2023

Nanocrystalline CaWO$_4$ and ZnWO$_4$ Tungstates for Hybrid Organic-Inorganic X-ray Detectors

Hybrid materials combining an organic matrix and high-Z nanomaterials show potential for applications in radiation detection, allowing unprecedented device architectures and functionality. Herein, novel hybrid organic-inorganic systems were produced using a mixture of tungstate (CaWO$_4$ or ZnWO$_4$) nanoparticles with a P3HT:PCBM blend. The nano-tungstates with a crystallite size of 43 nm for CaWO$_4$ and 30 nm for ZnWO$_4$ were synthesized by the hydrothermal method. Their structure and morphology were characterized by X-ray diffraction and scanning electron microscopy. The hybrid systems were used to fabricate direct conversion X-ray detectors able to operate with zero bias voltage. The detector performance was tested in a wide energy range using monochromatic synchrotron radiation. The addition of nanoparticles with high-Z elements improved the detector response to X-ray radiation compared with that of a pure organic P3HT:PCBM bulk heterojunction cell. The high dynamic range of our detector allows for recording X-ray absorption spectra, including the fine X-ray absorption structure located beyond the absorption edge. The obtained results suggest that nanocrystalline tungstates are promising candidates for application in direct organic-inorganic X-ray detectors.

cond-mat.mtrl-sci↗