2025/08/24 by Liu, Peifan, Gerharz, Miriam, Marx-Glowna, Berit +37 · 1 citation
#FOS: Physical sciences #Nuclear Experiment (nucl-ex) #Optics (physics.optics) #Other Condensed Matter (cond-mat.other) #Quantum Physics (quant-ph)
paper · doi:10.48550/arxiv.2508.17538
The 45Sc nuclear transition from the ground to the isomeric state at 12.389~keV, with a lifetime of 0.46~s, exhibits an extraordinarily narrow natural width of 1.4~feV and a quality factor ≃ 1019 -- surpassing those of the most precise atomic clocks -- making 45Sc a compelling platform for advanced metrology and nuclear clocks. Here we investigate how closely the spectral width and quality factor of the solid-state 45Sc resonance can approach these natural limits. Using the European X-ray Free-Electron Laser, we confirm the isomer's lifetime via time-delayed incoherent Kα,β fluorescence and observe previously unreported elastic fluorescence, yielding a partial internal conversion coefficient of 390(60). The absence of a clear nuclear forward scattering signal beyond a 2-ms delay implies environmental broadening of at least 500~Γ0 under experimental conditions, placing bounds on solid-state decoherence mechanisms. These findings set new experimental benchmarks for solid-state nuclear clock development.