Fri·Jun 28, 2024Friday·June 28, 2024

1. 01*

   New Spin Structure Constraints on Hyperfine Splitting and Proton Size

   David Ruth🇺🇸 · Karl Slifer🇺🇸 · Jian-Ping Chen🇺🇸 · Carl E. Carlson🇺🇸 · Franziska Hagelstein🇩🇪 · Vladimir Pascalutsa🇩🇪 · Alexandre Deur🇺🇸 · Sebastian Kuhn🇺🇸 · Marco Ripani🇮🇹 · Xiaochao Zheng🇺🇸 · Ryan Zielinski🇺🇸 · Chao Gu🇺🇸

   The 1S hyperfine splitting in hydrogen is measured to an impressive ppt precision and will soon be measured to ppm precision in muonic hydrogen. The latter measurement will rely on theoretical predictions, which are limited by knowledge of the proton polarizability effect ${\Delta }_{\text{pol}}$. Data-driven evaluations of ${\Delta }_{\text{pol}}$ have long been in significant tension with baryon chiral perturbation theory. Here we present improved results for ${\Delta }_{\text{pol}}$ driven by new spin structure data, reducing the long-standing tension between theory and experiment and halving the dominating uncertainty in hyperfine splitting calculations.

   nucl-exnucl-thphysics.atom-phPLB(2024)·13 citations
2. 02*

   Final results of the measurement to search for rare decays of naturally occurring osmium isotopes with ultra-low background gamma-ray spectrometry

   P.Belli🇮🇹 · R.Bernabei🇮🇹 · F.Cappella🇮🇹 · V.Caracciolo🇮🇹 · R.Cerulli🇮🇹 · F.A.Danevich🇺🇦 · V.Yu.Denisov🇺🇦 · A.Incicchitti🇮🇹 · D.V.Kasperovych🇺🇦 · V.V.Kobychev🇺🇦 · G.P.Kovtun🇺🇦 · M.Laubenstein🇮🇹 and 6 other authors

   A long-term measurement was conducted to search for $\alpha$, double-$\alpha$ and double-$\beta$ decays with $\gamma$ quanta emission in naturally occurring osmium isotopes. This study took advantage of two ultra-low background HPGe detectors and one ultra-low background BEGe detector at the Gran Sasso National Laboratory (LNGS) of the INFN. Over almost 5 years of data were taken using high-purity osmium samples of approximately 173 g. The half-life limits set for a decays of ${}^{184}$Os to the first $2^{+}$ 103.6 keV excited level of ${}^{180}$W ($T_{1/2}>9.3\times 10^{15}$ yr) and of ${}^{186}$Os to the first $2^{+}$ 100.1 keV of ${}^{182}$W ($T_{1/2}>4.8\times 10^{17}$ yr) exceed substantially the present theoretical predictions that are at level of $T_{1/2}\sim (0.6-3)\times 10^{15}$ yr for ${}^{184}$Os and $T_{1/2}\sim (0.3-2)\times 10^{17}$ yr for ${}^{186}$Os. New half-life limits on the 2EC and EC${\beta }^{+}$ decay of ${}^{184}$Os to the ground and excited levels of ${}^{184}$W were set at level of $T_{1/2}>10^{16}-10^{17}$ yr; a lower limit on the $2{\beta }^{-}$ decay of ${}^{192}$Os to the $2^{+}$ 316.5 keV excited level of ${}^{192}$Pt was estimated as $T_{1/2}>6.1\times 10^{20}$ yr. The half-life limits for $2\alpha$ decay of ${}^{189}$Os and ${}^{192}$Os were set for the first time at level of $T_{1/2}>10^{20}$ yr.

   nucl-exEPJA(2024)·3 citations
3. 03*

   Frequency ratio of the ${}^{229\mathrm{m}}$Th nuclear isomeric transition and the ${}^{87}$Sr atomic clock

   Chuankun Zhang🇺🇸 · Tian Ooi🇺🇸 · Jacob S. Higgins🇺🇸 · Jack F. Doyle🇺🇸 · Lars von der Wense · Kjeld Beeks🇨🇭 · Adrian Leitner · Georgy Kazakov🇦🇹 · Peng Li🇨🇳 · Peter G. Thirolf🇩🇪 · Thorsten Schumm🇦🇹 · Jun Ye🇺🇸

   Optical atomic clocks${}^{1,2}$ use electronic energy levels to precisely keep track of time. A clock based on nuclear energy levels promises a next-generation platform for precision metrology and fundamental physics studies. Thorium-229 nuclei exhibit a uniquely low energy nuclear transition within reach of state-of-the-art vacuum ultraviolet (VUV) laser light sources and have therefore been proposed for construction of the first nuclear clock${}^{3,4}$. However, quantum state-resolved spectroscopy of the ${}^{229m}$Th isomer to determine the underlying nuclear structure and establish a direct frequency connection with existing atomic clocks has yet to be performed. Here, we use a VUV frequency comb to directly excite the narrow ${}^{229}$Th nuclear clock transition in a solid-state CaF${}_2$ host material and determine the absolute transition frequency. We stabilize the fundamental frequency comb to the JILA ${}^{87}$Sr clock${}^2$ and coherently upconvert the fundamental to its 7th harmonic in the VUV range using a femtosecond enhancement cavity. This VUV comb establishes a frequency link between nuclear and electronic energy levels and allows us to directly measure the frequency ratio of the ${}^{229}$Th nuclear clock transition and the ${}^{87}$Sr atomic clock. We also precisely measure the nuclear quadrupole splittings and extract intrinsic properties of the isomer. These results mark the start of nuclear-based solid-state optical clock and demonstrate the first comparison of nuclear and atomic clocks for fundamental physics studies. This work represents a confluence of precision metrology, ultrafast strong field physics, nuclear physics, and fundamental physics.

   ↳ physics.atom-phnucl-exphysics.opticsquant-phNature(2024)·116 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.