Wed·Dec 18, 2024Wednesday·December 18, 2024

1. 01*

   Feasibility Study of Measuring ${\Lambda }^0\to n{\pi }^0$ Using a High-Granularity Zero-Degree Calorimeter at the Future Electron-Ion Collider

   Sebouh J. Paul🇺🇸 · Ryan Milton🇺🇸 · Sebastián Morán🇺🇸 · Barak Schmookler🇺🇸 · Miguel Arratia🇺🇸

   Key measurements at the future Electron-Ion Collider (EIC), including first-of-their-kind studies of kaon structure, require the detection of ${\Lambda }^0$ at forward angles. We present a feasibility study of ${\Lambda }^0\to n{\pi }^0$ measurements using a high-granularity Zero Degree Calorimeter to be located about 35 m from the interaction point. We introduce a method to address the unprecedented challenge of identifying ${\Lambda }^0$s with energy $O(100)$ GeV that produce displaced vertices of $O(10)$ m. In addition, we present a reconstruction approach using graph neural networks. We find that the energy and angle resolution for ${\Lambda }^0$ is similar to that for neutrons, both of which meet the requirements outlined in the EIC Yellow Report.Furthermore, we estimate performance for measuring the neutron's direction in the ${\Lambda }^0$ rest frame, which reflects the ${\Lambda }^0$ spin polarization. We estimate that the neutral-decay channel ${\Lambda }^0\to n{\pi }^0$ will greatly extend the measurable energy range for the charged-decay channel ${\Lambda }^0\to p{\pi }^{-}$, which is limited by the location of small-angle trackers and the accelerator magnets. This work paves the way for EIC studies of kaon structure and spin phenomena.

   nucl-exPRD(2025)·2 citations
2. 02*

   Recent ALICE results relevant for PDFs at low and high-$x$, saturation

   Anisa Khatun (for the ALICE Collaboration)🇺🇸

   We present recent results from the ALICE Collaboration on the study of coherent and incoherent J/$\psi$ photoproduction in ultra-peripheral Pb-Pb collisions, including results from exclusive and dissociate J/$\psi$ mesons in ultra-peripheral p-Pb interactions. These measurements provide unique insights into the initial state of protons and ions, with great sensitivity for both gluon saturation and shadowing. Furthermore, we will discuss the prospects for these measurements using the Run 3 and Run 4 data.

   nucl-exhep-exActa Phys.Polon.Supp.(2025)·0 citations
3. 03*

   Laser-Induced Quenching of the Th-229 Nuclear Clock Isomer in Calcium Fluoride

   F. Schaden🇦🇹 · T. Riebner🇦🇹 · I. Morawetz🇦🇹 · L. Toscani De Col🇦🇹 · G.A. Kazakov🇦🇹 · K. Beeks🇦🇹 · T. Sikorsky · T. Schumm🇦🇹 · K. Zhang🇩🇪 · V. Lal🇩🇪 · G. Zitzer🇩🇪 · J. Tiedau🇩🇪 · M.V. Okhapkin🇩🇪 · E. Peik🇩🇪

   The 10-minute radiative lifetime of the first excited ${}^{229}$Th${}^{4+}$ nuclear state in ionic crystals provides narrow spectroscopic linewidths, enabling the realization of a solid-state nuclear clock. Due to the 4+ noble gas configuration, electronic readout or state initialization schemes known from atomic clocks are inaccessible. This elongates the interrogation cycle, which will deteriorate the clock performance. To address this limitation we demonstrate laser-induced quenching (LIQ) as a method of depumping the ${}^{229}$Th isomer population in CaF${}_2$. We provide experimental evidence for LIQ at different wavelengths (148 - 420 nm) and temperatures (100 - 350 K), achieving a threefold reduction in the isomer lifetime with 20 mW of laser power.

   ↳ physics.atom-phcond-mat.othernucl-exquant-phPRResearch(2025)·22 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.