Wed·Oct 29, 2025Wednesday·October 29, 2025

1. 01*

   Tomographic beta-gamma spectroscopy of nuclear beta decay

   PandaX Collaboration: Zhe Yuan🇨🇳 · Zihao Bo🇨🇳 · Wei Chen🇨🇳 · Xun Chen🇨🇳 · Yunhua Chen🇨🇳 · Chen Cheng🇨🇳 · Xiangyi Cui🇨🇳 · Manna Deng🇨🇳 · Yingjie Fan🇨🇳 · Deqing Fang🇨🇳 · Xuanye Fu🇨🇳 · Zhixing Gao🇨🇳 and 101 other authors

   Nuclear $\beta$ decay, a sensitive probe of nuclear structure and weak interactions, has become a precision test bed for physics beyond the Standard Model, driven by recent advances in spectrometric techniques. Here we introduce tomographic $\beta$-$\gamma$ spectroscopy (TBGS) of nuclear $\beta$ decay, a method that detects the energies of $\beta$, $\gamma$, and internal conversion electrons while simultaneously reconstructing the energy deposition vertices. Using the PandaX-4T detector operated as a TBGS, we obtain a precise and unbiased decay scheme of ${}^{214}$Pb, a key background isotope in searches for dark matter and Majorana neutrinos. For the first time, transitions of ${}^{214}$Pb to both the ground and excited states of ${}^{214}$Bi are measured concurrently, revealing discrepancies in branching ratios of up to 4.7$\sigma$ relative to previous evaluations. Combined with state-of-the-art theoretical spectral-shape calculations, these results establish a new benchmark for background modelling in rare-event searches and highlight the potential of TBGS as a versatile tool for fundamental physics and nuclear applications.

   nucl-exhep-ex1 citation
2. 02*

   Symmetry Constraints on Pion Valence Structure

   Xiaobin Wang🇨🇳 · Lei Chang🇨🇳 · Minghui Ding🇨🇳 · Khepani Raya🇪🇸 · Craig D. Roberts🇨🇳

   The profile of the pion valence quark distribution function (DF) remains controversial. Working from the concepts of QCD effective charges and generalised parton distributions, we show that since the pion elastic electromagnetic form factor is well approximated by a monopole, then, at large light-front momentum fraction, the pion valence quark DF is a convex function described by a large-$x$ power law that is practically consistent with expectations based on quantum chromodynamics.

   ↳ hep-phhep-exhep-latnucl-ex+1Chin.Phys.Lett.(2026)·4 citations
3. 03*

   Emergent Bell-Triplet State in Proton-Proton Scattering

   Z. X. Shen · H. Y. Shang · Y. G. Ma🇨🇳 · D. Bai🇨🇳 · S. M. Wang🇨🇳 · Z. C. Xu🇨🇳 · Y. Ayyad🇪🇸 · C. Filgueira

   Entanglement is a key resource in quantum information science, yet its properties and applications in nuclear systems remain largely unexplored. Here, using proton-proton scattering as a quantum laboratory, we report the emergence of a near-pure Bell-triplet state at a laboratory energy of 151 MeV and a center-of-mass scattering angle of 90 degrees. In this unique kinematic regime, the scattering amplitude functions as a transition operator connecting distinct Bell states. Building upon this emergent resource, we propose a quantum teleportation protocol for proton spins, exploiting the intrinsic Hamiltonian of the strong interaction to perform the requisite Bell measurement. These findings effectively bridge few-body nuclear physics and quantum technology, establishing proton-proton scattering as both a source of high-fidelity entanglement and a natural processor for quantum information.

   ↳ nucl-thnucl-exquant-ph9 citations
4. 04*

   Comprehensive Inclusion of Higher-order Ca${}^{+}$ Isotope Shifts in the King's Plot Yields an Order Improvement on the $e^{-}$-$n$ Coupling Limit

   Vaibhav Katyal🇮🇳 · A. Chakraborty🇮🇳 · B. K. Sahoo🇮🇳

   By critically evaluating higher-order nonlinear effects to the isotope shifts (ISs) in the low-lying transition frequencies of the singly charged calcium ion, stringent constraint on the electron-neutron coupling due to a hypothetical boson describing physics beyond the Standard Model is inferred. It shows an order magnitude difference compared to the previously reported limit demonstrating importance of higher-order effects in the analysis of nonlinearity in the King's plot. The first-order IS parameters and enhancement factor ($D$) were evaluated using two complementary approaches in the relativistic coupled-cluster theory framework: namely finite-field (FF) and analytical response (AR) approaches. Extraction of the second-order IS parameters in the FF approach show numerical instabilities, so they are determined in the AR approach. Comparison of these factors with previous calculation shows substantial differences in the magnitudes. However, $D$ values from both the FF and AR approaches display excellent agreement. We also show explicitly roles of electron correlation effects in the evaluation of $D$ values accurately.

   ↳ physics.atom-phastro-ph.SRhep-phnucl-ex+10 citations
5. 05*

   Heavy Quark Energy Loss in the Hybrid Model

   Andrea Beraudo🇮🇹 · Jean F. Du Plessis🇺🇸 · Daniel Pablos🇪🇸 · Krishna Rajagopal🇺🇸

   Heavy quarks offer an invaluable hard probe of the droplets of quark gluon plasma (QGP) formed in heavy ion collisions at the LHC and RHIC. Given their large mass, they are predominantly produced in hard scattering processes at the earliest moment of a collision and given their rarity they almost never annihilate with a heavy antiquark subsequently. This means that they experience, and probe, the entire history of the expanding, cooling, droplet of QGP from hydrodynamization through hadronization. Quantitative measurements of heavy quark final state observables therefore give us access to information about the transport properties of QGP as well as about medium modifications of hadronization. To date, the Hybrid strong/weak coupling Model of jet quenching has not included any implementation of the heavy-quark sector, which has made it impossible to confront its predictions with measurements of heavy quark and jet observables together, in a unified fashion. Here, we extend the Hybrid Model to investigate heavy quark observables for the first time. We introduce a strongly-coupled calculation of heavy-quark energy loss with the correct behavior when the heavy quarks are either ultrarelativistic or non-relativistic, Gaussian momentum broadening, and recombination of heavy quarks with medium partons using a local color neutralization model of hadronization. We compare our results for the suppression $R_{\mathrm{AA}}$ and azimuthal anisotropies $v_2$ of B- and D-mesons and ${\Lambda }_c$ baryons, the $R_{\mathrm{AA}}$ of B-tagged jets, as well as baryon-to-meson ratios, with available experimental data from ALICE, ATLAS and CMS.

   ↳ hep-phnucl-exnucl-thJHEP(2026)·6 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.