Mon·Nov 3, 2025Monday·November 3, 2025

1. 01*

   First evidence for the J$>$1 components of the pygmy dipole resonance in neutron-rich nuclei

   R. Li🇫🇷 · E. Litvinova🇺🇸 · M. N. Harakeh🇳🇱 · D. Verney🇫🇷 · I. Matea🇫🇷 · L. Al Ayoubi🇫🇷 · H. Al Falou🇱🇧 · P. Bednarczyk🇵🇱 · G. Benzoni🇮🇹 · V. Bozkurt🇹🇷 · A. Bracco🇮🇹 · M. Ciemała🇵🇱 and 12 other authors

   Gamma ($\gamma$) decay shapes the synthesis of heavy elements in neutron-rich nuclear environments of neutron star mergers, supplying the Universe with heavy elements. The low-energy pygmy dipole resonance (PDR) influences nuclear reaction rates of the rapid nucleosynthesis through enhanced $\gamma$ transitions. However, since it is difficult to reproduce astrophysical conditions in laboratories, PDR was previously observed only in $J=1$ spin states. Here we report the first experimental observation of $J>1$ components of PDR, identified in the $\beta$-delayed $\gamma$ decay of the J${}^{\pi }$ = 3${}^{-}$ spin-parity isomer of ${}^{80}$Ga. The data analysis, combined with decay information and theoretical calculations allows the identification of resonant structures below the neutron emission threshold of the neutron-rich germanium ${}^{80}$Ge as J${}^{\pi }=(2,3{)}^{-}$ components of the PDR built on the low-lying J${}^{\pi }$ = 2${}^{+}$ quadrupole state. Our findings extend the concept of PDR beyond dipole states, with implications for nuclear structure theory and experiment, as well as the element production in the cosmos.

   nucl-exastro-ph.SRnucl-th0 citations
2. 02*

   Muon veto system for the CROSS double-beta decay search experiment

   A.S. Barabash🇷🇺 · L. Bergé🇫🇷 · M. Buchynska🇫🇷 · J.M. Calvo-Mozota🇪🇸 · A. Candela🇮🇹 · P. Carniti🇮🇹 · M. Chapellier🇫🇷 · D. Cintas🇫🇷 · A. Corsi🇫🇷 · I. Dafinei🇮🇹 · F.A. Danevich🇺🇦 · M. De Deo🇮🇹 and 27 other authors

   In preparation to the CROSS experiment at the Canfranc underground laboratory (Spain) $-$ aiming to search for neutrinoless double-beta ($0\nu \beta \beta$) decay of ${}^{100}$Mo using low-temperature detectors with heat-scintillation readout $-$ we report on development of a dedicated muon veto system. The need for the muon veto in CROSS is caused by a comparatively high residual cosmic muon flux at the experimental site ($\sim$20 $\mu$/m${}^2$/h), being a dominant background in the region of interest (ROI) at $\sim$3 MeV. Thus, we installed the muon veto system around the CROSS low-background setup, forming four lateral, one top, and four bottom sectors. In this paper we describe the design, construction and operation of the CROSS muon veto system, as well as its optimization and validation by comparing dedicated Monte Carlo (MC) simulations of muons with low-temperature measurements in the setup. We demonstrate a stable operation of the veto system with the average trigger rates compatible with MC simulations. Also, we investigated two muon trigger logics based on coincidences with either 2 sectors or a single sector of the veto. The MC study shows that, in combination with the multiplicity cut of thermal detectors, these trigger logics allow to reject 99.2\% and 99.7\% of muon-induced events in the ROI, respectively. Despite a comparatively high dead time ($\sim$18\%) introduced by coincidences with any of nine sectors of the veto $-$ the adopted strategy $-$ the muon-induced background in the ROI of the CROSS experiment can be reduced down to $\sim$2 $\times 10^{-3}$ cnts/keV/kg/yr, i.e., an acceptable level compatible with a high-sensitivity $0\nu \beta \beta$ decay search foreseen in CROSS.

   ↳ physics.ins-dethep-exnucl-exJINST(2026)·1 citation
3. 03*

   Improved phenomenology of $\pi N$ transition distribution amplitudes

   Bernard Pire🇫🇷 · Kirill Semenov-Tian-Shansky🇰🇷 · Paweł Sznajder🇵🇱 · Lech Szymanowski🇵🇱

   To study cross sections and polarization asymmetries for the processes $ep\to en{\pi }^{+}$ and $ep\to ep{\pi }^0$ in the backward region, we develop a flexible phenomenological model for nucleon-to-pion transition distribution amplitudes ($\pi N$ TDAs), which are used in the QCD collinear factorization description of the scattering amplitudes. Our model is based on the two-component factorized Ansatz for the corresponding spectral densities, quadruple distribution. It takes into account the constraints for $\pi N$ TDAs arising from the threshold pion production theorem and also includes a forward limit contribution that can be fitted to experimental data. We examine the sensitivity of observable predictions to various modelling assumptions.

   ↳ hep-phhep-exnucl-exnucl-thEPJ Web Conf.(2026)·1 citation
4. 04*

   Energy Correlators from Partons to Hadrons: Unveiling the Dynamics of the Strong Interactions with Archival ALEPH Data

   Hannah Bossi🇺🇸 · Yi Chen🇺🇸 · Yu-Chen Chen🇺🇸 · Max Jaarsma🇳🇱 · Yibei Li🇩🇪 · Jingyu Zhang🇺🇸 · Ian Moult🇺🇸 · Wouter Waalewijn🇳🇱 · Hua Xing Zhu🇨🇳 · Anthony Badea🇺🇸 · Austin Baty🇺🇸 · Christopher McGinn🇺🇸 and 3 other authors

   Quantum Chromodynamics (QCD) is a remarkably rich theory exhibiting numerous emergent degrees of freedom, from flux tubes to hadrons. Their description in terms of the underlying quarks and gluons of the QCD Lagrangian remains a central challenge of modern physics. Colliders offer a unique opportunity to probe these phenomena experimentally: high energy partons produced from the QCD vacuum excite these emergent degrees, imprinting their dynamics in correlations in asymptotic energy flux. Decoding these correlations requires measurements with exceptional angular resolution, beyond that achieved in previous measurements. Recent progress has enabled precision calculations of energy flux on charged particles alone, allowing data-theory comparisons for measurements using high resolution tracking detectors. In this Letter, we resurrect thirty-year-old data from the ALEPH tracker, and perform a high angular resolution measurement of the two-point correlation of energy flux, probing QCD over three orders of magnitude in scale in a single measurement. Our measurement unveils for the first time the full spectrum of the correlator, including light-ray quasi-particle states, flux-tube excitations, and their transitions into confined hadrons. We compare our measurement with record precision theoretical predictions, achieving percent level agreement, and revealing interesting new phenomena in the confinement transitions. More broadly, we highlight the immense potential of this newly unlocked archival data set, the so called "recycling frontier", and emphasize synergies with ongoing and future collider experiments.

   ↳ hep-phhep-exhep-thnucl-ex+133 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.