Tue·Oct 21, 2025Tuesday·October 21, 2025

1. 01*

   Energy-energy correlators in jets across collision systems and parton flavors

   Anjali Nambrath (for the ALICE Collaboration)🇺🇸

   The two-point energy-energy correlator (EEC) is a novel jet substructure observable probing the correlation of energy flow within jets. In these proceedings, three EEC measurements performed by the ALICE Collaboration are reported. First is a finalized measurement in proton-proton collisions, where the angular dependence of the EEC cross-section shows a separation of the perturbative and non-perturbative regimes. The first EEC measurement is reported in heavy-flavor jets, tagged via a fully-reconstructed D${}^0$ meson. Here, comparison to inclusive pp jets provides insights into the flavor dynamics of QCD fragmentation and hadronization. Finally, the first measurement of EECs in p-Pb collisions is presented. By comparing the results to pp, modifications in jet evolution caused by the presence of a cold nuclear medium can be studied.

   nucl-exEPJ Web Conf.(2025)·6 citations
2. 02*

   Characterization of the ionization response of argon to nuclear recoils at the keV scale with the ReD experiment

   P. Agnes🇮🇹 · I. Ahmad🇵🇱 · S. Albergo🇮🇹 · I. Albuquerque🇧🇷 · M. Atzori Corona🇮🇹 · M. Ave🇮🇹 · B. Bottino🇮🇹 · M. Cadeddu🇮🇹 · A. Caminata🇮🇹 · N. Canci🇮🇹 · M. Caravati🇮🇹 · L. Consiglio🇮🇹 and 33 other authors

   In the recent years, argon-based experiments looking for Dark Matter in the Universe have explored the non-standard scenario in which Dark Matter is made by low-mass Weakly Interacting Massive Particles, of mass in the range of 1-10 GeV instead of the canonical hundreds of GeV. Detecting such particles is challenging, as their expected signatures are nuclear recoils with energies below 10 keV, observable solely via ionization. This necessitates a precise understanding of the detector response in this energy regime, which remains incomplete for argon. To address this, the ReD experiment was developed within the framework of the DarkSide-20k Collaboration to produce and characterize few-keV nuclear recoils. A compact dual-phase argon Time Projection Chamber (TPC) was irradiated with neutrons from a Cf252 source, to produce Ar recoils in the energy range of interest via (n,n') elastic scattering. A downstream spectrometer composed of 18 plastic scintillators detected the neutrons scattered off Ar nuclei, enabling recoil energy reconstruction via two-body kinematics. The ionization yield Qy of argon, defined as the number of electrons produced per unit energy deposit, was measured in a model-independent way between 2 and 10 keV. These measurements extend direct experimental coverage well below the previous limit of approximately 7 keV. The results are consistent with existing data above 7 keV, while they indicate a higher Qy at lower energies.

   nucl-exastro-ph.COhep-exEPJC(2026)·6 citations
3. 03*

   Practical Considerations for Measuring Global Spin Density Matrix Elements of Vector Mesons in Heavy-Ion Collisions

   Gavin Wilks🇺🇸 · Xu Sun🇨🇳 · Zhenyu Ye🇺🇸

   The STAR Collaboration has reported a significant $\varphi$-meson global spin alignment (${\rho }_{00}$) signal in Au+Au collisions at $\sqrt{s_{NN}}\le 62$ GeV by measuring the polar angle distribution of $\varphi$-meson daughters with respect to the orbital angular momentum (OAM) direction of the collision system. In this paper, a new method is explored for studying vector-meson global spin alignment in heavy-ion collisions by examining the two dimensional polar and azimuthal angle distribution. This method allows simultaneous extraction of ${\rho }_{00}$ and off-diagonal spin density matrix elements (SDMEs), providing unique access to local quark-antiquark spin correlations and spin hydrodynamics in quark-gluon plasma (QGP). The new 2D method also removes potential biases from non-zero off-diagonal SDMEs on ${\rho }_{00}$ with the 1D method. A detailed procedure to correct for detector acceptance and resolution effects is also presented and validated by simulation studies.

   nucl-exnucl-thPRC(2026)·0 citations
4. 04*

   Symmetry restoration in the axially deformed proton-neutron quasiparticle random phase approximation for nuclear beta decay: The effect of angular-momentum projection

   R. N. Chen🇨🇳 · Y. N. Zhang🇨🇳 · J. M. Yao🇨🇳 · J. Engel🇺🇸

   We examine the effects of symmetry restoration on nuclear beta decay within the axially deformed proton-neutron quasiparticle random phase approximation (QRPA). We employ the proton-neutron finite-amplitude method (pnFAM) to compute transition amplitudes, and perform angular-momentum projection both after variation and after the QRPA to restore rotational symmetry. Exact projection reduces the calculated beta decay half-lives from those that use the needle approximation by up to 60%, and even more when taking the effects of projection on the ground-state energy into account.

   ↳ nucl-thnucl-exPRC(2026)·1 citation
5. 05*

   Probing the shape evolution and shell structures in neutron-rich N=50 nuclei

   Anil Kumar · Noritaka Shimizu🇯🇵 · Takayuki Miyagi🇩🇪 · Yusuke Tsunoda🇯🇵 · Yutaka Utsuno🇯🇵

   The structure of low-lying states of $N=50$ nuclei is investigated by the advanced Monte Carlo shell model (MCSM) in the $\pi (fp)$-$\nu (sdg)$ model space. We have employed the shell-model Hamiltonian based on the valence-space in-medium similarity renormalization group, with minimal phenomenological adjustments to the single-particle energies. The MCSM results with the modified Hamiltonian nicely predict the shape coexistence of ${}^{78}$Ni, consistent with recent experimental data. The evolution of intrinsic shapes from the spherical shape to prolate shapes in the ground state of $N=50$ nuclei is discussed using the "T-plot" and effective single-particle energies, which visualize the intrinsic quadrupole deformation of the MCSM wave function. The present result shows that the monopole part of the tensor force does not enhance the shape coexistence of ${}^{78}$Ni, unlike the case of ${}^{68}$Ni.

   ↳ nucl-thnucl-exPLB(2026)·3 citations
6. 06*

   Possibility To Study Photon Scattering By Proton In The Reaction e+p -> e+p+gamma

   A.I. Lvov🇷🇺 · V.A. Petrunkin🇷🇺 · S.G. Popov🇷🇺 · B.B. Wojtsekhowski🇺🇸

   A theoretical possibility to determine the proton Compton scattering cross section from the reaction $ep\to ep\gamma$ is studied in the kinematics with a small transversal momentum transfer in the electron leg. With the exception of the region of forward photon directions and extreme photon energies close to the maximum ones or zero, registration of the particles $\gamma$ and $p$ in the final state can enable one to distinguish the sub-process of the Compton scattering from the electron bremsstrahlung background and, owing to complete kinematical reconstruction of each individual event, measure in detail energy and angular dependence of the $\gamma p$-scattering cross section. The count rate expected with a storage ring like NEP having luminosity $L\approx 2\cdot 10^{35}$ cm${}^{-2}\cdot$ sec${}^{-1}$ as projected is $\approx 10^3$ events/hour. Such measurements might help to determine proton polarizabilities with high statistical accuracy.

   ↳ hep-phnucl-ex0 citations
7. 07*

   Activities of the Korea ALICE group for the development and production of the next-generation silicon tracker

   Sanghoon Lim (for the ALICE Collaboration)🇰🇷

   ALICE 3 is the proposed next-generation heavy-ion experiment at the CERN Large Hadron Collider (LHC), envisioned for operation during Run 5. The tracking system of ALICE 3 will consist of a high-precision vertex detector integrated into a retractable structure inside the beam pipe, complemented by a large-area outer tracker covering a broad pseudorapidity range. Both systems will be based on the Monolithic Active Pixel Sensor (MAPS) technology, building upon the developments realized for the recently upgraded ALICE Inner Tracking System (ITS2) and the future ITS3 upgrade. The total silicon area of the ALICE 3 tracking system is expected to be approximately five times larger than that of ITS2, presenting significant challenges in terms of large-scale sensor testing and module production. To address these challenges, research and development activities have been initiated in Korea, including the adaptation of an automated die-attach machine, commonly used in the semiconductor packaging industry, for efficient sensor-to-substrate assembly. This contribution presents the ongoing efforts of the Korea ALICE group toward the development and production of the ALICE 3 silicon tracker. The scope includes sensor evaluation, automated assembly techniques, and prototype module construction, with the aim of establishing scalable procedures for future mass production.

   ↳ physics.ins-detnucl-exEPJ Web Conf.(2026)·0 citations
8. 08*

   Leptonic first-row correlation and unitarity waiting for further JUNO tests

   Zhi-zhong Xing🇨🇳

   We conjecture that there exists a remarkable correlation among the three elements in the first row of the $3\times 3$ lepton flavor mixing matrix $U$: $|U_{e1}^{}{|}^2=2\left(|U_{e2}^{}{|}^2+|U_{e3}^{}{|}^2\right)$, which holds even though $U$ is non-unitary in the canonical seesaw mechanism. This ``first-row correlation" is fully consistent with ${\sin }^2{\theta }_{12}^{}=\left(1-2{\tan }^2{\theta }_{13}^{}\right)/3$ in the unitarity limit of $U$, as supported by the latest JUNO and Daya Bay precision measurements at a confidence level close to $1\sigma$.

   ↳ hep-phhep-exnucl-exSci.Bull.(2026)·9 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.