Fri·Sep 26, 2025Friday·September 26, 2025

1. 01*

   Lifetimes of the $2_1^{+}$ and $4_1^{+}$ states of the neutron-rich nuclide ${}^{200}$Pt

   C. M. Nickel🇩🇪 · V. Werner🇩🇪 · P. R. John🇮🇹 · U. Ahmed🇩🇪 · T. Beck · M. Boromiza🇷🇴 · C. Clisu-Stan · A. Coman · C. Costache🇷🇴 · N. M. Florea · K. E. Ide🇯🇵 · A. Ionescu and 15 other authors

   The lifetimes of the $2_1^{+}$ and $4_1^{+}$ states of ${}^{200}$Pt were measured applying the recoil-distance Doppler-shift method. Excited states were populated in the ${}^{198}$Pt(${}^{18}$O, ${}^{16}$O)${}^{200}$Pt two-neutron transfer reaction at the $9\text{MV}$ tandem accelerator at the IFIN-HH in Măgurele, Romania. The resulting $B(E2)$ values of the $2_1^{+}\to 0_1^{+}$ and $4_1^{+}\to 2_1^{+}$ transitions as well as the $B_{4/2}$ ratio of $2.08(32)$ indicate the nuclear structure evolving towards sphericity when approaching the neutron shell closure at $N=126$. The $B(E2;2_1^{+}\to 0_1^{+})$ values of Pt and Hg are compared to values of Te, Xe and Ba as both regions of the nuclear chart show similar structural effects.

   nucl-exPRC(2026)·0 citations
2. 02*

   First results from LEGEND-200 on the search for neutrinoless double beta decay

   Giovanna Saleh (on behalf of the LEGEND Collaboration)🇮🇹

   Neutrinoless double beta decay ($0\nu \beta \beta$) is a rare process which could take place if neutrinos are Majorana fermions: the observation of this decay would provide unambiguous evidence for the existence of new Physics beyond the Standard Model, as it entails a two-units lepton number violation. The LEGEND experiment (Large Enriched Germanium Experiment for Neutrinoless $\beta \beta$ Decay) searches for the $0\nu \beta \beta$ of ${}^{76}$Ge using High Purity Germanium detectors enriched in ${}^{76}$Ge beyond the 86%. The LEGEND project foresees two phases, LEGEND-200, aiming at a final 3$\sigma$ discovery sensitivity beyond 10${}^{27}$ yr, and LEGEND-1000, aiming at a final sensitivity beyond 10${}^{28}$ yr. LEGEND-200 started taking data in 2023 at Laboratori Nazionali del Gran Sasso (LNGS): in about one year it collected a total physics exposure of 61 kg yr, with a background index of $0.5_{-0.2}^{+0.3}\cdot 10^{-3}$ counts/(keV kg yr) in the so-called "golden dataset" and of $1.3_{-0.5}^{+0.8}\cdot 10^{-3}$ counts/(keV kg yr) in the so-called "silver dataset". The performed statistical analysis finds no evidence for a $0\nu \beta \beta$ signal and sets a lower limit on its half life to $T_{1/2}^{0\nu }>0.5\cdot 10^{26}$ yr at 90% CL. A combined analysis of the three germanium-based $0\nu \beta \beta$ experiments GERDA, MAJORANA Demonstrator and LEGEND-200 provides a lower limit of $T_{1/2}^{0\nu }>1.9\cdot 10^{26}$ yr at 90% CL.

   nucl-exhep-exNuovo Cim.C(2026)·2 citations
3. 03*

   Investigating the Event-Shape Methods in Search for the Chiral Magnetic Effect in Relativistic heavy-ion Collisions

   Han-Sheng Li🇺🇸 · Yicheng Feng🇺🇸 · Fuqiang Wang🇺🇸

   The azimuthal correlator $\Delta \gamma$ searching for the chiral magnetic effect (CME) is contaminated by a major background proportional to the elliptic flow $v_2$. Event-shape engineering (ESE) and event-shape selection (ESS) binning events in {\em dynamical} and {\em statistical} fluctuations of $v_2$, respectively, are two methods searching for the CME. We conduct a systematic study using physics and toy model simulations. It is found that ESE fulfills the general premise of measuring the CME but is statistically hungry, whereas ESS is not practical to measure the CME because of the intertwining variables used in the method.

   nucl-exEPJ Web Conf.(2026)·1 citation
4. 04*

   Effects of mean-field momentum dependence on pion production in intermediate-energy heavy-ion collisions

   Xin Li🇨🇳 · Si-Pei Wang🇨🇳 · Zhen Zhang🇨🇳 · Rui Wang🇨🇳 · Jie Pu🇨🇳 · Chun-Wang Ma🇨🇳 · Lie-Wen Chen🇨🇳

   Pion production in heavy-ion collisions at intermediate energies provides an important probe of the collision dynamics and nuclear matter equation of state, especially the high-density behavior of the symmetry energy. Using the lattice Boltzmann-Uehling-Uhlenbeck transport model with a recently developed nuclear effective interaction based on the so-called N$5$LO Skyrme pseudopotential, we investigate the effects of the momentum dependence of nucleon mean-field potentials on the pion production in Au+Au collisions at a beam energy of $1.23$~GeV/nucleon. We find that a stronger momentum dependence, for which the nucleon mean-field potentials increase faster with momentum, generally suppresses pion production. This feature can be understood in terms of the mean-field-induced modification of nucleon high-momentum phase space during the compression stage: a stronger momentum dependence can reduce the relative fraction of high-momentum nucleons in heavy-ion collisions, thereby suppressing the production of $\Delta$ resonances and pions.

   ↳ nucl-thhep-phnucl-exPLB(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.