Wed·Sep 18, 2024Wednesday·September 18, 2024

1. 01*

   Investigating baryon-strangeness and charge-strangeness correlations in Pb$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV with ALICE

   Swati Saha (for the ALICE Collaboration)🇮🇳

   To explore the quantum chromodynamics (QCD) phase transitions and the properties of quark$-$gluon plasma, the ALICE collaboration at CERN has conducted an extensive analysis of the correlations among net-conserved quantities, namely net-baryon, net-charge, and net-strangeness. These correlations are essential for understanding the QCD phase structure, as they are directly connected to ratios of thermodynamic susceptibilities calculated in lattice QCD. This analysis focuses on the correlations between net-kaon and net-proton, as well as net-kaon and net-charge, in Pb$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV, where net-proton and net-kaon serve as effective proxies for net-baryon and net-strangeness, respectively. A comparison with theoretical predictions from the Thermal-FIST model sheds light on the role of resonance decays and the effects of charge conservation laws in shaping these correlations. Furthermore, the measurements show sensitivity to the correlation volume in which these conservation laws are applied, underscoring the importance of modeling the underlying dynamics to fully understand the experimental results on fluctuations and correlations in heavy-ion collisions.

   nucl-exhep-exPoS(2025)·0 citations
2. 02*

   Measurement of photonuclear jet production in ultra-peripheral Pb+Pb collisions at $\sqrt{s_{\text{NN}}}=5.02$ TeV with the ATLAS detector

   ATLAS Collaboration

   In ultra-relativistic heavy ion collisions at the LHC, each nucleus acts a sources of high-energy real photons that can scatter off the opposing nucleus in ultra-peripheral photonuclear ($\gamma +A$) collisions. Hard scattering processes initiated by the photons in such collisions provide a novel method for probing nuclear parton distributions in a kinematic region not easily accessible to other measurements. ATLAS has measured production of dijet and multi-jet final states in ultra-peripheral Pb+Pb collisions at $\sqrt{s_{\text{NN}}}=5.02$ TeV using a data set recorded in 2018 with an integrated luminosity of 1.72 ${\text{nb}}^{-1}$. Photonuclear final states are selected by requiring a rapidity gap in the photon direction; this selects events where one of the outgoing nuclei remains intact. Jets are reconstructed using the anti-$k_{\text{t}}$ algorithm with radius parameter, $R=0.4$. Triple-differential cross-sections, unfolded for detector response, are measured and presented using two sets of kinematic variables. The first set consists of the total transverse momentum ($H_{\text{T}}$),rapidity, and mass of the jet system. The second set uses $H_{\text{T}}$ and particle-level nuclear and photon parton momentum fractions, $x_{\text{A}}$ and $z_{\gamma }$, respectively. The results are compared with leading-order (LO) perturbative QCD calculations of photonuclear jet production cross-sections, where all LO predictions using existing fits fall below the data in the shadowing region. More detailed theoretical comparisons will allow these results to strongly constrain nuclear parton distributions, and these data provide results from the LHC directly comparable to early physics results at the planned Electron-Ion Collider.

   nucl-exhep-exPRD(2025)·37 citations
3. 03*

   Ultra-low $Q_{\beta }$ value for the allowed decay of ${}^{110}$Ag${}^m$ confirmed via mass measurements

   J. Ruotsalainen🇫🇮 · M. Stryjczyk🇫🇮 · M. Ramalho🇫🇮 · T. Eronen🇫🇮 · Z. Ge🇫🇮 · A. Kankainen🇫🇮 · M. Mougeot🇫🇮 · J. Suhonen🇫🇮

   The mass of the electron-antineutrino can be determined in dedicated measurements of the $\beta$ spectral shape near the $\beta$ endpoint of a ${\beta }^{-}$ transition, with a low $Q$ value enhancing the sensitivity of the measurement. One such low-$Q$-value candidate is the transition between the $6^{+}$ isomer of ${}^{110}$Ag and the $5_2^{+}$ state in ${}^{110}$Cd ($Q_{\beta ,m}^{\ast }=-0.12(131)$ keV). To reduce the uncertainty of the $Q$ value, we have used the phase-imaging ion-cyclotron-resonance technique with the JYFLTRAP double Penning trap and performed a high-precision atomic-mass measurement of ${}^{109}$Ag with ${}^{110}$Cd as a reference. Combined with the known spectroscopic data, we obtain a re-evaluated value $Q_{\beta ,m}^{\ast }=405(135)$ eV, for the ${}^{110}\text{Ag}(6_{\text{m}}^{+})\to {}^{110}\text{Cd}(5_2^{+})$ transition. This represents the lowest $Q_{\beta }$ value for any allowed transition observed to date. In order to estimate the partial half-life ($t_{1/2}$) and branching ratio (Br) of the transition, nuclear shell-model calculations were performed using the $jj45pnb$ Hamiltonian in combination with state-of-the-art atomic calculations. The computed values $t_{1/2}=2.23_{-1.28}^{+5.24}\times 10^7$ years and $\text{Br}=3.07_{-2.15}^{+4.16}\times 10^{-8}$, along with the thermal-neutron capture on stable ${}^{109}$Ag as a viable production method, make ${}^{110}{\text{Ag}}^m$ a promising candidate for future antineutrino-mass measurements.

   nucl-exnucl-thPRL(2025)·2 citations
4. 04*

   Global Extraction of the ${}^{12}\mathrm{C}$ Nuclear Electromagnetic Response Functions (${\mathcal{R}}_L$ and ${\mathcal{R}}_T$) and Comparisons to Nuclear Theory and Neutrino/Electron Monte Carlo Generators

   Arie Bodek🇺🇸 · M. E. Christy🇺🇸 · Zihao Lin🇺🇸 · Giulia-Maria Bulugean🇺🇸 · Amii Matamoros Delgado🇺🇸 · Artur M. Ankowski🇵🇱 · G. D. Megias🇪🇸 · Julia Tena Vidal🇮🇱

   We have performed a global extraction of the ${}^{12}\mathrm{C}$ longitudinal (${\mathcal{R}}_L$) and transverse (${\mathcal{R}}_T$) nuclear electromagnetic response functions from an analysis of all available electron scattering data on carbon. The response functions are extracted for energy transfer $\nu$, spanning the nuclear excitation, quasielastic (QE), resonance and inelastic continuum over a large range of the square of the four-momentum transfer, $Q^2.$ In addition, we perform a universal fit to all ${}^{12}\mathrm{C}$ electron scattering data which also provides parmeterizations of ${\mathcal{R}}_L$ and ${\mathcal{R}}_T$ over a larger kinematic range. Given the nuclear physics common to both electron and neutrino scattering from nuclei, extracted response functions from electron scattering spanning a large range of $Q^2$ and $\nu$ also provide a powerful tool for validation and tuning of neutrino Monte Carlo (MC) generators. In this paper we focus on the nuclear excitation, single nucleon (QE-1p1h) and two nucleon (2p2h) final state regions and compare the measurements to theoretical predictions including ``Energy Dependent-Relativistic Mean Field'' (ED-RMF), ``Green's Function Monte Carlo'' (GFMC), "Short Time Approximation Quantum Monte Carlo" (STA-QMC), an improved superscaling model (SuSAv2), "Correlated Fermi Gas" (CFG), as well as the \nuwro{}, and \achilles~ generators. Combining the ED-RMF-QE-1p1h predictions with the SuSAv2-MEC-2p2h predictions provides a good description of ${\mathcal{R}}_L$ and ${\mathcal{R}}_T$ for both single nucleon (from QE and nuclear excitations) and two nucleon final states over the entire kinematic range.

   ↳ hep-exnucl-ex6 citations
5. 05*

   Higher forbidden unique ${\beta }^{-}$ decay transitions and shell-model interpretation

   Archana Saxena · Praveen C. Srivastava🇮🇳

   In the present work, we have predicted the half-lives for the ${\beta }^{-}$ decay for higher forbidden unique transitions in the mass range of nuclei from A = 40-138. For these transitions, the experimental data for half-lives are not available except for a few cases. The calculations for half-lives are performed within the framework of the nuclear shell model (SM). We have used the effective interactions sdpf-mu, gxpf1a, gwbxg, G-matrix, snet, sn100pn, and jj56pnb to perform the SM calculations in different mass regions. A comprehensive discussion has been made between the SM-predicted half-lives and the scaled half-lives from proton-neutron quasiparticle random-phase approximation (pnQRPA). The results of the present study will be useful to plan new experiments to measure half-lives for these higher forbidden unique ${\beta }^{-}$ transitions.

   ↳ nucl-thnucl-exNPA(2024)·1 citation

* 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.