Tue·Feb 6, 2024Tuesday·February 6, 2024

1. 01*

   Temperature Measurement of Quark-Gluon Plasma at Different Stages

   STAR Collaboration

   In a Quark-Gluon Plasma (QGP), the fundamental building blocks of matter, quarks and gluons, are under extreme conditions of temperature and density. A QGP could exist in the early stages of the Universe, and in various objects and events in the cosmos. The thermodynamic and hydrodynamic properties of the QGP are described by Quantum Chromodynamics (QCD) and can be studied in heavy-ion collisions. Despite being a key thermodynamic parameter, the QGP temperature is still poorly known. Thermal lepton pairs ($e^{+}{e}^{-}$ and ${\mu }^{+}{\mu }^{-}$) are ideal penetrating probes of the true temperature of the emitting source, since their invariant-mass spectra suffer neither from strong final-state interactions nor from blue-shift effects due to rapid expansion. Here we measure the QGP temperature using thermal $e^{+}{e}^{-}$ production at the Relativistic Heavy Ion Collider (RHIC). The average temperature from the low-mass region (in-medium ${\rho }^0$ vector-meson dominant) is $(1.99\pm 0.24)\times 10^{12}$ K, consistent with the chemical freeze-out temperature from statistical models and the phase transition temperature from LQCD. The average temperature from the intermediate mass region (above the ${\rho }^0$ mass, QGP dominant) is significantly higher at $(3.40\pm 0.55)\times 10^{12}$ K. This work provides essential experimental thermodynamic measurements to map out the QCD phase diagram and understand the properties of matter under extreme conditions.

   nucl-exhep-exhep-phNature Commun.(2025)·49 citations
2. 02*

   Determination of the spins and parities for the 0${}_4^{+}$ and 0${}_5^{+}$ states in ${}^{100}$Zr

   J. Wu · M.P. Carpenter🇺🇸 · F.G. Kondev · R.V.F. Janssens🇺🇸 · S. Zhu🇨🇳 · E.A. McCutchan🇺🇸 · A.D. Ayangeakaa🇺🇸 · J. Chen🇨🇳 · J. Clark🇺🇸 · D. J. Hartley · T. Lauritsen🇺🇸 · N. Pietralla🇩🇪 and 3 other authors

   Two 0${}^{+}$ states at 1294.5 and 1774.0 keV, together with three 2${}^{+}$ and one 4${}^{+}$ levels, were identified or unambiguously spin-parity assigned for the first time in ${}^{100}$Zr utilizing $\gamma$-ray spectroscopy and $\gamma$-$\gamma$ angular correlation techniques with the Gammasphere spectrometer, following the ${\beta }^{-}$ decay of neutron-rich, mass separated ${}^{100,100m}$Y isotopes. Comparisons with recent Monte Carlo Shell-Model (MCSM) calculations indicate that these two states are candidates for the bandhead of a sequence in a shape-coexisting spherical minimum predicted to be located around $\approx$1500 keV. According to the measured relative B(E2)${}_{relative}$ transition probabilities, the 0${}_5^{+}$ state exhibits decay properties which more closely align with those predicted for a spherical shape, while the 0${}_4^{+}$ level is suggested to be associated with a weakly-deformed shape similar to one related to the 0${}_2^{+}$ state.

   nucl-exPRC(2024)·6 citations
3. 03*

   The nonflow issue in connecting anisotropy measurements to hydrodynamics in relativistic heavy-ion collisions

   Fuqiang Wang🇺🇸

   Hydrodynamics can describe majority of the measured azimuthal anisotropies in relativistic heavy-ion collisions. Many of the anisotropy measurements are contaminated by nonflow correlations (i.e., those unrelated to global event-wise correlations). Those nonflow contamination can cause incorrectness or compromise the accuracy of the physics extracted from data-hydrodynamics comparison, particularly when one relies on subtle difference in the measurements. In the recent preprint by STAR (arXiv:2401.06625) extracting the Uranium nucleus deformation parameter, nonflow contamination is assessed by subevents in the limited STAR acceptance. In this note, we demonstrate that such assessment is inadequate and illustrate how large an effect nonflow can cause by using the HIJING model, in which all correlations are nonflow and non-hydrodynamic. We thereby conclude that the extracted Uranium deformation parameter is premature and emphasize the importance of an earnest assessment of or correction for nonflow contamination, not only for this STAR analysis but more generally for studies relying on comparing anisotropy measurements to hydrodynamic calculations.

   nucl-exhep-exhep-phnucl-th3 citations
4. 04*

   Design, Construction, and Performance of the GEM based Radial Time Projection Chamber for the BONuS12 Experiment with CLAS12

   I. Albayrak🇺🇸 · S. Aune🇫🇷 · C. Ayerbe Gayoso🇺🇸 · P. Baron🇫🇷 · S. Bültmann🇺🇸 · G. Charles🇺🇸 · M. E. Christy🇺🇸 · G. Dodge🇺🇸 · N. Dzbenski🇺🇸 · R. Dupré🇫🇷 · K. Griffioen🇺🇸 · M. Hattawy🇺🇸 and 12 other authors

   A new radial time projection chamber based on Gas Electron Multiplier amplification layers was developed for the BONuS12 experiment in Hall B at Jefferson Lab. This device represents a significant evolutionary development over similar devices constructed for previous experiments, including cylindrical amplification layers constructed from single continuous GEM foils with less than 1\% dead area. Particular attention had been paid to producing excellent geometric uniformity of all electrodes, including the very thin metalized polyester film of the cylindrical cathode. This manuscript describes the design, construction, and performance of this new detector.

   ↳ physics.ins-dethep-exnucl-exNucl.Instrum.Meth.A(2024)·6 citations
5. 05*

   Ab initio description of monopole resonances in light- and medium-mass nuclei: I. Technical aspects and uncertainties of ab initio PGCM calculations

   Andrea Porro🇩🇪 · Thomas Duguet🇫🇷 · Jean-Paul Ebran🇫🇷 · Mikael Frosini🇫🇷 · Robert Roth🇩🇪 · Vittorio Somá🇫🇷

   Giant resonances (GRs) are a striking manifestation of collective motions in mesoscopic systems such as atomic nuclei. Until recently, theoretical investigations have essentially relied on the (quasiparticle) random phase approximation ((Q)RPA), and extensions of it, based on phenomenological energy density functionals (EDFs). As part of a current effort to describe GRs within an ab initio theoretical scheme, the present work promotes the use of the projected generator coordinate method (PGCM). This method, which can handle anharmonic effects while satisfying symmetries of the nuclear Hamiltonian, displays a favorable (i.e. mean-field-like) scaling with system's size. Presently focusing on the isoscalar giant monopole resonance (GMR) of light- and medium-mass nuclei, PGCM's potential to deliver wide-range ab initio studies of GRs in closed- and open-shell nuclei encompassing pairing, deformation, and shape coexistence effects is demonstrated. The comparison with consistent QRPA calculations highlights PGCM's unique attributes and sheds light on the intricate interplay of nuclear collective excitations. The present paper is the first in a series of four and focuses on technical aspects and uncertainty quantification of ab initio PGCM calculations of GMR using the doubly open-shell ${}^{46}$Ti as an illustrative example. The second paper displays results for a set of nuclei of physical interest and proceeds to the comparison with consistent (deformed) ab initio QRPA calculations. While the third paper analyzes useful moments of the monopolar strength function and different ways to access them within PGCM calculations, the fourth paper focuses on the effect of the symmetry restoration on the monopole strength function.

   ↳ nucl-thnucl-exEPJA(2024)·17 citations
6. 06*

   System size and shape dependences of collective flow fluctuations in relativistic nuclear collisions

   Xinrong Chen🇨🇳 · Xiang-Yu Wu🇨🇦 · Shanshan Cao🇨🇳 · Guang-You Qin🇨🇳

   Quantum fluctuations plays an essential role in forming the collective flow of hadrons observed in relativistic heavy-ion collisions. Event-by-event fluctuations of the collective flow can arise from various sources, such as the fluctuations in the initial geometry, hydrodynamic expansion, hadronization, and hadronic evolution of the nuclear matter, while the exact contribution from each source is still an open question. Using a (3+1)-dimensional relativistic hydrodynamic model coupled to a Monte-Carlo Glauber initial condition, Cooper-Frye particlization and a hadronic transport model, we explore the system size and shape dependences of the collective flow fluctuations in Au+Au, Cu+Au, and O+O collisions at $\sqrt{s_{\mathrm{NN}}}=200$~GeV. The particle yields, mean transverse momenta, 2-particle and 4-particle cumulant elliptic flows ($v_2\{2\}$ and $v_2\{4\}$) from our calculation agree with the currently existing data from RHIC. Different centrality dependences of the flow fluctuations, quantified by the $v_2\{4\}/v_2\{2\}$ ratio, are found for different collision systems due to their different sizes and shapes. By comparing $v_2\{4\}/v_2\{2\}$ between different hadron species, and comparing $v_2\{4\}/v_2\{2\}$ to the initial state geometric fluctuations quantified by the cumulant eccentricity ratio ${\epsilon }_2\{4\}/{\epsilon }_2\{2\}$, we find that while the initial state fluctuations are the main source of the $v_2$ fluctuations in large collision systems, other sources like nonlinear hydrodynamic response, hadronization, and hadronic afterburner can significantly affect the $v_2$ fluctuations in small systems.

   ↳ nucl-thhep-phnucl-exPRC(2024)·4 citations
7. 07*

   Constraining kaon PDFs from Drell-Yan and $J/\psi$ production

   Wen-Chen Chang🇹🇼 · Jen-Chieh Peng🇺🇸 · Stephane Platchkov🇫🇷 · Takahiro Sawada🇺🇸

   The kaon parton distribution functions (PDFs) are poorly known due to paucity of kaon-induced Drell-Yan data. Nevertheless, these Drell-Yan data suggest a softer valence $u$ quark distribution of kaon than that of pion. We discuss the opportunity to constrain kaon PDFs utilizing existing kaon-induced $J/\psi$ production data. We compare the $K^{-}/{\pi }^{-}$ and $K^{+}/{\pi }^{+}$ cross-section ratio data with calculations based on two global-fit parametrizations and two recent theoretical predictions for the kaon and pion PDFs, and test the results with two quarkonium production models. The $K^{-}/{\pi }^{-}$ cross-section ratio for $J/\psi$ production provides independent evidence of different valence quark distributions in pion and kaon. The $K^{+}/{\pi }^{+}$ $J/\psi$ data are found to be sensitive to the gluon distribution in kaon. We show that these $J/\psi$ production data provide valuable constraints for evaluating the adequacy of currently available sets of kaon PDFs.

   ↳ hep-phhep-exnucl-exnucl-thPLB(2024)·10 citations
8. 08*

   Nuclear mass table in deformed relativistic Hartree-Bogoliubov theory in continuum, II: Even-$Z$ nuclei

   DRHBc Mass Table Collaboration: Peng Guo · Xiaojie Cao🇨🇳 · Kangmin Chen🇨🇳 · Zhihui Chen🇨🇳 · Myung-Ki Cheoun🇰🇷 · Yong-Beom Choi🇰🇷 · Pak Chung Lam · Wenmin Deng · Jianmin Dong🇨🇳 · Pengxiang Du · Xiaokai Du🇨🇳 · Kangda Duan🇨🇳 and 70 other authors

   The mass table in the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc) with the PC-PK1 density functional has been established for even-$Z$ nuclei with $8\le Z\le 120$, extended from the previous work for even-even nuclei [Zhang $et.al.$ (DRHBc Mass Table Collaboration), At. Data Nucl. Data Tables 144, 101488 (2022)]. The calculated binding energies, two-nucleon and one-neutron separation energies, root-mean-square (rms) radii of neutron, proton, matter, and charge distributions, quadrupole deformations, and neutron and proton Fermi surfaces are tabulated and compared with available experimental data. A total of 4829 even-$Z$ nuclei are predicted to be bound, with an rms deviation of 1.477 MeV from the 1244 mass data. Good agreement with the available experimental odd-even mass differences, $\alpha$ decay energies, and charge radii is also achieved. The description accuracy for nuclear masses and nucleon separation energies as well as the prediction for drip lines is compared with the results obtained from other relativistic and nonrelativistic density functional. The comparison shows that the DRHBc theory with PC-PK1 provides an excellent microscopic description for the masses of even-$Z$ nuclei. The systematics of the nucleon separation energies, odd-even mass differences, pairing energies, two-nucleon gaps, $\alpha$ decay energies, rms radii, quadrupole deformations, potential energy curves, neutron density distributions, and neutron mean-field potentials are discussed.

   ↳ nucl-thastro-ph.SRnucl-exAtom.Data Nucl.Data Tabl.(2024)·95 citations
9. 09*

   Synchronous Detection of Cosmic Rays and Correlated Errors in Superconducting Qubit Arrays

   Patrick M. Harrington🇺🇸 · Mingyu Li🇺🇸 · Max Hays🇬🇧 · Wouter Van De Pontseele🇺🇸 · Daniel Mayer🇺🇸 · H. Douglas Pinckney🇺🇸 · Felipe Contipelli🇺🇸 · Michael Gingras🇺🇸 · Bethany M. Niedzielski🇺🇸 · Hannah Stickler🇺🇸 · Jonilyn L. Yoder🇺🇸 · Mollie E. Schwartz🇺🇸 and 4 other authors

   Quantum information processing at scale will require sufficiently stable and long-lived qubits, likely enabled by error-correction codes. Several recent superconducting-qubit experiments, however, reported observing intermittent spatiotemporally correlated errors that would be problematic for conventional codes, with ionizing radiation being a likely cause. Here, we directly measured the cosmic-ray contribution to spatiotemporally correlated qubit errors. We accomplished this by synchronously monitoring cosmic-ray detectors and qubit energy-relaxation dynamics of 10 transmon qubits distributed across a 5x5x0.35 mm${}^3$ silicon chip. Cosmic rays caused correlated errors at a rate of 1/(10 min), accounting for 17$\pm$1% of all such events. Our qubits responded to essentially all of the cosmic rays and their secondary particles incident on the chip, consistent with the independently measured arrival flux. Moreover, we observed that the landscape of the superconducting gap in proximity to the Josephson junctions dramatically impacts the qubit response to cosmic rays. Given the practical difficulties associated with shielding cosmic rays, our results indicate the importance of radiation hardening -- for example, superconducting gap engineering -- to the realization of robust quantum error correction.

   ↳ quant-phhep-exnucl-exphysics.ins-detNature Commun.(2025)·69 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.