Fri·May 26, 2023Friday·May 26, 2023

1. 01*

   Predictions for the sPHENIX physics program

   Ron Belmont🇺🇸 · Jasmine Brewer🇨🇭 · Quinn Brodsky🇺🇸 · Paul Caucal🇫🇷 · Megan Connors🇺🇸 · Magdalena Djordjevic🇷🇸 · Raymond Ehlers🇺🇸 · Miguel A. Escobedo🇪🇸 · Elena G. Ferreiro🇪🇸 · Giuliano Giacalone🇩🇪 · Yoshitaka Hatta🇺🇸 · Jack Holguin🇫🇷 and 16 other authors

   sPHENIX is a next-generation detector experiment at the Relativistic Heavy Ion Collider, designed for a broad set of jet and heavy-flavor probes of the Quark-Gluon Plasma created in heavy ion collisions. In anticipation of the commissioning and first data-taking of the detector in 2023, a RIKEN-BNL Research Center (RBRC) workshop was organized to collect theoretical input and identify compelling aspects of the physics program. This paper compiles theoretical predictions from the workshop participants for jet quenching, heavy flavor and quarkonia, cold QCD, and bulk physics measurements at sPHENIX.

   nucl-exnucl-thNPA(2024)·32 citations
2. 02*

   Latest vertex and tracking detector developments for the future Electron-Ion Collider

   Xuan Li🇺🇸

   The high-luminosity high-energy Electron-Ion Collider (EIC) to be built at Brookhaven National Laboratory (BNL) will provide a clean environment to study several fundamental questions in the high energy and nuclear physics fields. A high granularity and low material budget vertex and tracking detector is required to provide precise measurements of primary and displaced vertex and track reconstruction with good momentum and spatial resolutions. The reference design of the EIC project detector at the first Interaction Point (IP), which was selected from three submitted EIC detector proposals, enables a series of high precision heavy flavor measurements. Based on the EIC project detector reference design, the newly formed ePIC collaboration is developing the technical design for the EIC project detector towards its construction and operation. The reference design of the EIC vertex and tracking detector consists of the Monolithic Active Pixel Sensor (MAPS) based silicon vertex and tracking subsystem, the Micro-Pattern Gas Detector (MPGD) based gas tracking subsystem and the AC-Coupled Low Gain Avalanche Diode (AC-LGAD) based silicon outer tracker, and it has the track reconstruction capability in the pseudorapidity region of -3.5 to 3.5 with full azimuthal coverage. Further detector geometry optimization with a new magnet and technology down selection are underway by the ePIC collaboration. The latest ePIC vertex and tracking detector geometry and its performance evaluated in simulation will be presented. Details of the EIC vertex and tracking detector R$\&$D, which include the proposed detector technologies, prototype sensor characterization and detector mechanical design will be discussed as well.

   ↳ physics.ins-dethep-exnucl-exJPS Conf.Proc.(2024)·1 citation
3. 03*

   The electromagnetic fine-structure constant in primordial nucleosynthesis revisited

   Ulf-G. Meißner🇩🇪 · Bernard Ch. Metsch🇩🇪 · Helen Meyer🇩🇪

   We study the dependence of the primordial nuclear abundances as a function of the electromagnetic fine-structure constant $\alpha$, keeping all other fundamental constants fixed. We update the leading nuclear reaction rates, in particular the electromagnetic contribution to the neutron-proton mass difference pertinent to $\beta$-decays, and go beyond certain approximations made in the literature. In particular, we include the temperature-dependence of the leading nuclear reactions rates and assess the systematic uncertainties by using four different publicly available codes for Big Bang nucleosynthesis. Disregarding the unsolved so-called lithium-problem, we find that the current values for the observationally based ${}^2$H and ${}^4$He abundances restrict the fractional change in the fine-structure constant to less than $2\%$, which is a tighter bound than found in earlier works on the subject.

   ↳ hep-thastro-ph.COhep-phnucl-ex+1EPJA(2023)·23 citations
4. 04*

   Storage, Accumulation and Deceleration of Secondary Beams for Nuclear Astrophysics

   J. Glorius🇩🇪 · Yu. A. Litvinov🇩🇪 · M. Aliotta🇬🇧 · F. Amjad🇩🇪 · B. Brückner🇩🇪 · C.G. Bruno🇬🇧 · R. Chen🇩🇪 · T. Davinson🇬🇧 · S.F. Dellmann🇩🇪 · T. Dickel🇩🇪 · I. Dillmann🇨🇦 · P. Erbacher🇩🇪 and 52 other authors

   Low-energy investigations on rare ion beams are often limited by the available intensity and purity of the ion species in focus. Here, we present the first application of a technique that combines in-flight production at relativistic energies with subsequent secondary beam storage, accumulation and finally deceleration to the energy of interest. Using the FRS and ESR facilities at GSI, this scheme was pioneered to provide a secondary beam of ${}^{118}$Te${}^{52+}$ for the measurement of nuclear proton-capture at energies of 6 and 7 MeV/u. The technique provided stored beam intensities of about $10^6$ ions at high purity and brilliance, representing a major step towards low-energy nuclear physics studies using rare ion beams.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.B(2023)·7 citations
5. 05*

   A study of medium effects in elastic $\pi N$ and $\pi A$ scatterings

   Hyeon-dong Han🇰🇷

   The elastic $\pi N$ scattering is investigated for the $I=3/2$ channel dominated by the $\Delta (1232)$ resonance at finite baryon density, employing the effective Lagrangian approach at the tree-level Born approximation. The quark-meson coupling (QMC) model is employed to describe the in-medium baryon properties that are constructed at the quark level, such as the nucleon and $\Delta$ masses, and $\Delta$ full decay width. I reproduce the experimental data of the cross-section in a vacuum as a justification of our approach and then analyze the in-medium total and differential cross-sections as well as proton-spin asymmetry. Following the results of the in-medium elastic $\pi N$ scattering calculation, the elastic $\pi A$ scattering is investigated at finite baryon density in the framework of the Eikonal Glauber model for the light nuclei, ${}^4\mathrm{He}$ and ${}^{12}\mathrm{C}$. For the description of the finite nuclei, the Wood-Saxon density profile, and an expansion of the charge distribution as a sum of Gaussians are employed in this study. The nuclear density distribution ${\rho }_A$, effective baryon mass $m_B^{\ast }$, in-medium decay width ${\Gamma }_{\Delta }^{\ast }$, and in-medium coupling constants $f_{\pi NN}^{\ast }$ and $f_{\pi N\Delta }^{\ast }$ are analyzed as well as the total cross-section. The results show that the effective baryon mass and cross-sections in the medium decrease as density increases except for the $\Delta$ decay width, which increases as the density increases. The elastic $\pi A$ scattering at the tree-level Born approximation reproduces well the experimental data for ${}^4\mathrm{He}$ but overestimates for ${}^{12}\mathrm{C}$. Results for the in-medium $\Delta$ resonance and other findings in this work will be relevant for the relativistic heavy-ion collision experiments.

   ↳ nucl-thhep-phnucl-ex0 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.