Search

It has recently been suggested that differences in the charge radii of mirror nuclei ($\Delta R^{\rm mirr}_{\rm ch}$) are strongly correlated with the neutron-skin thickness ($R_{\rm skin}$) of neutron-rich nuclei and with the slope of the symmetry energy ($L$). To test this assumption, we present ab initio calculations of $R_{\rm skin}$ in $^{48}$Ca and $^{208}$Pb, $\Delta R^{\rm mirr}_{\rm ch}$ in $^{36}$Ca$-^{36}$S, $^{38}$Ca$-^{38}$Ar, $^{41}$Sc$-^{41}$Ca, $^{48}$Ni$-^{48}$Ca, $^{52}$Ni$-^{52}$Cr, and $^{54}$Ni$-^{54}$Fe mirror pairs, and $L$. Employing the recently developed 34 chiral interaction samples, identified by the history matching approach, we conduct rigorous statistical analysis of correlations among $\Delta R^{\rm mirr}_{\rm ch}$, $R_{\rm skin}$ and $L$, accounting for quantified uncertainties from low-energy constants of chiral interaction, chiral effective field theory truncation and many-body method approximation. The ab initio results reveal an appreciable $\Delta R^{\rm mirr}_{\rm ch}-L$ correlation in $fp$-shell mirror pairs. However, contrary to previous studies, the present calculation finds that the studied $sd$-shell mirror pairs do not exhibit any $\Delta R^{\rm mirr}_{\rm ch}-L$ correlation.

The broad physics reach of the LUX-ZEPLIN (LZ) experiment covers rare phenomena beyond the direct detection of dark matter. We report precise measurements of the extremely rare decay of $^{124}$Xe through the process of two-neutrino double electron capture (2$\nu$2EC), utilizing a $1.39\,\mathrm{kg} \times \mathrm{yr}$ isotopic exposure from the first LZ science run. A half-life of $T_{1/2}^{2\nu2\mathrm{EC}} = (1.09 \pm 0.14_{\text{stat}} \pm 0.05_{\text{sys}}) \times 10^{22}\,\mathrm{yr}$ is observed with a statistical significance of $8.3\,\sigma$, in agreement with literature. First empirical measurements of the KK capture fraction relative to other K-shell modes were conducted, and demonstrate consistency with respect to recent signal models at the $1.4\,\sigma$ level., Comment: 15 pages, 3 figures

Molecular dynamics approaches use wave packets as nucleon wave functions to simulate the time evolution of nuclear reactions. It is crucial to activate the momentum fluctuation inherent in each wave packet so that it properly affects the time evolution. In the antisymmetrized molecular dynamics (AMD) model, this has traditionally been done by splitting the wave packets, i.e., by introducing a random fluctuation to the wave packet center of each particle. The present work proposes an improved approach to activate the fluctuation in both the one-body mean-field propagation and the two-nucleon collision processes, consistently based on the gradual or sudden change of the degree of isolation, which is derived from the fragment number function used for the zero-point energy subtraction. This new method is applied to the 12C + 12C and 12C + p reactions at about 100 MeV/nucleon, focusing on the momentum distribution of the 11B fragments produced by one-proton removal from the 12C projectile. The results show that, with the momentum fluctuation suitably activated, the method correctly accounts for the recoil from the removed nucleon to the residue and the 11B momentum distribution is significantly improved, while without activating the fluctuation the distribution is too narrow compared to the experimental data. Furthermore, the AMD results indicate that the momentum distribution consists of two components; one is the high $P_z$ component with a small shift from the beam velocity, resulting from the simple removal of a proton after an energetic collision with a target particle; the other is the low $P_z$ component with a larger peak shift resulting from the decay of an excited 12C nucleus in a longer time scale. The activation of momentum fluctuation mainly affects the high $P_z$ component to broaden it. The role of cluster correlations in this problem is also investigated., Comment: 15 pages, 13 figures

We have measured the flavor dependence of multiplicities for pi^+ and pi^- production in semi-inclusive deep-inelastic scattering (SIDIS) on proton and deuteron targets to explore a possible charge symmetry violation in fragmentation functions. The experiment used an electron beam with energies of 10.2 and 10.6 GeV at Jefferson Lab and the Hall-C spectrometers. The electron kinematics spanned the range 0.3

We present calculations of dielectron anisotropic flow in heavy-ion collisions at HADES beam energies from a hadronic transport approach. The ongoing experimental analysis employs the traditional reaction plane method to evaluate the flow coefficients $v_n$ and claims to see isotropic radiation from the thermal quark-gluon plasma. We show in this work, that in the region above the pion mass, the dilepton flow measurement might suffer from cancellation effects that mask the complicated underlying dynamics. Contributions from different baryonic and mesonic resonances show collective behaviour with different signs and lead to an overall vanishing elliptic flow. To differentiate the different contributions, we propose to employ the scalar product method, which exploits the previously measured hadronic flow to create different reference planes. As a proof of concept, we calculate the $v_2$ of dielectrons for Ag+Ag collisions at $\sqrt{s_{NN}}=2.55$ $\mathrm{GeV}$ with both methods and investigate the contribution of each source, concluding that the scalar product method provides the proton and pion tagged flow coefficients as two distinct measurements, disentangling the various dilepton sources., Comment: 10 pages, 7 figures

Recent results from ALICE and CMS show a low-transverse-momentum enhancement of charm baryon-to-meson production ratios over model predictions based on e$^+$e$^-$ collisions. Several mechanisms are proposed to understand this phenomenon. New measurements by the LHCb and ALICE experiments show a similar enhancement in the beauty sector. We explore this enhancement in terms of event activity using the color-reconnection beyond leading order approximation model. We propose sensitive probes relying on the event shape that will allow for the differentiation between the proposed beauty-production scenarios using freshly collected LHC Run-3 data, and we also compare these to predictions for charm. Our results will contribute to a deeper theoretical understanding of the heavy-flavor baryon enhancement and its relation to baryon enhancement in general., Comment: Submiited to IJMPA Special Issue Zim\'anyi School 2023

This review paper describes the energy-upgraded CEBAF accelerator. This superconducting linac has achieved 12 GeV beam energy by adding 11 new high-performance cryomodules containing eighty-eight superconducting cavities that have operated CW at an average accelerating gradient of 20 MV/m. After reviewing the attributes and performance of the previous 6 GeV CEBAF accelerator, we discuss the upgraded CEBAF accelerator system in detail with particular attention paid to the new beam acceleration systems. In addition to doubling the acceleration in each linac, the upgrade included improving the beam recirculation magnets, adding more helium cooling capacity to allow the newly installed modules to run cold, adding a new experimental hall, and improving numerous other accelerator components. We review several of the techniques deployed to operate and analyze the accelerator performance, and document system operating experience and performance. In the final portion of the document, we present much of the current planning regarding projects to improve accelerator performance and enhance operating margins, and our plans for ensuring CEBAF operates reliably into the future. For the benefit of potential users of CEBAF, the performance and quality measures for beam delivered to each of the experimental halls is summarized in the appendix., Comment: 66 pages, 73 figures, 21 tables

The present work deals with the e+ e- pair production in the d(p,e+e-)3He and d(n,e+ e-)3H processes, in order to evidentiate possible effects due to the exchange of a hypothetical low-mass boson, the so-called X17. These processes are studied for energies of the incident beams in the range 18-30 MeV, in order to have a sufficient energy to produce such a boson, whose mass is estimated to be around 17 MeV. We first analyze them as a purely electromagnetic processes, in the context of a state-of-the-art approach to nuclear strong-interaction dynamics and nuclear electromagnetic currents, derived from chiral effective field theory chiEFT. Next, we examine how the exchange of a hypothetical low-mass boson would impact the cross sections for such processes. We consider several possibilities, that this boson is either a scalar, pseudoscalar, vector, or axial particle. The main aim of the study is to exploit the specular structure of the 3He and 3H nuclei to investigate the isospin dependency of the X17-nucleon interaction, as the alleged "proto-phobicity"., Comment: 17 pages, 15 figures. arXiv admin note: text overlap with arXiv:2104.07808

The Solenoidal Large Intensity Device (SoLID) is a large acceptance spectrometer capable of operating at the luminosity frontier. It is proposed to fully exploit the scientific potential of the continuous electron beam accelerator facility (CEBAF) 12 GeV energy upgrade at Jefferson Lab. Its conceptual design is mature, having passed multiple reviews and been validated by a successful pre-R\&D phase. The envisioned scientific program consists of three avenues of research, namely the 3D momentum imaging of the structure of the nucleon, the origin of the proton mass through the gluonic gravitational form factors (GFFs), and the search of physics beyond the standard model of particle physics. These avenues are complemented by a growing supplemental list of run group experiments that address a variety of important topics., Comment: (5 pages, 2 figures, DIS2024 conference, Solenoidal Large Intensity Device (SoLID) )

Baryon quantum number is believed to be conserved since baryogenesis in the early Universe. While fractionally charged valence quarks are understood conventionally to each carry a baryon number of 1/3, the baryon junction, a non-perturbative Y-shaped topology of neutral gluons, has also been proposed as an alternative entity tracing the baryon number. Neither scenario has been verified experimentally. The STAR Collaboration reports measurements at mid-rapidity of baryon number ($\boldsymbol{B}$) over the electric charge number difference ($\boldsymbol{\Delta Q}$) in isobar nuclear collisions, and the net-proton yield along rapidity in photonuclear collisions. A larger $\boldsymbol{B/\Delta Q}$ ratio and less asymmetric net-proton yield are observed than predicted from models assigning baryon number to valence quarks. These findings, corroborated by previous measurements in Au+Au collisions, disfavor the valence quark picture.

Production and in-medium modification of hidden strange $\phi$ mesons are studied in proton-nucleus reactions - p+C, p+Cu and p+Pb - at 12 GeV/c, partially measured by the KEK E325 collaboration via the dilepton decay mode. This work is based on the off-shell microscopic Parton-Hadron-String Dynamics (PHSD) transport approach, which provides the dynamical description of strongly interacting hadronic and partonic degrees of freedom in dense matter, and especially makes it possible to simulate in-medium off-shell dynamics of the $\phi$ meson in the reactions studied. Different in-medium scenarios for the modification of the $\phi$ meson spectral function in nuclear matter are investigated: i) dropping pole mass, ii) collisional broadening and iii) simultaneous dropping pole mass and collisional broadening. Even though the $\phi$ meson production in p+A reactions occurs only at densities around or below normal nuclear matter density $\rho_0$, we find visible modifications of the generated dilepton spectra for the in-medium scenarios compared to the vacuum distribution., Comment: 11 pages, 7 figures

The longitudinal structure of the quark-gluon plasma (QGP) consists of several components spanning various scales. However, its short-range features are often obscured by final-state non-flow correlations. Here, we introduce a data-driven approach to separate initial state structures from non-flow effects. The longitudinal structure is found having two distinct components: one that reflects the global twisted geometry of the QGP, and another that captures localized fluctuations in rapidity. The characteristics of this second component, contributing to short- and medium-range flow decorrelations, can be quantified by comparing collisions of nuclei with different shapes. This study represents the first successful attempt to disentangle long- and short-range flow decorrelations from non-flow backgrounds, providing new insights into the initial conditions of heavy-ion collisions., Comment: 6 pages, 4 figures

The ionization potential (IP) of radium monofluoride (RaF) was measured to be 4.969(2)[10] eV, revealing a relativistic enhancement in the series of alkaline earth monofluorides. The results are in agreement with a relativistic coupled-cluster prediction of 4.969[7] eV, incorporating up to quantum electrodynamics corrections. Using the same computational methodology, an improved calculation for the dissociation energy ($D_{e}$) of 5.56[5] eV is presented. This confirms that radium monofluoride joins the small group of diatomic molecules for which $D_{e}>\mathrm{IP}$, paving the way for precision control and interrogation of its Rydberg states.

The masses of the ground and isomeric states in $^{124,125}$Ag have been measured using the phase-imaging ion-cyclotron-resonance technique at the JYFLTRAP double Penning trap mass spectrometer. The ground states of $^{124}$Ag and $^{125}$Ag were found to be 30(250) keV and 250(430) keV less bound but 36 and 110 times more precise than in the Atomic Mass Evaluation 2020, respectively. The excitation energy of $^{124}$Ag$^{m}$, ${E_x = 188.2(25)}$ keV, was determined for the first time. The new precise mass values have been utilised to study the evolution of nuclear structure via two-neutron separation energies. The impact on the astrophysical rapid neutron capture process has been investigated via neutron-capture reaction rate calculations. The precision measurements indicate a more linear trend in two-neutron separation energies and reduce the mass-related uncertainties for the neutron-capture rate of $^{124}$Ag$(n,\gamma)^{125}$Ag by a factor of around 100. The new mass values also improve the mass of $^{123}$Pd, previously measured using $^{124}$Ag as a reference., Comment: 9 pages, 4 figures

We study the forward-backward azimuthal angular correlations of hadrons in association with multi-particle production in the central rapidity region in proton-proton collisions at the LHC. We apply the nucleon energy-energy correlator framework, where the spinning gluon distribution introduces a nontrivial $\cos(2\phi)$ asymmetries. We will demonstrate that the fundamental helicity structure of QCD amplitudes predicts a unique power counting rule: $\cos(2\phi)$ asymmetry starts at ${O}(\alpha_s^2)$ order for dijet, ${O}(\alpha_s)$ for three jet and ${O}(1)$ for four (and more) jet productions. Our results will help us to understand the long standing puzzle of nearside ridge behavior observed in high multiplicity events of $pp$ collisions at the LHC., Comment: 10 pages, 5 figures

The MUon Scattering Experiment (MUSE) was motivated by the proton radius puzzle arising from the discrepancy between muonic hydrogen spectroscopy and electron-proton measurements. The MUSE physics goals also include testing lepton universality, precisely measuring two-photon exchange contribution, and testing radiative corrections. MUSE addresses these physics goals through simultaneous measurement of high precision cross sections for electron-proton and muon-proton scattering using a mixed-species beam. The experiment will run at both positive and negative beam polarities. Measuring precise cross sections requires understanding both the incident beam energy and the radiative corrections. For this purpose, a lead-glass calorimeter was installed at the end of the beam line in the MUSE detector system. In this article we discuss the detector specifications, calibration and performance. We demonstrate that the detector performance is well reproduced by simulation, and meets experimental requirements.

The predicted neutrinoless double-$\beta$ ($0\nu\beta\beta$) decay is the crucial phenomenon to prove the existence of the Majorana neutrino, which gives a foundation to leptogenesis to explain the matter prevalence of the universe. The nuclear matrix element (NME) of $0\nu\beta\beta$ decay is an important theoretical quantity to determine the effective neutrino mass and help the detector design for the next generation of the $0\nu\beta\beta$ decay search. Reliable calculation of this NME is a long-standing problem because of the diversity of the predicted values of the NME. The main reason for this difficulty is that the effective strength of the Gamow-Teller transition operator $g_A$ for this decay is unknown. I will show the lowest-order vertex corrections for the $0\nu\beta\beta$ and the $2\nu\beta\beta$ NME of $^{136}$Xe in the framework of the hybrid application of the quantum field theory to the leptons and the Rayleigh-Schr\"{o}dinger perturbation to the nucleus. The unperturbed nuclear states are obtained by the quasiparticle random-phase approximation. These corrections reduce the $0\nu\beta\beta$ NME by 30%. The effective $g_A$ referring to this reduced NME is also obtained, and it is shown for the first time that the effective $g_A$ for the $0\nu\beta\beta$ NME is not quite different from that for the $2\nu\beta\beta$ NME; the difference is only 10%. This indicates the possibility that the phenomenological effective $g_A$ to reproduce the experimental half-life of the $2\nu\beta\beta$ decay can be approximately used for the calculation of the $0\nu\beta\beta$ NME., Comment: 6 pages, 2 figures, Submitted to proceedings of 42nd Int. Conf. on Higy Energy Physics, 18-24 July 2024, Prague; A sentence on the 2vbb NME was corrected

We study diffractive vector meson production at small-$x$ in the collision of electrons and polarized deuterons $e+d^{\uparrow}$. We consider the polarization dependence of the nuclear wave function of the deuteron, which results in an azimuthal angular dependence of the produced vector meson when the deuteron is transversely polarized. The Fourier coefficients extracted from the azimuthal angular dependence of the vector meson differential cross-section exhibit notable differences between longitudinally and transversely polarized deuterons. The angular dependence of the extracted effective deuteron radius provides direct insight into the structure of the polarized deuteron wave function. Furthermore, we observe slightly increased gluon saturation effects when the deuteron is longitudinally polarized compared to the transversely polarized case. The small-$x$ observables studied in this work will be accessible at the future Electron-Ion Collider.

We present a statistical analysis of nuclear low-lying states within the framework of multireference covariant density functional theory (MR-CDFT) using a relativistic point-coupling energy density functional (EDF). This study is made possible by the newly developed subspace-projected (SP)-CDFT, where the wave functions of nuclear low-lying states for target EDF parameter sets are expanded in a subspace spanned by the wave functions of low-lying states from training parameter sets. We analyze the global sensitivity of excitation energies, electric quadrupole transition strengths, and the nuclear matrix element of neutrinoless double-beta decay in $^{136}$Xe and $^{150}$Nd to EDF parameters, and explore the correlations between these quantities and nuclear matter properties. Furthermore, we quantify the statistical uncertainty of low-lying states through their posterior distributions., Comment: 15 pages with 14 figures and 3 tables

A comparative vacuum ultraviolet spectroscopy study conducted at ISOLDE-CERN of the radiative decay of the $^{229m}$Th nuclear clock isomer embedded in different host materials is reported. The ratio of the number of radiative decay photons and the number of $^{229m}$Th embedded are determined for single crystalline CaF$_2$, MgF$_2$, LiSrAlF$_6$, AlN, and amorphous SiO$_2$. For the latter two materials, no radiative decay signal was observed and an upper limit of the ratio is reported. The radiative decay wavelength was determined in LiSrAlF$_6$ and CaF$_2$, reducing its uncertainty by a factor of 2.5 relative to our previous measurement. This value is in agreement with the recently reported improved values from laser excitation.

We investigate the isovector component in the phenomenological mean field model of nuclei. Lane's isospin dependence, initially proposed for the nuclear optical potential, is reexamined within the context of bound states using the Woods-Saxon potential. We demonstrate that the original parametrization can be reexpressed in terms of parameters associated with the compound nucleus, enhancing its suitability for bound states. Comparisons with the conventional symmetry term are performed to assess how well each approach fits experimental data on single-particle/hole energies and reproduces charge-radius systematics. Our results indicate that Lane's formula provides better accuracy compared with the traditional approach to the nuclear potential. Additionally, we find that the isovector component of the nuclear potential favors a surface-peaked form factor, especially one described by the first derivative of the Fermi like function divided by the radial coordinate. This consideration is crucial for open-shell nuclei where Woods-Saxon eigenfunctions serve as a realistic basis for other many-body methods. Our findings also enable discrimination among various shell-model calculations of the isospin-symmetry breaking correction to superallowed $0^+\rightarrow0^+$ nuclear $\beta$ decays [I.~S. Towner and J.~C. Hardy, Phys. Rev. C {\bf 77}, 025501 (2008)]. This disparity currently constitutes the main source of theoretical uncertainty in subsequent tests of the standard model., Comment: 13 pages, 4 figures

The PHENIX Collaboration has actively pursued a Data and Analysis Preservation program since 2019, the first such dedicated effort at RHIC. A particularly challenging aspect of this endeavor is preservation of complex physics analyses, selected for their scientific importance and the value of the specific techniques developed as a part of the research. For this, we have chosen one of the most impactful PHENIX results, the joint study of direct photons and neutral pions in high-energy d+Au collisions. To ensure reproducibility of this analysis going forward, we partitioned it into self-contained tasks and used a combination of containerization techniques, code management, and robust documentation. We then leveraged REANA (the platform for reproducible analysis developed at CERN) to run the required software. We present our experience based on this example, and outline our future plans for analysis preservation., Comment: Paper submitted to the Proceedings of the Advanced Computing and Analysis Techniques 2024 (ACAT) conference

The jet cross-section and jet-substructure observables in $p$$+$$p$ collisions at $\sqrt{s}=200$ GeV were measured by the PHENIX Collaboration at the Relativistic Heavy Ion Collider (RHIC). Jets are reconstructed from charged-particle tracks and electromagnetic-calorimeter clusters using the anti-$k_{t}$ algorithm with a jet radius $R=0.3$ for jets with transverse momentum within $8.0

The spin polarization of $\Lambda$ hyperons produced in inclusive reactions with unpolarized protons on unpolarized targets has been studied for almost 40 years. The NA61\SHINE experiment at the CERN SPS has a great potential to study transverse polarization in p-p and p-A collisions. In this work, we discuss the impact of magnetic field and limited detector acceptance on the possible polarization measurement by this experiment. Our analysis shows that the magnetic field impact on the $\Lambda$ polarization due to precession is one order of magnitude smaller than the detector acceptance-based polarization bias, and the identification of an experimental signal similar to that observed before by other experiments is possible., Comment: 10 pages, 8 figures

This Letter presents a search for highly ionizing magnetic monopoles in 262$~\mu$b$^{-1}$ of ultraperipheral Pb+Pb collision data at $\sqrt{s_{_\textrm{NN}}}=5.36$ TeV collected by the ATLAS detector at the LHC. A new methodology that exploits the properties of clusters of hits reconstructed in the innermost silicon detector layers is introduced to study highly ionizing particles in heavy-ion data. No significant excess above the background, which is estimated using a data-driven technique, is observed. Using a nonperturbative semiclassical model, upper limits at 95% confidence level are set on the cross-section for pair production of monopoles with a single Dirac magnetic charge in the mass range of 20-150 GeV. The search significantly improves on the previous cross-section limits for production of low-mass monopoles in ultraperipheral Pb+Pb collisions., Comment: 33 pages in total, author list starting page 16, 3 figures, submitted to in Phys. Rev. Lett. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2023-01/

The sensitivity of underground experiments searching for rare events such as dark matter, neutrino interactions or several beyond the standard model phenomena is often limited by the background caused by neutrons from spontaneous fission and ($\alpha,n$) reactions. A number of codes exist to calculate neutron yields and energy spectra due to these processes. In this paper we present new calculations of neutron production using the modified SOURCES4A code with recently updated cross-sections for ($\alpha,n$) reactions and the comparison of the results with available experimental data. The cross-sections for ($\alpha,n$) reactions in SOURCES4 have been taken from reliable experimental data where possible, complemented by the calculations with EMPIRE 2.19/3.2.3, TALYS 1.96 or evaluated data library JENDL-5 where the data were scarce or unavailable.

We study low-energy nuclear physics at the future Electron-Ion Collider (EIC) at Brookhaven. By comparing the standard theory of electron-nucleus scattering with the equivalent photon method applied to Ultraperipheral Collisions (UPC) at the Large Hadron Collider (LHC) at CERN, we extract valuable insights into both processes. In the limit of extremely high beam energies and small energy transfers, very transparent equations emerge. We apply these equations to analyze nuclear fragmentation in UPCs at the LHC and eA scattering at the EIC, demonstrating that the EIC could facilitate unique photonuclear physics studies., Comment: typo corrected, figure 2 replaced with correct one

The uranium-233 neutron capture cross section between 3 keV and 1 MeV was evaluated with the new alpha value recently measured at the Los Alamos National Laboratory LANCE facility and compiled in the EXFOR library. The obtained capture cross section is systematically lower than those in the latest versions of the major general purpose nuclear data libraries, and the reduction from the JENDL-5 library is close to 50% around 20 keV. The newly evaluated cross section was benchmarked against 166 criticality experiments chosen from the ICSBEP handbook by performing Monte Carlo neutron transport calculation with the JENDL-5 library, and slight reduction of the cumulative chi-square value was achieved by adoption of the newly evaluated capture cross section., Comment: Submitted to Annals of Nuclear Energy

Transfer learning (TL) allows a deep neural network (DNN) trained on one type of data to be adapted for new problems with limited information. We propose to use the TL technique in physics. The DNN learns the physics of one process, and after fine-tuning, it makes predictions for related processes. We consider the DNNs, trained on inclusive electron-carbon scattering data, and show that after fine-tuning, they accurately predict cross sections for electron interactions with nuclear targets ranging from lithium to iron. The method works even when the DNN is fine-tuned on a small dataset., Comment: 4 pages, 2 figures

The analysis of Pb+Pb data for net-charge fluctuations at LHC energies within the HYDJET++ model is presented. The strongly intensive quantities $D$ and $\Sigma$ are used to get rid of the effects related to volume fluctuations of the system. We employ two versions of the HYDJET++ for the analysis. The first one is the standard or default version, whereas the second one represents its further modification, which takes into account explicit event-by-event conservation of the electric net-charge of produced particles. Inclusion of the canonical net-charge conservation in the model allows one for better description of the experimental data obtained by the ALICE and the CMS Collaborations. Comparison with calculations of other models is also presented., Comment: LATEX, 8 pages, 8 figures

The EIC will deliver collisions of electrons with protons and nuclei at a wide variety of energies and at luminosities up to 1000 times higher than HERA. Precise measurement of both the scattered electron and the hadronic final state is crucial for the physics of the EIC, necessitating unique designs for the electromagnetic and hadronic calorimeters in the backward, central, and forward regions. To ensure maximal containment of energy and acceptance for the required physics processes, the ePIC detector employs calorimetry over almost the entire polar angle. These proceedings provide an overview of the current calorimeter designs being employed in ePIC.

The angular distributions of elastic scattering of $^{7}$Li, as well as the lithium-induced reaction of one-nucleon transfers $^{10}$B($^{7}$Li,$^{6}$Li)$^{11}$B were measured at $E_{lab}$ = 58 MeV. Experiment was done using U-400 accelerator beam of the FLNR JINR, Dubna. Angular distribution for reaction $^{10}$B($^{7}$Li,$^{6}$Li)$^{11}$B with excitation of the 3.56 MeV state ($^{6}$Li*) is present for the first time. The DWBA analysis of the differential cross section of the $^{10}$B($^{7}$Li,$^{6}$Li)$^{11}$B ground state (g.s.) transition and excited ($J^\pi$ = 0$^+$, $T$ = 1, $E$ = 3.56 MeV) state of $^{6}$Li transition was performed. The optical model potentials were obtained by fitting of measured elastic scattering data and evaluating parameters for the output reaction channels. Phenomenological approaching based on solving an approximate equation for the reaction form factor was used to determine its radial dependence and empirical values of asymptotic normalization coefficient (ANC). Obtained values of ANCs for the $^{6}$Li$_\text{g.s.}$ and $^{6}$Li*(3.56 MeV) states are similar to literature one. Comparison of the radial dependences of form factors shows that the wave function of the $^{6}$Li nucleus in excited ($J^\pi$ = 0$^+$, $T$ = 1, $E$ = 3.56 MeV) state has increased spatial dimension compared to the ground state, and in both cases some larger spatial size than the ground states of the $^{11}$B and $^{10}$B. Within the framework of our analysis, we can confirm that the radius of the $^{6}$Li nucleus in the 3.56 MeV state is larger than in the ground state. This result is an argument in favor of a halo existence in $^{6}$Li*(3.56 MeV) state, while the question of a halo in $^{6}$Li$_\text{g.s.}$ still leaves open., Comment: 9 figures, 4 tables

Based on available models and experimental data, the sputtering of target atoms in long-term experiments with intense heavy ion (HI) beams has been considered. The experiments on the synthesis of superheavy nuclei (SHN), which are carried out in laboratories around the world, are examples of such experiments encountering the target atoms sputtering in specific conditions. Rotating wheels with a relatively large target annulus area are used in these experiments to reduce the temperature and radiation loads on the target. Large areas of rotating targets allow one to reduce the sputtering yields of target atoms significantly. The question arises about the reliability of these yields in experiments on the synthesis of SHN with Z > 118. These nuclei can be produced with extremely low cross sections, requiring HI beam doses exceeding 1020 particles passed through the target to observe several decay events of the thus synthesized SHN. Estimates based on approximations and simulations considered in this work are presented and compared with some data on actinide target sputtering obtained in experiments performed on the synthesis of SHN., Comment: 19 pages, 12 figures

This paper presents a measurement of jet-track correlations in photon-jet events, using 1.72 nb$^{-1}$ of Pb+Pb data at $\sqrt{s_{\text{NN}}}$ = 5.02 TeV recorded with the ATLAS detector at the LHC. Events with energetic photon-jet pairs are selected, where the photon and jet are approximately back-to-back in azimuth. The angular correlation between jets and charged-particle tracks with transverse momentum ($p_\text{T}$) in the range 0.5-2.0 GeV in the hemisphere opposite to the jet, $|\Delta\phi\text{(jet,track)}|>\pi/2$, is measured as a function of their relative pseudorapidity difference, $|\Delta\eta\text{(jet,track)}|$. In central Pb+Pb collisions, these correlations are predicted to be sensitive to the diffusion wake in the quark-gluon plasma resulting from the lost energy of high-$p_\text{T}$ partons traversing the plasma, with a characteristic modification as a function of $|\Delta\eta\text{(jet,track)}|$. The correlations are examined with different selections on the jet-to-photon $p_\text{T}$ ratio to select events with different degrees of energy loss. No diffusion wake signal is observed within the current sensitivity and upper limits at 95% confidence level on the diffusion wake amplitude are reported., Comment: 36 pages in total, author list starting page 19, 8 figures, 0 tables, submitted to Phys. Rev. C. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2024-01/

Multimessenger studies of heavy-ion collisions, using hadrons and electromagnetic probes, can reveal the properties of the created QCD matter from different perspectives. This study calculates the thermal dilepton invariant mass spectra and thermal photon transverse momentum spectra in Au+Au collisions at low beam energies from the Beam Energy Scan program, using a (3+1)-dimensional multistage hydrodynamic model calibrated by rapidity-dependent hadronic distributions. The effects of thermodynamic rapidity variation, baryon chemical potential, and fluid expansion on the spectra are explored. Methods for extracting temperature from photon and dilepton spectra are examined by comparison with the underlying hydrodynamic temperature. The possibility of combining photon and dilepton spectra to extract radial flow is also investigated. This study provides insights into measuring the thermodynamic properties of the created systems in heavy-ion collisions using multiple messengers through two fundamental interactions within the same framework., Comment: 9 pages, 8 figures

The region of $N\approx Z\approx 40$ has long been associated with strongly deformed nuclear configurations. The presence of this strong deformation was recently confirmed through lifetime measurements in $N\approx Z$ Sr and Zr nuclei. Theoretically, however, these nuclei present a challenge due to the vast valence space required to incorporate all deformation driving interactions. Recent state-of-the-art predictions indicate a near axial prolate deformation for $N=Z$ and $N=Z+2$ nuclei between $N=Z=36$ and $N=Z=40$. In this work we investigate the shores of this island of deformation through a sub-barrier Coulomb excitation study of the $N=Z+4$ nucleus, \textsuperscript{80}Sr. Extracting a spectroscopic quadrupole moment of $Q_s(2^+_1) = 0.45^{+0.83}_{-0.88}$~eb, we find that \textsuperscript{80}Sr is inconsistent with significant axial prolate deformation. This indicates that the predicted region of strong prolate deformation around $N=Z=40$ is tightly constrained to the quartet of nuclei: \textsuperscript{76,78}Sr and \textsuperscript{78,80}Zr., Comment: Submitted to Physics Letters B

We present the first calculation of next-to-leading order (NLO) factorized QED contributions to the short-distance hard coefficients of inclusive lepton-hadron deep inelastic scattering (DIS) in a joint QCD and QED factorization approach. We demonstrate how the joint factorization consistently factorize all perturbative collinear sensitivities of partonic scattering in both QCD and QED into corresponding universal hadron and lepton distribution functions without the need of any parameters other than the standard factorization scale. We discuss the necessary modification to DGLAP-type evolution of the parton and lepton distribution functions in this joint factorization approach. We also discuss the potential impact of this joint factorization approach on the extraction of partonic information from lepton-hadron DIS., Comment: 6 pages, 2 figures; contributed talk to DIS2024

The JETSCAPE Collaboration reports a new determination of the jet transport parameter $\hat{q}$ in the Quark-Gluon Plasma (QGP) using Bayesian Inference, incorporating all available inclusive hadron and jet yield suppression data measured in heavy-ion collisions at RHIC and the LHC. This multi-observable analysis extends the previously published JETSCAPE Bayesian Inference determination of $\hat{q}$, which was based solely on a selection of inclusive hadron suppression data. JETSCAPE is a modular framework incorporating detailed dynamical models of QGP formation and evolution, and jet propagation and interaction in the QGP. Virtuality-dependent partonic energy loss in the QGP is modeled as a thermalized weakly-coupled plasma, with parameters determined from Bayesian calibration using soft-sector observables. This Bayesian calibration of $\hat{q}$ utilizes Active Learning, a machine--learning approach, for efficient exploitation of computing resources. The experimental data included in this analysis span a broad range in collision energy and centrality, and in transverse momentum. In order to explore the systematic dependence of the extracted parameter posterior distributions, several different calibrations are reported, based on combined jet and hadron data; on jet or hadron data separately; and on restricted kinematic or centrality ranges of the jet and hadron data. Tension is observed in comparison of these variations, providing new insights into the physics of jet transport in the QGP and its theoretical formulation., Comment: 20 pages, 10 figures, 2 tables, submitted to PRC; updated acknowledgements

We present coupled-cluster computations of nuclei with neutron number $N=50$ "south" of $^{78}$Ni using nucleon-nucleon and three-nucleon forces from chiral effective field theory. We find an erosion of the magic number $N=50$ toward $^{70}$Ca manifesting itself by an onset of deformation and increased complexity in the ground states. For $^{78}$Ni, we predict a low-lying rotational band consistent with recent data, which up until now has been a challenge for ab initio nuclear models. Ground states are deformed in $^{76}$Fe, $^{74}$Cr, and $^{72}$Ti, although the spherical states are too close in energy to unambiguously identify the shape of the ground state within the uncertainty estimates. In $^{70}$Ca, the potential energy landscape from quadrupole-constrained Hartree-Fock computations flattens, and the deformation becomes less rigid. We also compute the low-lying spectra and $B({\rm E2})$ values for these neutron-rich $N=50$ nuclei., Comment: 10 pages, 6 figures, supplementary material

At energies of a few GeV per nucleon, nuclear collisions exhibit phenomena more complex than the individualistic nucleon interactions observed at much higher energies. From recent results on proton number fluctuations in Au + Au collisions at $\sqrt{s_{NN}}=2.4$~GeV obtained by the HADES experiment at GSI, we suggest that measuring the multiplicity distributions heavy-ion collisions can be used to probe density fluctuations associated with correlation phenomena. By using the combinant analysis, one can obtain new information contained in them and otherwise unavailable, which may broaden our knowledge of the particle interactions mechanism.

The discovery of a new, strong reaction channel of the deuteron-deuteron fusion at very low energies might have major consequences for the construction of a future clean and efficient energy source. Following the first theoretical and experimental indications for the existence of the deuteron-deuteron threshold resonance in the $^4$He nucleus and its dominant decay by the internal $e^+e^-$ pair creation, we present here an extensive experimental study confirming emission of high-energy electrons and positrons. A simultaneous use of Si charged particle detectors of different thicknesses and large volume NaI(Tl) and HPGe detectors has allowed for the first time to determine the branching ratio between emitted protons, neutrons and $e^+e^-$ pairs for deuteron energies down to 5 keV. The high-energy positrons could be unambiguously detected by their bremsstrahlung spectra and annihilation radiation, supported by the Monte Carlo Geant4 simulations. The theoretical calculations, based on a destructive interference between the threshold resonance and the known broad resonance in $^4$He, agree very well with experimentally observed increase of branching ratios for lowering projectile energies. The partial width of the threshold resonance for the $e^+e^-$ pair creation should be at least 10 times larger than that of the proton channel.

The E895 and STAR experiments demonstrate that the slopes of directed flow with respect to rapidity ($dv_1/dy|_{y=0}$) of mesons are negative in the low transverse momentum ($p_T$) region, $p_T < 0.8$ GeV/$c$, in Au + Au collisions at $\sqrt{s_{NN}} = 3.0 - 3.9$ GeV. Using the transport model JAM, we investigate the directed flow of $\pi^{\pm}$, $K^{\pm}$, and $K^0$ as functions of rapidity, $p_T$, and collision energy in Au + Au collisions at the same energies as those in the E895 and STAR experiments. We find that the JAM model can qualitatively reproduce the anti-flow of $K^0_S$ observed in the E895 experiment. The $v_1$ slopes of pions and kaons are analyzed as functions of the $p_T$ window, revealing a strong $p_T$ dependence of the $v_1$ slopes. Negative $v_1$ slopes are observed in the low $p_T$ region, $p_T < 0.8$ GeV/$c$, while positive slopes are shown in the higher $p_T$ region. We find that the shadowing effect from spectators is crucial in generating the anti-flow of mesons at low $p_T$ in the high baryon density region., Comment: 7 pages, 7 figures, accepted by Phys. Rev. C

To synthesize superheavy element 119 is becoming highly concerned as several experimental projects in major laboratories are being pursued. This work studied the survival probabilities of compound superheavy nuclei after multiple neutron emissions based on microscopic energy dependent fission barriers, demonstrating a significant role of triaxial deformation in decreasing the first fission barriers in the heaviest region. Together with the fusion cross sections by the dinuclear system model, the optimal energy and the residual cross section of $^{243}$Am($^{48}$Ca, 3$n$)$^{288}$Mc are reproduced. Finally the cross sections and optimal beam energies of $^{243}$Am+$^{54}$Cr and $^{249}$Bk+$^{50}$Ti reactions are estimated, providing clues for the synthesis of new elements., Comment: 5 pages, 3 figures

Low-lying states of $^{94}$Zr were investigated via low-energy multi-step Coulomb excitation. From the measured $\gamma$-ray yields, 13 reduced transition probabilities between low-spin states were determined, together with the spectroscopic quadrupole moments of the $2_{1,2}^+$ states. Based on this information, for the first time in the Zr isotopic chain, the shapes of the $0_{1,2}^+$ states including their deformation softness were inferred in a model-independent way using the quadrupole sum rules approach. The ground state of $^{94}$Zr possesses a rather diffuse shape associated with a spherical configuration, while the $0_2^+$ state is oblate and more strongly deformed. The observed features of shape coexistence in $^{94}$Zr are in agreement with Monte-Carlo shell-model predictions, and the present results are vital to refine the IBM-CM description of the Zr isotopes around $A\approx 100$ in terms of an intertwined quantum phase transition., Comment: 6 pages, 3 figures

Theoretical considerations are made for the nuclear excitation from the ground state to the 8 eV $^{229m}$Th isomer via near-resonant electron transitions in Sb-like ($q=39+$) thorium ions. The energy of the first excited atomic state ($J=7/2$) in the $^{229}$Th$^{39+}$ ion is estimated to be 8.308$\pm$0.011 eV, which is very close to the new reference value for the $^{229m}$Th nuclear isomer energy, 8.338$\pm$0.024 eV [Kraemer et al., Nature 617, 706 (2023)]. It was found that within the uncertainty range of both atomic and nuclear excitation energies, the rate of nuclear excitation by electron transition can vary by more than 20 orders of magnitude. Our results indicate that the upper theoretical limit for the $^{229m}$Th isomer excitation rate reaches an enormous value of $1.05\times10^{16}$ s$^{-1}$ at resonance ($\Delta=0$ meV). Additionally, it was shown that using an electron beam ion trap (EBIT), the production of the $^{229}$Th isomer can reach rates ranging from tenths to approximately $6\times10^{19}$ s$^{-1}$. Thus, EBIT experimental studies could serve as an extremely sensitive tool for the independent verification of the excitation energy of the isomeric state in the $^{229}$Th nucleus.

The background index is an important quantity which is used in projecting and calculating the half-life sensitivity of neutrinoless double-beta decay ($0\nu\beta\beta$) experiments. A novel analysis framework is presented to calculate the background index using the specific activities, masses and simulated efficiencies of an experiment's components as distributions. This Bayesian framework includes a unified approach to combine specific activities from assay. Monte Carlo uncertainty propagation is used to build a background index distribution from the specific activity, mass and efficiency distributions. This analysis method is applied to the MAJORANA DEMONSTRATOR, which deployed arrays of high-purity Ge detectors enriched in $^{76}$Ge to search for $0\nu\beta\beta$. The framework projects a mean background index of $\left[8.95 \pm 0.36\right] \times 10^{-4}$cts/(keV kg yr) from $^{232}$Th and $^{238}$U in the DEMONSTRATOR's components., Comment: 9 pages, 3 figures

In this work, we present a calculation of the triton $\beta$-decay lifetime using Nuclear Lattice Effective Field Theory (NLEFT) at next-to-next-to-next-to-leading order in the chiral expansion. By incorporating a non-perturbative treatment of the higher-order corrections, we achieve consistent predictions for the Fermi and Gamow-Teller matrix elements, which are crucial for determining the triton lifetime. Our results are consistent with earlier theoretical calculations, confirming the robustness of our approach. This study marks a significant advancement in the systematic application of NLEFT to nuclear $\beta$-decay processes, paving the way for future high-precision calculations in more complex nuclear systems. Additionally, we discuss potential improvements to our approach, including the explicit inclusion of two-pion exchange mechanisms and the refinement of three-nucleon forces. These developments are essential for extending the applicability of NLEFT to a broader range of nuclear phenomena, including neutrinoless double-$\beta$ decay., Comment: 8 pages, 3 figures

We propose a novel method to probe light-quark dipole moments by examining the azimuthal asymmetries between a collinear pair of hadrons in semi-inclusive deep inelastic lepton scattering off an unpolarized proton target at the Electron-Ion Collider. These asymmetries provide a means to observe transversely polarized quarks, which arise exclusively from the interference between the dipole and the Standard Model interactions, thereby depending linearly on the dipole couplings. We demonstrate that this novel approach can enhance current constraints on light-quark dipole operators by an order of magnitude, free from contamination of other new physics effects. Furthermore, it allows for a simultaneous determination of both the real and imaginary parts of the dipole couplings, offering a new avenue for investigating potential $CP$-violating effects at high energies., Comment: 6 pages, 2 figures

The even-odd staggering in fission fragments yield distributions is an important observable to address the role of intrinsic excitations in the fission process. However, its computation as a function of the fragment split is an ill-posed problem that is usually solved through certain assumptions. Arguably, the most widely used method for its computation is the Log-third-difference method, which assumes an underlying local Gaussian distribution. Experimental data of the even-odd effect show sharp features and peaks that are a challenge for the Log-third difference method (or any method for that matter). This paper presents a detailed study of the performance of the Log-third difference method and describes three strategies for improving the precision and accuracy around these sharp features. The best results are obtained with an iterative application of the method and with the use of a multi-Gaussian fit. In regions with a smooth behaviour, the direct application of the Log-third-difference method remains the best option., Comment: 15 pages, 13 figures

Constituent quarks in a nucleon are the essential elements in the standard ``quark model" associated with the electric charge, spin, mass, and baryon number of a nucleon. Quantum Chromodynamics (QCD) describes nucleon as a composite object containing current quarks (valence quarks and sea (anti-)quarks) and gluons. These subatomic elements and their interactions are known to contribute in complex ways to the overall nucleon spin and mass. In the early development of QCD theory in the 1970s, an alternative hypothesis postulated that the baryon number might manifest itself through a non-perturbative configuration of gluon fields forming a Y-shaped topology known as the gluon junction. In this work, we propose to test such hypothesis by measuring (i) the Regge intercept of the net-baryon distributions for $e$+($p$)Au collisions, (ii) baryon and charge transport in the isobaric ratio between $e$+Ru and $e$+Zr collisions, and (iii) target flavor dependence of proton and antiproton yields at large rapidity, transported from the hydrogen and deuterium targets in $e+p$(d) collisions. Our study indicates that these measurements at the EIC can help determine what carries the baryon number., Comment: 6 pages, 7 figures, submitted for publication