Fri·Jan 20, 2023Friday·January 20, 2023

1. 01*

   Comprehensive Study of Radon Progeny Attachment to Surfaces

   D. Chernyak🇺🇸 · J. Howell🇺🇸 · D. Majumdar🇮🇳 · N. Mukherjee🇺🇸 · O. Nusair🇺🇸 · A. Piepke🇺🇸

   Low energy, low rate experiments, such as searches for neutrinoless double beta decay and dark matter, require unprecedentedly low levels of background in order to deliver their full science potential. ${}^{210}$Po driven, neutron induced background, caused by nuclear $(\alpha ,n)$-reactions on low-Z materials, direct background contributions of the ${}^{210}$Po $\alpha$-radiation and desorption of the ${}^{210}$Pb progeny ${}^{210}$Bi from surfaces into the detector medium are of particular of concern. These backgrounds depend on details of the components' exposure to radon-loaded lab air and, thus, their handling history. The attachment rates of airborne radon progeny to surfaces, needed for the estimation of these background rates, are poorly understood. This article reports the results of a campaign comprising of more than 1200 attachment measurements, performed for 9 different materials. Correlations of the attachment with environmental parameters such as air exchange rate, electrical surface potential, temperature, atmospheric pressure, and relative humidity have been studied and found to be significant only in case of the first two. Attachment modelling, using the Jacobi model, is compared to data.

   nucl-exPRC(2023)·5 citations
2. 02*

   Enhancing the performance of solenoidal spectrometers for inverse reactions

   P. A. Butler🇬🇧

   Helical-orbit solenoidal spectrometers, in which the target and detector are placed inside a uniform magnetic field, have been utilised for more than a decade to study nuclear reactions in inverse kinematics, induced by radioactive beams. Methods to improve the final state energy resolution are presented and the inclusion of an active gas target is proposed to improve the performance of the spectrometer.

   nucl-exProc.Roy.Soc.Lond.A(2023)·1 citation
3. 03*

   Improved methodologies to study the performance of the ANET Compact Neutron Collimator

   Oriol Sans-Planell🇮🇹 · Francesco Cantini · Marco Costa🇮🇹 · Elisabetta Durisi🇮🇹 · Francesco Grazzi🇮🇹 · Ettore Mafucci🇮🇹 · Valeria Monti🇮🇹 · Roberto Bedogni🇮🇹 · Yueer Li🇨🇳 · Lambert van Eijck

   The ANET project aims at developing 2D compact neutron collimators for neutron imaging applications. The results of the ANET collimator performances, presented in this communication, are based on data collected at the FISH beamline at TU-Delft. Two independent methods to evaluate the neutron radiography resolution are described and discussed, as well as a comparison of the beam divergence with or without the ANET collimator.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2023)·0 citations
4. 04*

   Flow Distribution Analysis as A Probe of Nuclei Deformity

   Hadi Mehrabpour🇩🇪 · S. M. A. Tabatabaee🇮🇷

   We study the flow harmonic distribution in deformed nuclei. To do this, we use the standard Gram-Charlier method to find the higher-order correction to the well-known Bessel-Gaussian distribution. We find that, apart from the necessity of including a shift parameter ${\bar{v}}_n$, the modified flow distribution describes the flow distribution of quadrupole and octupole deformation accurately. Using the shifted radial distribution, arising from this method, we scrutinize the effect of deformation on flow distribution. Assuming a linear relation between observables of spherical and deformed collisions, ${\mathcal{O}}_D={\mathcal{O}}_S+{\left({\sum }_{m=2}{a}_{k,m}{\beta }_m\right)}^{2k}$, for events with a fixed centrality, we compare the flow distribution of deformed and spherical nuclei. We also propose a way to measure ${\bar{v}}_2$ in asymmetric nuclei collisions.

   ↳ nucl-thnucl-exPRC(2023)·7 citations
5. 05*

   Nucleon Resonance Electroexcitation Amplitudes and Emergent Hadron Mass

   Daniel S. Carman🇺🇸 · Ralf W. Gothe🇺🇸 · Victor I. Mokeev🇺🇸 · Craig D. Roberts🇨🇳

   Understanding the strong interaction dynamics that govern the emergence of hadron mass (EHM) represents a challenging open problem in the Standard Model. In this paper we describe new opportunities for gaining insight into EHM from results on nucleon resonance ($N^{\ast }$) electroexcitation amplitudes (i.e. ${\gamma }_{v}p{N}^{\ast }$ electrocouplings) in the mass range up to 1.8\,GeV for virtual photon four-momentum squared (i.e. photon virtualities $Q^2$) up to 7.5\,GeV${}^2$ available from exclusive meson electroproduction data acquired during the 6-GeV era of experiments at Jefferson Laboratory (JLab). These results, combined with achievements in the use of continuum Schwinger function methods (CSMs), offer new opportunities for charting the momentum dependence of the dressed quark mass from results on the $Q^2$-evolution of the ${\gamma }_{v}p{N}^{\ast }$ electrocouplings. A successful description of the $\Delta (1232)3/2^{+}$ and $N(1440)1/2^{+}$ electrocouplings has been achieved using CSMs with, in both cases, common momentum-dependent mass functions for the dressed quarks, for the gluons, and the same momentum-dependent strong coupling. Parameter-free CSM predictions for the electrocouplings of the $\Delta (1600)3/2^{+}$ became available in 2019. The experimental results obtained in the first half of 2022 have confirmed the CSM predictions. We also discuss prospects for these studies during the 12-GeV era at JLab using the CLAS12 detector, with experiments that are currently in progress, and canvass the physics motivation for continued studies in this area with a possible increase of the JLab electron beam energy up to 22\,GeV.

   ↳ hep-phnucl-exnucl-thParticles(2023)·46 citations
6. 06*

   Bayesian inference of nucleus resonance and neutron skin

   Jun Xu🇨🇳

   In this proceeding, we have presented some highlight results on the constraints of the nuclear matter equation of state (EOS) from the data of nucleus resonance and neutron-skin thickness using the Bayesian approach based on the Skyrme-Hartree-Fock model and its extension. Typically, we have discussed the anti-correlation and positive correlation between the slope parameter and the value of the symmetry energy at the saturation density under the constraint of, respectively, the neutron-skin thickness and the isovector giant dipole resonance. We have shown that the Bayesian analysis can help to find a compromise for the ``PREXII puzzle'' and the ``soft Tin puzzle". We have further illustrated the possible modifications on the constraints of lower-order EOS parameters as well as the relevant correlation when higher-order EOS parameters are incorporated as independent variables. For a given model and parameter space, the Bayesian approach serves as a good analysis tool suitable for multi-messengers versus multi-variables, and is helpful for constraining quantitatively the model parameters as well as their correlations.

   ↳ nucl-thnucl-exAtomic Energ.Sci.Technol.(2023)·1 citation
7. 07*

   Measuring deformed neutron skin with free spectator nucleons in relativistic heavy-ion collisions

   Lu-Meng Liu🇨🇳 · Jun Xu🇨🇳 · Guang-Xiong Peng🇨🇳

   The neutron skin in deformed nuclei is generally not uniformly distributed but has an angular distribution, depending on both the spin-dependent nuclear interaction and the nuclear symmetry energy. To extract the information of the deformed neutron skin, we have explored the possibility of using free spectator nucleons in central tip-tip and body-body collisions at top RHIC energy with four typical deformed nuclei. The density distributions of neutrons and protons are consistently obtained from the Skyrme-Hartree-Fock-Bogolyubov calculation, and the angular distribution of the neutron skin can be varied by adjusting the strength of the nuclear spin-orbit coupling. With the information of spectator nucleons obtained based on a Monte-Carlo Glauber model, the free spectator nucleons are generated from a multifragmentation process. By investigating the results from different systems and with different collision configurations, we found that although it is difficult to probe the deformed neutron skin in ${}^{96}$Zr and ${}^{238}$U by their collisions, it is promising to extract the polar angular distributions of the neutron skin in ${}^{96}$Ru and ${}^{197}$Au by comparing the yield ratios of free spectator neutrons to protons in their central tip-tip and body-body collisions. The proposed observables can be measured by dedicated zero-degree calorimeters in heavy-ion collision experiments that have been carried out in recent years by RHIC.

   ↳ nucl-thhep-exnucl-exPLB(2023)·23 citations
8. 08*

   Revisiting angular momentum conservation in transport simulations of intermediate-energy heavy-ion collisions

   Rong-Jun Liu🇨🇳 · Jun Xu🇨🇳

   Based on the well-calibrated IBUU transport model, we have studied the dynamical effect of incorporating rigorous angular momentum conservation in each collision of particles with homework setups. The constraint of the rigorous angular momentum conservation requires in-plane collisions and side jumps of particles after their collision. Since the option is not unique, we have compared two typical prescriptions with the original one. While the results depend quantitatively on the choice of the prescription, we found that the angular momentum conservation generally reduces local density fluctuations and thus the collision rate, and may have some influence on the density evolution, the collective flow, and even the pion production in transport simulations of intermediate-energy heavy-ion collisions.

   ↳ nucl-thnucl-exUniverse(2023)·3 citations
9. 09*

   Collision geometry effect on free spectator nucleons in relativistic heavy-ion collisions

   Lu-Meng Liu🇨🇳 · Jun Xu🇨🇳 · Guang-Xiong Peng🇨🇳

   Based on the deformed nucleon distributions obtained from the constrained Skyrme-Hartree-Fock-Bogolyubov calculation using different nuclear symmetry energies, we have investigated the effects of the neutron skin and the collision geometry on the yield of free spectator nucleons as well as the yield ratio $N_n/N_p$ of free spectator neutrons to protons in collisions of deformed nuclei at RHIC energies. We found that tip-tip (body-body) collisions with prolate (oblate) nuclei lead to fewest free spectator nucleons, compared to other collision configurations. While the $N_n/N_p$ ratio is sensitive to the average neutron-skin thickness of colliding nuclei and the symmetry energy, it is affected by the polar angular distribution of the neutron skin in different collision configurations. We also found that the collision geometry effect can be as large as 50% the symmetry energy effect in some collision systems. Due to the particular deformed neutron skin in ${}^{238}$U and ${}^{96}$Zr, the symmetry energy effect on the $N_n/N_p$ ratio is enhanced in tip-tip ${}^{238}$U+${}^{238}$U collisions and body-body ${}^{96}$Zr+${}^{96}$Zr collisions compared to other collision orientations in the same collision system. Our study may shed light on probing deformed neutron skin by selecting desired configurations in high-energy collisions with deformed nuclei.

   ↳ nucl-thhep-exnucl-exNucl.Phys.Rev.(2023)·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.