Tue·Feb 15, 2022Tuesday·February 15, 2022

1. 01*

   Angular distribution of $\gamma$ rays from the p-wave resonance of ${}^{118}$Sn

   J. Koga🇯🇵 · S. Takada🇯🇵 · S. Endo · H. Fujioka🇯🇵 · K. Hirota🇯🇵 · K. Ishizaki🇯🇵 · A. Kimura🇯🇵 · M. Kitaguchi🇯🇵 · Y. Niinomi · T. Okudaira🇯🇵 · K. Sakai🇯🇵 · T. Shima🇯🇵 and 5 other authors

   The neutron energy-dependent angular distribution of $\gamma$ rays from ${}^{117}\mathrm{Sn}(n,\gamma )$ reaction was measured with germanium detectors and a pulsed neutron beam. The angular distribution was clearly observed in $\gamma$-ray emissions with an energy of 9327 keV which corresponds to the transition from a neutron resonance of ${}^{117}\mathrm{Sn}+n$ to the ground state of ${}^{118}\mathrm{Sn}$. The angular distribution causes an angular-dependent asymmetric resonance shape. An asymmetry $A_{\mathrm{LH}}$ was defined as $(N_{\mathrm{L}}-N_{\mathrm{H}})/(N_{\mathrm{L}}+N_{\mathrm{H}})$, where $N_{\mathrm{L}}$ and $N_{\mathrm{H}}$ are integrated values for lower- and higher-energy regions of a neutron resonance, respectively. We found that the $A_{\mathrm{LH}}$ has the angular dependence of $(A\cos {\theta }_{\gamma }+B)$, where ${\theta }_{\gamma }$ is the $\gamma$-ray emission angle with respect to the incident neutron momentum, with $A=0.394\pm 0.073$ and $B=0.118\pm 0.029$ in the 1.33 eV p-wave resonance.

   nucl-exPRC(2022)·9 citations
2. 02*

   Multi-channel experimental and theoretical constraints for the ${}^{116}$Cd(${}^{20}$Ne,${}^{20}$F)${}^{116}$In charge exchange reaction at 306 MeV

   S. Burrello🇩🇪 · S. Calabrese🇮🇹 · F. Cappuzzello🇮🇹 · D. Carbone🇮🇹 · M. Cavallaro🇮🇹 · M. Colonna🇮🇹 · J. A. Lay🇪🇸 · H. Lenske🇩🇪 · C. Agodi🇮🇹 · J. L. Ferreira🇧🇷 · S. Firat🇹🇷 · A. Hacisalihoglu🇹🇷 and 34 other authors

   Charge exchange (CE) reactions offer a major opportunity to excite nuclear isovector modes, providing clues about the nuclear interaction in the medium. Moreover, double charge exchange (DCE) reactions are proving to be a tempting tool to access nuclear transition matrix elements (NME) related to double beta-decay processes. Through a multi-channel experimental analysis and a consistent theoretical approach of the ${}^{116}$Cd(${}^{20}$Ne,${}^{20}$F)${}^{116}$In single charge exchange (SCE) reaction at 306 MeV, we aim at disentangling from the experimental cross section the contribution of the competing mechanisms, associated with second or higher order sequential transfer and inelastic processes. We measured excitation energy spectra and absolute cross sections for elastic + inelastic, one-proton transfer and SCE channels, using the MAGNEX large acceptance magnetic spectrometer to detect the ejectiles. For the first two channels, we also extracted the experimental cross section angular distributions. The experimental data are compared with theoretical predictions obtained by performing two-step distorted wave Born approximation and coupled reaction channel calculations. We employ spectroscopic amplitudes for single-particle transitions derived within a large-scale shell model approach and different optical potentials for modeling the initial and the final state interactions. The present study significantly mitigates the possible model dependence existing in the description of these complex reaction mechanisms, thanks to the reproduction of several channels at once. In particular, our work demonstrates that the two-step transfer mechanisms produce a non negligible contribution to the total cross section of the ${}^{116}$Cd(${}^{20}$Ne,${}^{20}$F)${}^{116}$In reaction channel, although a relevant fraction is still missing, being ascribable to the direct SCE mechanism, which is not addressed here.

   ↳ nucl-thnucl-exPRC(2022)·35 citations
3. 03*

   Scaling properties of exclusive vector meson production cross section from gluon saturation

   Gregory Matousek🇺🇸 · Vladimir Khachatryan🇺🇸 · Jinlong Zhang🇨🇳

   It is already known from phenomenological studies that in exclusive deep-inelastic scattering off nuclei there appears to be a scaling behavior of vector meson production cross section in both nuclear mass number, $A$, and photon virtuality, $Q^2$, which is strongly modified due to gluon saturation effects. In this work we continue those studies in a realistic setup based upon using the Monte Carlo event generator Sar{\em t}re. We make quantitative predictions for the kinematics of the Electron-Ion Collider, focusing on this $A$ and $Q^2$ scaling picture, along with establishing a small region of squared momentum transfer, $t$, where there are signs of this scaling that may potentially be observed at the EIC. Our results are represented as pseudo-data of vector meson production diffractive cross section and/or their ratios, which are obtained by parsing data collected by the event generator through smearing functions, emulating the proposed detector resolutions for the future EIC.

   ↳ nucl-thhep-phnucl-exEur.Phys.J.Plus(2023)·2 citations
4. 04*

   Production of $\psi (4040)$, $\psi (4160)$, and $\psi (4415)$ mesons in hadronic matter

   Li-Yuan Li🇨🇳 · Xiao-Ming Xu🇨🇳 · H. J. Weber🇺🇸

   We present the first study of production of $\psi (4040)$, $\psi (4160)$, and $\psi (4415)$ mesons in hadronic matter. Quark interchange between two colliding charmed mesons leads to the production of the three mesons. We calculate unpolarized cross sections for the reactions, $D\bar{D}\to \rho R$, $D{\bar{D}}^{\ast }\to \pi R$, $D{\bar{D}}^{\ast }\to \rho R$, $D^{\ast }\bar{D}\to \pi R$, $D^{\ast }\bar{D}\to \rho R$, $D^{\ast }{\bar{D}}^{\ast }\to \pi R$, and $D^{\ast }{\bar{D}}^{\ast }\to \rho R$, where $R$ stands for $\psi (4040)$, $\psi (4160)$, and $\psi (4415)$. In the temperature region covering hadronic matter the peak cross sections of producing $\psi (4040)$ are similar to or larger than the ones of producing $\psi (4415)$, and the latter are generally larger than those of producing $\psi (4160)$. With the cross sections we establish new master rate equations for $\psi (4040)$, $\psi (4160)$, and $\psi (4415)$. The equations are solved for central Pb-Pb collisions at $\sqrt{s_{NN}}=5.02$ TeV at the Large Hadron Collider. Solutions of the equations show that the $\psi (4040)$ number density at kinetic freeze-out of hadronic matter is larger than the $\psi (4415)$ number density which is larger than the $\psi (4160)$ number density.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2022)·2 citations
5. 05*

   Optimization of the first CUPID detector module

   CUPID collaboration: A. Armatol · C. Augier · F. T. Avignone III · O. Azzolini · M. Balata · K. Ballen · A. S. Barabash · G. Bari · A. Barresi · D. Baudin · F. Bellini · G. Benato and 165 other authors

   CUPID will be a next generation experiment searching for the neutrinoless double $\beta$ decay, whose discovery would establish the Majorana nature of the neutrino. Based on the experience achieved with the CUORE experiment, presently taking data at LNGS, CUPID aims to reach a background free environment by means of scintillating Li${}_2$${}^{100}$MoO${}_4$ crystals coupled to light detectors. Indeed, the simultaneous heat and light detection allows us to reject the dominant background of $\alpha$ particles, as proven by the CUPID-0 and CUPID-Mo demonstrators. In this work we present the results of the first test of the CUPID baseline module. In particular, we propose a new optimized detector structure and light sensors design to enhance the engineering and the light collection, respectively. We characterized the heat detectors, achieving an energy resolution of (5.9 $\pm$ 0.2) keV FWHM at the $Q$-value of ${}^{100}$Mo (about 3034 keV). We studied the light collection of the baseline CUPID design with respect to an alternative configuration which features gravity-assisted light detectors' mounting. In both cases we obtained an improvement in the light collection with respect to past measures and we validated the particle identification capability of the detector, which ensures an $\alpha$ particle rejection higher than 99.9%, fully satisfying the requirements for CUPID.

   ↳ physics.ins-detnucl-exEPJC(2022)·24 citations
6. 06*

   Evaluation of cosmogenic production of ${}^{39}Ar$ and ${}^{42}Ar$ for rare-event physics using underground argon

   Chao Zhang🇺🇸 · Dongming Mei🇺🇸

   Underground argon (UAr) with lower cosmogenic activities of ${}^{39}Ar$ and ${}^{42}Ar$ has been planned as a detector in detecting scintillation light and charge collection using time projection chambers for dark matter searches and as a veto detector in suppressing backgrounds for neutrinoless double beta decay (0$\nu \beta \beta$) experiments. Long-lived radioactive isotopes, ${}^{39}Ar$ and ${}^{42}Ar$, can also be produced on the surface when UAr is pumped out from a deep well. Understanding the production of long-lived isotopes in Ar is important for utilizing UAr for dark matter and 0$\nu \beta \beta$ experiments in terms of its production, transportation, and storage. Ar exposure to cosmic rays at sea-level is simulated using Geant4 for a given cosmic ray muon, neutron, and proton energy spectrum. We report the simulated cosmogenic production rates of ${}^{39}Ar$, ${}^{42}Ar$, and other long-lived isotopes at sea-level from fast neutrons, high energy muons, and high energy protons. Total production rates of 938.53/kg${}_{Ar}\cdot$day and 5.81$\times$10${}^{-3}$/kg${}_{Ar}\cdot$day for ${}^{39}$Ar and ${}^{42}$Ar are found from our simulation. Utilizing these production rates, we set a time limit of 954 days constrained by the production of ${}^{39}$Ar for UAr to be on the surface before it compromises the sensitivity for a dark matter experiment. Similarly, a time limit of 1702 days constrained by the production of ${}^{42}$Ar is found for a 0$\nu \beta \beta$ experiment.

   ↳ physics.ins-dethep-exnucl-exAstropart.Phys.(2022)·10 citations
7. 07*

   Asymmetric nuclear matter in relativistic mean-field models with isoscalar- and isovector-meson mixing

   Tsuyoshi Miyatsu🇰🇷 · Myung-Ki Cheoun🇰🇷 · Koichi Saito🇯🇵

   Using the relativistic mean-field model with nonlinear couplings between the isoscalar and isovector mesons, we study the properties of isospin-asymmetric nuclear matter. Not only the vector mixing, ${\omega }_{\mu }{\omega }^{\mu }{\rho }_{\nu }{\rho }^{\nu }$, but also the quartic interaction due to the scalar mesons, ${\sigma }^2{\delta }^2$, is taken into account to investigate the density dependence of nuclear symmetry energy, $E_{\mathrm{sym}}$, and the neutron-star properties. It is found that the $\delta$ meson increases $E_{\mathrm{sym}}$ at high densities, whereas the $\sigma$-$\delta$ mixing makes $E_{\mathrm{sym}}$ soft above the saturation density. Furthermore, the $\delta$ meson and its mixing have a large influence on the radius and tidal deformability of a neutron star. In particular, the $\sigma$-$\delta$ mixing reduces the neutron-star radius, and, thus, the present calculation can simultaneously reproduce the dimensionless tidal deformabilities of a canonical $1.4M_{\odot }$ neutron star observed from the binary neutron star merger, GW170817, and from the compact binary coalescence, GW190814.

   ↳ nucl-thastro-ph.HEnucl-exApJ(2022)·41 citations
8. 08*

   Transport Model Comparison Studies of Intermediate-Energy Heavy-Ion Collisions

   Hermann Wolter (1)🇩🇪 · Maria Colonna (2)🇮🇹 · Dan Cozma (3)🇷🇴 · Pawel Danielewicz (4,5)🇺🇸 · Che Ming Ko (6)🇺🇸 · Rohit Kumar (4)🇺🇸 · Akira Ono (7)🇯🇵 · ManYee Betty Tsang (4,5)🇺🇸 · Jun Xu (8,9)🇨🇳 · Ying-Xun Zhang (10,11)🇨🇳 · Elena Bratkovskaya (12,13)🇩🇪 · Zhao-Qing Feng (14)🇨🇳 and 40 other authors

   Transport models are the main method to obtain physics information from low to relativistic-energy heavy-ion collisions. The Transport Model Evaluation Project (TMEP) has been pursued to test the robustness of transport model predictions in reaching consistent conclusions from the same type of physical model. Calculations under controlled conditions of physical input and set-up were performed with various participating codes. These included both calculations of nuclear matter in a box with periodic boundary conditions, and more realistic calculations of heavy-ion collisions. In this intermediate review, we summarize and discuss the present status of the project. We also provide condensed descriptions of the 26 participating codes, which contributed to some part of the project. These include the major codes in use today. We review the main results of the studies completed so far. They show, that in box calculations the differences between the codes can be well understood and a convergence of the results can be reached. These studies also highlight the systematic differences between the two families of transport codes, known as BUU and QMD type codes. However, when the codes were compared in full heavy-ion collisions using different physical models, as recently for pion production, they still yielded substantially different results. This calls for further comparisons of heavy-ion collisions with controlled models and of box comparisons of important ingredients, like momentum-dependent fields, which are currently underway. We often indicate improved strategies in performing transport simulations and thus provide guidance to code developers. Results of transport simulations of heavy-ion collisions from a given code will have more significance if the code can be validated against benchmark calculations such as the ones summarized in this review.

   ↳ nucl-thnucl-exPPNP(2022)·161 citations
9. 09*

   Study of KNO scaling in pp collisions at $\sqrt{s}$ from 0.9 to 13 TeV using results of the ATLAS at the LHC

   Yuri Kulchitsky🇷🇺 · Pavel Tsiareshka (Joint Institute for Nuclear Research)🇷🇺

   The comparisons of the charged-particle multiplicity and the average transverse momentum distributions on the scaled multiplicity, KNO scale, using the results of the ATLAS collaboration at the LHC are presented. These distributions were measured in proton-proton collisions at centre-of-mass energies from 0.9 to 13 TeV for the absolute pseudorapidity region less than 2.5 and two samples of events with each charged-particle transverse momentum greater than 100 and 500 MeV, respectively. The shape evolution of the multiplicity distributions with a collision energy is studied in terms of KNO scaling variables. The charged-particle multiplicity distributions on the KNO scale have the similar shape and decrease with increasing collision energy. The KNO distributions tend to be independent of energy for the highest energies. The average transverse momentum distributions on the KNO scale have a similar shape and increase with increasing collision energy.

   ↳ hep-exnucl-exEPJC(2022)·10 citations
10. 10*

    CLAS12 Track Reconstruction with Artificial Intelligence

    Gagik Gavalian🇺🇸 · Polykarpos Thomadakis🇺🇸 · Angelos Angelopoulos🇺🇸 · Nikos Chrisochoides🇺🇸 · Raffaella De Vita🇮🇹 · Veronique Ziegler🇺🇸

    In this article we describe the implementation of Artificial Intelligence models in track reconstruction software for the CLAS12 detector at Jefferson Lab. The Artificial Intelligence based approach resulted in improved track reconstruction efficiency in high luminosity experimental conditions. The track reconstruction efficiency increased by $10-12\%$ for single particle, and statistics in multi-particle physics reactions increased by $15\%-35\%$ depending on the number of particles in the reaction. The implementation of artificial intelligence in the workflow also resulted in a speedup of the tracking by $35\%$.

    ↳ physics.data-annucl-ex6 citations
11. 11*

    Purity correction for cumulants of hyperon number distribution

    Toshihiro Nonaka🇯🇵

    We propose a purity correction to subtract effects of combinatorial backgrounds from cumulants of hyperon number distributions. We argue that cumulants and mix-cumulants of sidebands, whose yield is comparable with that of background particles in the signal region, can be used for the correction. The method is demonstrated in a simple toy model by introducing effects of reconstruction efficiencies and backgrounds. We show that topological cut parameters for hyperon reconstructions can be optimized to achieve the best statistical significance after purity and efficiency corrections. The method will enable us to measure cumulants of net-baryon, net-strangenss, and their correlations with better figure of merit than the conventional approach.

    ↳ hep-phhep-exnucl-exphysics.data-anNucl.Instrum.Meth.A(2022)·5 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.