Mon·Feb 17, 2020Monday·February 17, 2020

1. 01*

   A New Heavy Flavor Program for the Future Electron-Ion Collider

   Xuan Li🇺🇸 · Ivan Vitev🇺🇸 · Melynda Brooks🇺🇸 · Lukasz Cincio🇺🇸 · J. Matthew Durham🇺🇸 · Michael Graesser🇺🇸 · Ming X. Liu🇺🇸 · Astrid Morreale🇺🇸 · Duff Neill🇺🇸 · Cesar da Silva🇺🇸 · Walter E. Sondheim🇺🇸 · Boram Yoon🇺🇸

   The proposed high-energy and high-luminosity Electron-Ion Collider (EIC) will provide one of the cleanest environments to precisely determine the nuclear parton distribution functions (nPDFs) in a wide $x$-$Q^2$ range. Heavy flavor production at the EIC provides access to nPDFs in the poorly constrained high Bjorken-$x$ region, allows us to study the quark and gluon fragmentation processes, and constrains parton energy loss in cold nuclear matter. Scientists at the Los Alamos National Laboratory are developing a new physics program to study heavy flavor production, flavor tagged jets, and heavy flavor hadron-jet correlations in the nucleon/nucleus going direction at the future EIC. The proposed measurements will provide a unique way to explore the flavor dependent fragmentation functions and energy loss in a heavy nucleus. They will constrain the initial-state effects that are critical for the interpretation of previous and ongoing heavy ion measurements at the Relativistic Heavy Ion Collider and the Large Hadron Collider. We show an initial conceptual design of the proposed Forward Silicon Tracking (FST) detector at the EIC, which is essential to carry out the heavy flavor measurements. We further present initial feasibility studies/simulations of heavy flavor hadron reconstruction using the proposed FST.

   nucl-exhep-exhep-phnucl-thEPJ Web Conf.(2020)·23 citations
2. 02*

   The Hoyle Family: The search for alpha-condensate states in light nuclei

   R. Smith🇬🇧 · J. Bishop🇺🇸 · J. Hirst · Tz. Kokalova🇬🇧 · C. Wheldon🇬🇧

   Our present understanding of the structure of the Hoyle state in ${}^{12}$C and other near-threshold states in $\alpha$-conjugate nuclei is reviewed in the framework of the $\alpha$-condensate model. The ${}^{12}$C Hoyle state, in particular, is a candidate for $\alpha$-condensation, due to its large radius and $\alpha$-cluster structure. The predicted features of nuclear $\alpha$-particle condensates are reviewed along with a discussion of their experimental indicators, with a focus on precision break-up measurements. Two experiments are discussed in detail, firstly concerning the break-up of ${}^{12}$C and then the decays of heavier nuclei. With more theoretical input, and increasingly complex detector setups, precision break-up measurements can, in principle, provide insight into the structures of states in $\alpha$-conjugate nuclei. However, the commonly-held belief that the decay of a condensate state will result in $N$ $\alpha$-particles is challenged. We further conclude that unambiguously characterising excited states built on $\alpha$-condensates is difficult, despite improvements in detector technology.

   nucl-exnucl-thFew Body Syst.(2020)·8 citations
3. 03*

   Robustness of principal component analysis on harmonic flow in heavy ion collisions

   Ziming Liu🇨🇳 · Arabinda Behera🇺🇸 · Huichao Song🇨🇳 · Jiangyong Jia🇺🇸

   The principal component analysis (PCA), a mathematical tool commonly used in statistics, has recently been employed to interpret the $p_T$-dependent fluctuations of harmonic flow $v_n$ in terms of leading and subleading flow modes in heavy ion collisions. Using simulated data from AMPT and HIJING models, we show that the PCA modes are not fixed, but depend on the choice of the particle weight and the $p_T$ range. Furthermore, the shape of the leading mode is affected by the presence of non-flow correlations, and fake subleading mode may arise from the mixing of non-flow correlations with leading flow mode with a magnitude that could be larger than the genuine subleading flow mode. Therefore, the meaning of PCA modes and their relations to physical leading and subleading flow modes associated initial state eccentricities need to be further clarified/validated in realistic model simulations.

   nucl-exhep-phPRC(2020)·12 citations
4. 04*

   Kinetic characteristics of ions in an inertial electrostatic confinement device

   D. Bhattacharjee · S. Adhikari🇺🇸 · N. Buzarbaruah · S. R. Mohanty

   The kinetic analyses are quite important when it comes to understand the particle behavior in any device as they start to deviate from continuum nature. In the present study, kinetic simulations are performed using Particle-in-Cell (PIC) method to analyze the behavior of ions inside a cylindrical Inertial Electrostatic Confinement Fusion (IECF) device which is being developed as a tabletop neutron source. Here, the lighter ions, like deuterium are accelerated by applying an electrostatic field between the chamber wall (anode) and the cathode (cylindrical gridded wire), placed at the center of the device. The plasma potential profiles obtained from the simulated results indicate the formation of multiple potential well structures inside the cathode grid depending upon the applied cathode potential (from $-1$ to $-5kV$). The ion density at the core region of the device is found to be of the order of $10^{16}{m}^{-3}$, which closely resembles the experimental observations. Spatial variation of Ion Energy Distribution Function (IEDF) has been measured in order to observe the characteristics of ions at different cathode voltages. Finally, the simulated results are compared and found to be in good agreement with the experimental profiles. The present analysis can serve as a reference guide to optimize the technological parameters of the discharge process in IECF devices.

   ↳ physics.plasm-phnucl-exphysics.atom-phPRE(2020)·1 citation
5. 05*

   Electromagnetic transition form factors, $E2/M1$ and $C2/M1$ ratios of the baryon decuplet

   June-Young Kim🇩🇪 · Hyun-Chul Kim🇰🇷

   We investigate the electromagnetic transition form factors of the baryon decuplet to the baryon octet, based on the self-consistent SU(3) chiral quark-soliton model, taking into account the effects of explicit breaking of flavor SU(3) symmetry. We emphasize the $Q^2$ dependence of the electromagnetic $N\to \Delta$ transition form factors and the ratios of $E2/M1$ and $C2/M1$ in comparison with the experimental and empirical data. In order to compare the present results of the electromagnetic transition form factors of the $N\to \Delta$ with those from lattice QCD, we evaluate the form factors with the pion mass deviated from its physical value. The results of the $E2/M1$ and $C2/M1$ ratios are in good agreement with the lattice data. We also present the results of the electromagnetic transition form factors for the decuplet to the octet transitions.

   ↳ hep-phhep-exhep-latnucl-exEPJC(2020)·14 citations
6. 06*

   Clustering structure effect on Hanbury-Brown-Twiss correlation in ${}^{12}$C + ${}^{197}$Au collisions at 200 GeV}

   Junjie He🇨🇳 · Song Zhang🇨🇳 · Yu-Gang Ma🇨🇳 · Jinhui Chen🇨🇳 · Chen Zhong🇨🇳

   Through ${}^{12}$C + ${}^{197}$Au collisions at $\sqrt{s_{NN}}=$ 200 GeV using a multiphase transport (AMPT) model, the azimuthal angle dependences of the Hanbury Brown-Twiss (HBT) radii relative to the second- and third-order participant plane from $\pi$-$\pi$ correlations are discussed. Three initial geometric configurations of ${}^{12}$C, namely three-$\alpha$-cluster triangle, three-$\alpha$-cluster chain and Woods-Saxon distribution of nucleons, are taken into account, and their effects on the correlations are investigated. The ratio of the third- to the second-order HBT radii $R_{o(s),3}^2/R_{o(s),2}^2$ is shown to be a clear probe for three configurations. In addition, this work presents the hadronic rescattering time evolution of the azimuthally dependent HBT radii. From the present study, one can learn that the HBT correlation from identical particles at freeze-out is able to provide the information of different initial configurations as collective flow proposed before.

   ↳ nucl-thnucl-exEPJA(2020)·25 citations
7. 07*

   Nucleon-number scalings of anisotropic flows and nuclear modification factor for light nuclei in the squeeze-out region

   T. T. Wang🇨🇳 · Y. G. Ma🇨🇳

   The number of nucleon (NN) scaling of the directed flow $v_1$ and elliptic flow ($v_2$) as well as the nuclear modification factor ($R_{cp}$) are tested for light nuclei which are produced in 0.4$A$ GeV ${}^{197}Au{+}^{197}Au$ collisions at different impact parameters with two different in-medium nucleon-nucleon cross sections in the framework of an isospin-dependent quantum molecular dynamics (IQMD) model. In that energy domain, the emission of light nuclei can be well described by the squeeze-out phenonomenon. The results show a nice NN scaling behavior for flow parameters $v_1$, $v_2$ and $R_{cp}$. These results demonstrate that the nucleon coalescence mechanism is responsible for nucleon-number scaling of above physical observables in squeeze-out region in heavy-ion collisions at intermediate energy.

   ↳ nucl-thnucl-exEPJA(2019)·10 citations
8. 08*

   Correlation Measurements of Charged Particles and Jets at Mid-Rapidity with Event Activity at Backward-Rapidity in $\sqrt{s_{\mathrm{NN}}}=200\mathrm{GeV}$ $p$+Au Collisions at STAR

   David Stewart🇺🇸

   Semi-inclusive charged jet spectra per trigger at STAR are presented binned by event activity (EA) as determined by the Beam Beam Counter (BBC) signal in the Au-going direction. The selected EA determination is motivated by correlations between the number of charged tracks in the Time Projection Chamber (TPC) ($|\eta |<1$) and EA (${\eta }_{\mathrm{EA}}\in [-5,-2]$) which are also presented. The jet spectra per trigger at high EA are suppressed relative to the spectra at low EA. A PYTHIA investigation refutes that the suppression results from a trivial autocorrelation between jet kinematics and the acceptance of the EA and the TPC.

   ↳ hep-exnucl-exNPA(2021)·1 citation

* 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.