Fri·Jul 24, 2020Friday·July 24, 2020

1. 01*

   Evidence of Coalescence Sum Rule in Elliptic Flow of Identified Particles in High-energy Heavy-ion Collisions

   Amir Goudarzi🇺🇸 · Gang Wang🇺🇸 · Huan Zhong Huang🇺🇸

   The major goal of high-energy heavy-ion collisions is to study the properties of the deconfined quark gluon plasma (QGP), such as partonic collectivity. The collective motion of constituent quarks can be derived from the anisotropic flow measurements of identified hadrons within the coalescence framework. Based on published results of elliptic flow ($v_2$), we shall test the coalescence sum rule using $K^{\pm }$, $p$, $\bar{p}$, $\Lambda$ and $\bar{\Lambda }$, and further extract $v_2$ values for produced $u$($d$, $\bar{u}$, $\bar{d}$), $s$ and $\bar{s}$ quarks, as well as transported $u(d)$ quarks in 10-40\% Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=$ 7.7, 11.5, 14.5, 19.6, 27, 39 and 62.4 GeV. We also attempt to link the $v_2$ difference between ${\pi }^{-}$ and ${\pi }^{+}$ to the different numbers of $u$ and $d$ quarks in the initial gold ions, and to relate the $v_2$ measurements of multi-strange hadrons to the formation times of $\varphi$, ${\Omega }^{\pm }$ and ${\Xi }^{+}$.

   nucl-exhep-exPLB(2020)·5 citations
2. 02*

   In-beam $\gamma$-ray spectroscopy at the proton dripline: ${}^{40}$Sc

   A. Gade🇺🇸 · D. Weisshaar🇺🇸 · B. A. Brown🇺🇸 · J. A. Tostevin🇬🇧 · D. Bazin🇺🇸 · K. Brown🇺🇸 · R. J. Charity🇺🇸 · P. J. Farris · A. M. Hill · J. Li🇨🇳 · B. Longfellow🇺🇸 · W. Reviol🇺🇸 · D. Rhodes🇺🇸

   We report on the first in-beam $\gamma$-ray spectroscopy of the proton-dripline nucleus ${}^{40}$Sc using two-nucleon pickup onto an intermediate-energy rare-isotope beam of ${}^{38}$Ca. The ${}^9$Be(${}^{38}$Ca,${}^{40}$Sc$+\gamma$)X reaction at 60.9 MeV/nucleon mid-target energy selectively populates states in ${}^{40}$Sc for which the transferred proton and neutron couple to high orbital angular momentum. In turn, due to angular-momentum selection rules in proton emission and the nuclear structure and energetics of ${}^{39}$Ca, such states in ${}^{40}$Sc then exhibit $\gamma$-decay branches although they are well above the proton separation energy. This work uniquely complements results from particle spectroscopy following charge-exchange reactions on ${}^{40}$Ca as well as ${}^{40}$Ti EC/${\beta }^{+}$ decay which both display very different selectivities. The population and $\gamma$-ray decay of the previously known first $(5^{-})$ state at 892 keV and the observation of a new level at 2744 keV are discussed in comparison to the mirror nucleus and shell-model calculations. On the experimental side, this work shows that high-resolution in-beam $\gamma$-ray spectroscopy is possible with new generation Ge arrays for reactions induced by rare-isotope beams on the level of a few $\mu$b of cross section.

   nucl-exPLB(2020)·8 citations
3. 03*

   Parameterizing Smooth Viscous Fluid Dynamics With a Viscous Blast Wave

   Zhidong Yang🇺🇸 · Rainer J. Fries🇺🇸

   Blast wave fits are widely used in high energy nuclear collisions to capture essential features of global properties of systems near kinetic equilibrium. They usually provide temperature fields and collective velocity fields on a given hypersurface. We systematically compare blast wave fits of fluid dynamic simulations for Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV and Pb+Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV with the original simulations. In particular, we investigate how faithful the viscous blast wave introduced in \cite{Yang:2022yxa} can reproduce the given temperature and specific shear viscosity fixed at freeze-out of a viscous fluid dynamic calculation, if the final spectrum and elliptic flow of several particle species are fitted. We find that viscous blast wave fits describe fluid dynamic pseudodata rather well and reproduce the specific shear viscosities to good accuracy. However, extracted temperatures tend to be underpredicted, especially for peripheral collisions. We investigate possible reasons for these deviations. We establish maps from true to fitted values. These maps can be used to improve raw fit results from viscous blast wave fits. Although our work is limited to two specific, albeit important, parameters and two collision systems, the same procedure can be easily generalized to other parameters and collision systems.

   ↳ nucl-thnucl-exJ.Phys.G(2024)·13 citations
4. 04*

   The conceptual design of the miniBeBe detector proposed for NICA-MPD

   Ramón Acevedo Kado🇲🇽 · Mauricio Alvarado Hernández🇲🇽 · Alejandro Ayala🇲🇽 · Marco Alberto Ayala Torres🇲🇽 · Wolfgang Bietenholz🇲🇽 · Dario Chaires🇲🇽 · Eleazar Cuautle🇲🇽 · Isabel Domínguez🇲🇽 · Alejandro Guirado🇲🇽 · Ivonne Maldonado🇲🇽 · Julio Maldonado🇲🇽 · Eduardo Moreno-Barbosa🇲🇽 and 10 other authors

   We present the conceptual design for the miniBeBe detector proposed to be installed as a level-0 trigger for the TOF of the NICA-MPD. We discuss the design and the geometrical array of its sensitive parts, the read-out electronics as well as the mechanical support that is envisioned. We also present simulation results for p + p and Bi + Bi collisions to study its capabilities as a function of multiplicity both as a level-0 trigger for the TOF, as well as to serve as a beam-gas interaction veto and to locate the beam-beam interaction vertex.

   ↳ physics.ins-dethep-exnucl-exJINST(2021)·8 citations
5. 05*

   Temperature evolution of the nuclear shell structure and the dynamical nucleon effective mass

   Herlik Wibowo🇺🇸 · Elena Litvinova🇺🇸 · Yinu Zhang🇺🇸 · Paolo Finelli🇮🇹

   We study the fermionic Matsubara Green functions in medium-mass nuclei at finite temperature. The single-fermion Dyson equation with the dynamical kernel of the particle-vibration-coupling (PVC) origin is formulated and solved in the basis of Dirac spinors, which minimize the grand canonical potential with the meson-nucleon covariant energy density functional. The PVC correlations beyond mean field are taken into account in the leading approximation for the energy-dependent self-energy, and the full solution of the finite-temperature Dyson equation is obtained for the fermionic propagators. Within this approach, we investigate the fragmentation of the single-particle states and its evolution with temperature for the nuclear systems ${}^{56,68}$Ni and ${}^{56}$Fe relevant for the core-collapse supernova. The energy-dependent, or dynamical, nucleon effective mass is extracted from the PVC self-energy at various temperatures.

   ↳ nucl-thnucl-exPRC(2020)·4 citations
6. 06*

   On feasibility of azimuthal flow studies with Principal Component Analysis

   Igor Altsybeev🇷🇺

   It is shown that the Principal Component Analysis applied to azimuthal single-particle distributions allows to perform flow analysis in ways that are analogous to the traditional approaches based on multi-particle correlations. In particular, symmetric cumulants are considered. It is demonstrated also that statistical fluctuations due to a finite number of particles per event practically do not play a role for higher order PCA-based cumulants.

   ↳ nucl-thnucl-exJ.Phys.Conf.Ser.(2020)·0 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.