Nuclear Theory·nucl-th

Thursday·June 27, 2019

12 papers—7 primary·5 cross-listed

01
[Submitted on 25 Jun 2019]
DAB-MOD sensitivity study of heavy flavor $R_{AA}$ and azimuthal anisotropies based on beam energy, initial conditions, hadronization, and suppression mechanisms
Roland Katz🇫🇷 · Caio A. G. Prado🇨🇳 · Jacquelyn Noronha-Hostler🇺🇸 · Jorge Noronha🇧🇷 · Alexandre A. P. Suaide🇧🇷
Heavy flavor probes provide important information about the in-medium properties of the quark-gluon plasma produced in heavy-ion collisions. In this work, we investigate the effects of 2D+1 event-by-event fluctuating hydrodynamic backgrounds on the nuclear suppression factor and momentum anisotropies of heavy flavor mesons and non-photonic electrons. Using the state-of-the-art D and B mesons modular simulation code (called "DAB-MOD"), we perform a systematic comparison of different transport equations in the same background, including a few energy loss models --- with and without energy loss fluctuations --- and a relativistic Langevin model with different drag parametrizations. We present the resulting D and B mesons $R_{AA}$ , $v_{2}$ , $v_{3}$ , and $v_{4}$ as well as multi-particle cumulants, in AuAu collisions at $s_{NN} = 200 GeV$ and PbPb collisions at $s_{NN} = 2.76 TeV$ and $s_{NN} = 5.02 TeV$ , and compare them to the available experimental data. The $v_{2} {4} / v_{2} {2}$ ratio, which is known to be a powerful probe of the initial conditions and flow fluctuations in the soft sector, is also studied in the context of heavy flavor. We also investigate the correlations between the transverse anisotropies of heavy mesons and all charged particles to better understand how heavy quarks couple to the hydrodynamically expanding quark-gluon plasma. We study the influence that different initial conditions and the implementation of heavy-light quark coalescence has on our results.
Comments:
52 pages
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1906.10768 [pdf]
PRC(2020)·61 citations
02
[Submitted on 26 Jun 2019]
Level inversion in kaonic nuclei and the high-density nuclear equation of state
Rong-Yao Yang🇨🇳 · Wei-Zhou Jiang🇨🇳 · Si-Na Wei🇨🇳
It is very difficult for any nuclear model to pin down the saturation property and high-density equation of state (EOS) simultaneously because of high nonlinearity of the nuclear many-body problem. In this work, we propose, for the first time, to use the special property of light kaonic nuclei to characterize the relation between saturation property and high-density EOS. With a series of relativistic mean-field models, this special property is found to be the level inversion between orbitals $2 S_{1/2}$ and $1 D_{5/2}$ in light kaonic nuclei. This level inversion can serve as a theoretical laboratory to group the incompressibility at saturation density and the EOS at supra-normal densities simultaneously.
Comments:
10 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1906.10868 [pdf]
PLB(2019)·4 citations
03
[Submitted on 26 Jun 2019]
The gallium anomaly revisited
Joel Kostensalo🇫🇮 · Jouni Suhonen🇫🇮 · Carlo Giunti🇮🇹 · Praveen C. Srivastava🇮🇳
The gallium anomaly, i.e. the missing electron-neutrino flux from $^{37}$ Ar and $^{51}$ Cr electron-capture decays as measured by the GALLEX and SAGE solar-neutrino detectors, has been among us already for about two decades. We present here a new estimate of the significance of this anomaly based on cross-section calculations using nuclear shell-model wave functions obtained by exploiting recently developed two-nucleon interactions. The gallium anomaly of the GALLEX and SAGE experiments is found to be smaller than that obtained in previous evaluations, decreasing the significance from 3.0 $σ$ to 2.3 $σ$ . This result is compatible with the recent indication in favor of short-baseline $ν ˉ_{e}$ disappearance due to small active-sterile neutrino mixing obtained from the combined analysis of the data of the NEOS and DANSS reactor experiments.
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1906.10980 [pdf]
PLB(2019)·100 citations
04
[Submitted on 25 Jun 2019]
Equation of State of Hot Dense Hyperonic Matter in the Quark-Meson-Coupling (QMC-A) model
J.R.Stone🇺🇸 · V.Dexheimer🇺🇸 · P.A.M.Guichon🇫🇷 · A.W.Thomas🇦🇺 · S.Typel🇩🇪
We report a new equation of state (EoS) of cold and hot hyperonic matter constructed in the framework of the quark-meson-coupling (QMC-A) model. The QMC-A EoS yields results compatible with available nuclear physics constraints and astrophysical observations. It covers the range of temperatures from T=0 to 100 MeV, entropies per particle S/A between 0 and 6, lepton fractions from Y $_{L}$ =0.0 to 0.6, and baryon number densities n $_{B}$ =0.05-1.2 fm $^{- 3}$ . Applications of the QMC-A EoS are made to cold neutron stars (NS) and to hot proto-neutron stars (PNS) in two scenarios, (i) lepton rich matter with trapped neutrinos and (ii) deleptonized chemically equilibrated matter. We find that the QMC-A model predicts hyperons in amounts growing with increasing temperature and density, thus suggesting not only their presence in PNS but also, most likely, in NS merger remnants. The nucleon-hyperon phase transition is studied through the adiabatic index and the speed of sound c $_{s}$ . It is shown that the lowering of (c $_{s}$ /c) $^{2}$ to and below the conformal limit of 1/3 is a general consequence of instabilities due to any phase transition and is not a unique fingerprint of the hadron-quark matter transition. Rigid rotation of cold and hot stars, their moments of inertia and Kepler frequencies are also explored. The QMC-A model results are compared with two relativistic models, the chiral mean field model (CMF), and the generalized relativistic density functional with hyperons (GRDF-Y). Similarities and differences are discussed.
Comments:
14 pages, 14 figures. Final version accepted for publication in MNRAS 2020 December 17
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
arXiv:
1906.11100 [pdf]
MNRAS(2021)·81 citations
05
[Submitted on 26 Jun 2019]
Cascade and Omega productions from Pb+Pb Collisions at LHC energy
Purabi Ghosh🇮🇳 · Jajati K. Nayak🇮🇳 · Sushant K. Singh🇮🇳 · Santosh K. Agarwalla🇮🇳
Production of multi strange hadrons like cascade ( $Ξ$ ) and omega( $Ω$ ) baryons are studied microscopically using rate equation at $s_{N N}$ =2.76 TeV, Large Hadron Collider(LHC) energy. The rate equations for $Ξ$ , $Ω$ are solved simultaneously with other strange hadrons in an expanding medium. The results for $Ξ$ and $Ω$ are compared with the data obtained from Pb-Pb collisions at $s_{N N}$ = 2.76 TeV from ALICE experiments. The ratio of yields of $Ξ$ and $Ω$ to $π$ are analysed with various initial conditions and compared with the experimental observations made for various charge particle multiplicities.
Comments:
7 pages, 8 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1906.11115 [pdf]
3 citations
06
[Submitted on 26 Jun 2019]
(3+1)-dimensional dissipative relativistic fluid dynamics at non-zero net baryon density
Lipei Du🇺🇸 · Ulrich Heinz🇺🇸
Heavy-ion collisions at center-of-mass energies between 1 and 100 GeV/nucleon are essential to understand the phase diagram of QCD and search for its critical point. At these energies the net baryon density of the system can be high, and simulating its evolution becomes an indispensable part of theoretical modeling. We here present the (3+1)-dimensional diffusive relativistic hydrodynamic code BEShydro which solves the equations of motion of second-order Denicol-Niemi-Molnar-Rischke (DNMR) theory, including bulk and shear viscous currents and baryon diffusion currents. BEShydro features a modular structure that allows to easily turn on and off baryon evolution and different dissipative effects and thus to study their physical effects on the dynamical evolution individually. An extensive set of test protocols for the code, including several novel tests of the precision of baryon transport that can also be used to test other such codes, is documented here and supplied as a permanent part of the code package.
Comments:
62 pages, 8 figures; small changes, accepted version
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Computational Physics (physics.comp-ph)
arXiv:
1906.11181 [pdf]
Comput.Phys.Commun.(2020)·98 citations
07
[Submitted on 26 Jun 2019]
Collective treatment of the isovector pair correlations. Boson representation
G. Nikoghosyan · E. A. Kolganova · D. A. Sazonov · R. V. Jolos
The theoretical approach to consideration of the Hamiltonian with pairing forces using a technique of the finite boson representation is developed. It is shown that a simultaneous description of the pairing vibrational state in $^{56}$ Ni and the pairing rotational states with $T$ =0 in the neighboring $N = Z$ nuclei is possible if the pairing Hamiltonian takes into account only isovector monopole pairing. However, the calculated energies of the pairing rotational states of $N = Z$ nuclei removed from $^{56}$ Ni by 12 and more nucleons exceed significantly the experimental values. The possible reason of this discrepancy is discussed.
Comments:
16 pages, 2 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1906.11232 [pdf]
EPJA(2019)·2 citations
08
[Submitted on 26 Jun 2019] (cross-list from hep-ph)
Bounce Configuration from Gradient Flow
So Chigusa🇯🇵 · Takeo Moroi🇯🇵 · Yutaro Shoji🇯🇵
Based on the gradient flow, we propose a new method to determine the bounce configuration for false vacuum decay. Our method is applicable to a large class of models with multiple fields. Since the bounce is a saddle point of an action, a naive gradient flow method which minimizes the action does not work. We point out that a simple modification of the flow equation can make the bounce its stable fixed point while the false vacuum configuration an unstable one. Consequently, the bounce configuration can be obtained simply by following the flow without a careful choice of an initial configuration. With numerical analysis, we confirm the validity of our claim, checking that the flow equation we propose indeed has solutions that flow into the bounce configuration.
Comments:
6 pages, 2 figures; published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1906.10829 [pdf]
PLB(2020)·29 citations
09
[Submitted on 26 Jun 2019] (cross-list from hep-ph)
A note on scalar meson dominance
Y. Ünal🇩🇪 · Ulf-G. Meißner🇩🇪
We consider chiral perturbation theory with an explicit broad $σ$ -meson and study its contribution to the scalar form factors of the pion and the nucleon. Our goal is to learn more about resonance saturation in the scalar sector.
Comments:
9 pages, 3 figures, extended introduction and discussions, conclusions unchanged, version accepted for publication in Chinese Physics C
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1906.10961 [pdf]
CPC(2019)·0 citations
10
[Submitted on 26 Jun 2019] (cross-list from hep-ph)
Neutron spin structure from polarized deuteron DIS with proton tagging
W. Cosyn🇧🇪 · C. Weiss🇺🇸
Polarized electron-deuteron deep-inelastic scattering (DIS) with detection of the spectator proton ("tagged DIS") enables measurements of neutron spin structure with maximal control of nuclear effects. We calculate the longitudinal spin asymmetries in polarized tagged DIS using methods of light-front nuclear structure and study their dependence on the measured proton momentum. Asymmetries can be formed with all three deuteron spin states ( $\pm 1, 0$ ) or the two maximum-spin states only ( $\pm 1$ , involving tensor polarization). The proton momentum dependence can be used to select pure S-wave configurations in the deuteron and eliminate D-wave depolarization (transverse momenta $p_{pT} ≲$ 100 MeV). Free neutron spin structure can be extracted model-independently through pole extrapolation of the tagged asymmetries. Such measurements could be performed at a future electron-ion collider (EIC) with polarized deuteron beams and forward proton detectors.
Comments:
7 pages, 3 figures. Revised published version; minor additions in the text
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1906.11119 [pdf]
PLB(2019)·10 citations
11
[Submitted on 26 Jun 2019] (cross-list from hep-ph)
Radial oscillations of quark stars from perturbative QCD
José C. Jiménez🇧🇷 · Eduardo S. Fraga🇧🇷
We perform the general relativistic stability analysis against radial oscillations of unpaired quark stars obtained using the equation of state for cold quark matter from perturbative QCD, the only free parameter being the renormalization scale. This approach consistently incorporates the effects of interactions and includes a built-in estimate of the inherent systematic uncertainties in the evaluation of the equation of state. We also take into account the constraints imposed by the recent gravitational wave event GW 170817 to the compact star masses and radii, and restrict their vibrational spectrum.
Comments:
10 pages, 5 figures; v2: figures added, references added, modifications to the text
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
1906.11189 [pdf]
PRD(2019)·23 citations
12
[Submitted on 26 Jun 2019] (cross-list from hep-lat)
Gluon Field Digitization for Quantum Computers
Andrei Alexandru🇺🇸 · Paulo F. Bedaque🇺🇸 · Siddhartha Harmalkar🇺🇸 · Henry Lamm🇺🇸 · Scott Lawrence🇺🇸 · Neill C. Warrington (for the NuQS Collaboration)🇺🇸
Simulations of gauge theories on quantum computers require the digitization of continuous field variables. Digitization schemes that uses the minimum amount of qubits are desirable. We present a practical scheme for digitizing $S U (3)$ gauge theories via its discrete subgroup $S (1080)$ . The $S (1080)$ standard Wilson action cannot be used since a phase transition occurs as the coupling is decreased, well before the scaling regime. We proposed a modified action that allows simulations in the scaling window and carry out classical Monte Carlo calculations down to lattice spacings of order $a \approx 0.08$ fm. We compute a set of observables with sub-percent precision at multiple lattice spacings and show that the continuum extrapolated value agrees with the full $S U (3)$ results. This suggests that this digitization scheme provides sufficient precision for NISQ-era QCD simulations.
Comments:
5 pages, 5 figures
Subjects:
High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th); Computational Physics (physics.comp-ph); Quantum Physics (quant-ph)
arXiv:
1906.11213 [pdf]
PRD(2019)·163 citations

Affiliations

first authorsco-authorsvia INSPIRE