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Nuclear Theory·nucl-th

Monday·October 28, 2019

6 papers—2 primary·4 cross-listed

All6Primary2Cross-lists4
  1. 01

    [Submitted on 25 Oct 2019]

    Third order viscous hydrodynamics from the entropy four current

    Mohammed Younus🇿🇦 · Azwinndini Muronga🇿🇦

    Non-equilibrium dynamics for relativistic fluid or quark gluon plasma (QGP) have already been calculated earlier upto third order using both kinetic and thermodynamic approaches. Calculations presented in this manuscript are based on thermodynamics principles. The expressions for third order dissipative fluxes have been derived from equation for entropy 4-current developed earlier by A. Muronga. The relaxation equations in the present work have been developed in a simple Bjorken (1+1)D scenario and Eckart frame. The relaxation equations are found to have slightly different values for the coupling coefficients as compared to calculations from earlier models. The solutions to the differential equations have been found to be sensitive to values of these coefficients. The shear relaxation equations derived in third order theory are discussed term by term. Effects of third order theory on shear relaxation time has been discussed. Thermodynamic quantities related to hot and dense matter have been calculated as functions of proper time. Moreover, various initial conditions for the relaxation equations have been assumed to study their effects on above mentioned observables. A LHC QGP formation time of = 0.4 fm/c and temperature of T = 500 MeV have been assumed.

    Comments:
    15 pages, 16 figures (Fig. 6 is with two plots)
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1910.11735 [pdf]
    PRC(2020)·9 citations
  2. 02

    [Submitted on 25 Oct 2019]

    The properties of neutron star from realistic nucleon-nucleon interaction within relativistic Hartree-Fock model

    Ying Zhang · Peng Liu · Jinniu Hu

    The properties of neutron star are studied in the framework of relativistic Hartree-Fock (RHF) model with realistic nucleon-nucleon () interactions, i.e. Bonn potentials. The strong repulsion of interaction at short range is properly removed by the unitary correlation operator method (UCOM). Meanwhile, the tensor correlation is neglected due to the very rich neutron environment in neutron star, where the total isospin of two nucleons can be approximately regarded as . The equations of state of neutron star matter are calculated in equilibrium and charge neutrality conditions. The properties of neutron star, such as mass, radius, and tidal deformability are obtained by solving the Tolman-Oppenheimer-Volkoff equation and tidal equation. The maximum masses of neutron from Bonn A, B, C potentials are around . The radius are km at , respectively. The corresponding tidal deformabilities are . All of these properties are satisfied the recent observables from the astronomical and gravitational wave devices and are consistent with the results from the relativistic Brueckner-Hartree-Fock model.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1910.11765 [pdf]
    IJMPE(2020)·2 citations
  3. 03

    [Submitted on 24 Oct 2019] (cross-list from hep-ph)

    TMD Soft Function from Large-Momentum Effective Theory

    Xiangdong Ji🇨🇳 · Yizhuang Liu🇨🇳 · Yu-Sheng Liu🇨🇳

    We study Euclidean formulations of the transverse-momentum-dependent (TMD) soft function, which is a cross section for soft gluon radiations involving color charges moving in two conjugate lightcone directions in quantum chromodynamics. We show it is related to a special form factor of a pair of color sources traveling with nearly-lightlike velocities, which can be matched to TMD physical observables in semi-inclusive deep-inelastic scattering and Drell-Yan process in the framework of large momentum effective theory. It can also be extracted by combining a large-momentum form factor of light meson and its leading TMD wave function. These formulations are useful for initiating nonperturbative calculations of this useful quantity.

    Comments:
    5 pages, 1 figure
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1910.11415 [pdf]
    NPB(2020)·106 citations
  4. 04

    [Submitted on 24 Oct 2019] (cross-list from hep-ph)

    Jet angularities in photoproduction at the Electron-Ion Collider

    Elke-Caroline Aschenauer🇺🇸 · Kyle Lee🇺🇸 · B.S. Page🇺🇸 · Felix Ringer🇺🇸

    We consider the one-parameter family of jet substructure observables known as angularities using the specific case of inclusive jets arising from photoproduction events at an Electron-Ion Collider (EIC). We perform numerical calculations at next-to-leading logarithmic accuracy within perturbative QCD and compare our results to PYTHIA 6 predictions. Overall, we find good agreement and conclude that jet substructure observables are feasible at the EIC despite the relatively low jet transverse momentum and particle multiplicities. We investigate the size of subleading power corrections relevant at low energies within the Monte Carlo setup. In order to establish the validity of the Monte Carlo tune, we also perform comparisons to jet shape data at HERA. We further discuss detector requirements necessary for angularity measurements at an EIC, focusing on hadron calorimeter energy and spatial resolutions. Possible applications of precision jet substructure measurements at the EIC include the tuning of Monte Carlo event generators, the extraction of nonperturbative parameters and studies of cold nuclear matter effects.

    Comments:
    12 pages, 8 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1910.11460 [pdf]
    PRD(2020)·49 citations
  5. 05

    [Submitted on 25 Oct 2019] (cross-list from hep-ph)

    Identifying the nature of the QCD transition in relativistic collision of heavy nuclei with deep learning

    Yi-Lun Du🇩🇪 · Kai Zhou🇩🇪 · Jan Steinheimer🇩🇪 · Long-Gang Pang🇺🇸 · Anton Motornenko🇩🇪 · Hong-Shi Zong🇨🇳 · Xin-Nian Wang🇺🇸 · Horst Stöcker🇩🇪

    Using deep convolutional neural network (CNN), the nature of the QCD transition can be identified from the final-state pion spectra from hybrid model simulations of heavy-ion collisions that combines a viscous hydrodynamic model with a hadronic cascade "after-burner". Two different types of equations of state (EoS) of the medium are used in the hydrodynamic evolution. The resulting spectra in transverse momentum and azimuthal angle are used as the input data to train the neural network to distinguish different EoS. Different scenarios for the input data are studied and compared in a systematic way. A clear hierarchy is observed in the prediction accuracy when using the event-by-event, cascade-coarse-grained and event-fine-averaged spectra as input for the network, which are about 80%, 90% and 99%, respectively. A comparison with the prediction performance by deep neural network (DNN) with only the normalized pion transverse momentum spectra is also made. High-level features of pion spectra captured by a carefully-trained neural network were found to be able to distinguish the nature of the QCD transition even in a simulation scenario which is close to the experiments.

    Comments:
    16 pages, 21 figures. Updated version for the publication in Eur. Phys. J. C
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1910.11530 [pdf]
    EPJC(2020)·74 citations
  6. 06

    [Submitted on 25 Oct 2019] (cross-list from hep-ph)

    Hadron-in-jet production at partonic threshold

    Tom Kaufmann🇩🇪 · Xiaohui Liu🇨🇳 · Asmita Mukherjee🇮🇳 · Felix Ringer🇺🇸 · Werner Vogelsang🇩🇪

    We consider the longitudinal momentum distribution of hadrons inside jets in proton-proton collisions. At partonic threshold large double logarithmic corrections arise which need to be resummed to all orders. We develop a factorization formalism within SCET that allows for the joint resummation of threshold and jet radius logarithms. We achieve next-to-leading logarithmic NLL accuracy by including non-global logarithms in the leading-color approximation. Overall, we find that the threshold resummation leads to a sizable enhancement of the cross section and a reduced QCD scale dependence, suggesting that the all-order resummation can be important for the reliable extraction of fragmentation functions in global analyses when jet substructure data is included.

    Comments:
    22 pages, 4 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1910.11746 [pdf]
    JHEP(2020)·12 citations

Affiliations

first authorsco-authorsvia INSPIRE