Nuclear Theory·nucl-th

Thursday·November 16, 2017

9 papers—3 primary·6 cross-listed

01
The equilibrium and dynamical cumulants of QCD chiral order parameter with parametric Landau free energy
Lijia Jiang🇨🇳 · Horst Stoecker🇩🇪 · Jun-Hui Zheng🇨🇳
By linearly parameterizing the QCD Landau free energy near the critical point in the baryon chemical potential and temperature plane, we study the fluctuations of the QCD chiral order parameter field (the $σ$ field) in the equilibrium case and dynamical phase transition, respectively. By setting the system size to the typical size of the QGP fireball ( $\approx 1 0^{3}$ fm $^{3}$ ), we show that in the equilibrium case, the discontinuity of the order parameter in the first order phase transition region is replaced by smooth crossover, and the corresponding fluctuations are broadened. Meanwhile, the quartic cumulant $κ_{4}$ of the $σ$ field is generally negative near the phase transition line. We further derive the dynamical evolution of the QCD Landau free energy in the Fokker-Plank framework, based on which we deduce the dynamical cumulants of the $σ$ field. Assuming the temperature decreases as a known function of time, we numerically evaluate the dynamical cumulants and confirm that the cumulants present clear memory effects. Moreover, the memory effects on the first order phase transition side is stronger than that on the crossover side, and the dynamical cumulants at the hypothetical freeze-out line present rich non-monotonic structures.
nucl-thhep-phEPJC(2023)·8 citations
02
Perturbative accelerating solutions of relativistic hydrodynamics
Balint Kurgyis🇭🇺 · Mate Csanad🇭🇺
In ultra-relativistic collisions of heavy ions, the strongly interacting Quark Gluon Plasma (sQGP) is created. The fluid nature of the sQGP was one of the important discoveries of high energy heavy ion physics in the last decades. Henceforth the explosion of this matter may be described by hydrodynamical models. Besides numerical simulations, it is important to study the analytic solutions of the equations of hydrodynamics, as these enable us to understand the connection of the final and initial states better. In this paper we present a perturbative, accelerating solution of relativistic hydrodynamics, on top of a known class of solutions describing Hubble-expansion. We describe the properties of this class of perturbative solutions, and investigate a few selected solutions in detail.
nucl-thUniverse(2017)·3 citations
03
Light cluster production at NICA
N.-U. Bastian🇵🇱 · D. Blaschke🇵🇱 · G. Röpke🇷🇺
In a recent publication the importance of measuaring light clusters at future NICA and FAIR experiments as "rare probes" for in-medium characteristics was presented. Within theoretical conciderations is shown how clusters would be affected by medium affects as given collider energies.
nucl-thActa Phys.Polon.Supp.(2017)·1 citation
04
The Magnetic Field Distribution in Strongly Magnetized Neutron Stars
V. Dexheimer🇺🇸 · B. Franzon🇩🇪 · R. O. Gomes🇩🇪 · R. L. S. Farias🇧🇷 · S. S. Avancini🇧🇷 · S. Schramm🇩🇪
In this work, we expand on a previously reported realistic calculation of the magnetic field profile for the equation of state inside strongly magnetized neutron stars. In addition to showing that magnetic fields increase quadratically with increasing baryon chemical potential of magnetized matter (instead of exponentially, as previously assumed), we show here that the magnetic field increase with baryon number density is more complex and harder to model. We do so by the analysis of several different realistic models for the microscopic description of matter in the star (including hadronic, hybrid and quark models) combined with general relativistic solutions by solving Einstein-Maxwell's field equations in a self-consistent way for stars endowed with a poloidal magnetic field.
↳ astro-ph.HEastro-ph.SRnucl-thAstron.Nachr.(2017)·11 citations
05
Constraints on interquark interaction parameters with GW170817 in a binary strange star scenario
Enping Zhou🇨🇳 · Xia Zhou🇨🇳 · Ang Li🇨🇳
The LIGO/VIRGO detection of the gravitational waves from a binary merger system, GW170817, has put a clean and strong constraint on the tidal deformability of the merging objects. From this constraint, deep insights can be obtained in compact star equation of states, which has been one of the most puzzling problems for nuclear physicists and astrophysicists. Employing one of the most widely-used quark star EOS model, we characterize the star properties by the strange quark mass ( $m_{s}$ ), an effective bag constant ( $B_{eff}$ ), the perturbative QCD correction ( $a_{4}$ ), as well as the gap parameter ( $Δ$ ) when considering quark pairing, and investigate the dependences of the tidal deformablity on them. We find that the tidal deformability is dominated by $B_{eff}$ , and insensitive to $m_{s}$ , $a_{4}$ . We discuss the correlation between the tidal deformability and the maximum mass ( $M_{TOV}$ ) of a static quark star, which allows the model possibility to rule out the existence of quark stars with future gravitational wave observations and mass measurements. The current tidal deformability measurement implies $M_{TOV} \leq 2.18 M_{⊙}$ ( $2.32 M_{⊙}$ when pairing is considered) for quark stars. Combining with two-solar-mass pulsar observations, we also make constraints on the poorly known gap parameter $Δ$ for color-flavor-locked quark matter.
↳ astro-ph.HEastro-ph.SRgr-qcnucl-thPRD(2018)·168 citations
06
Exclusive neutrino-production of a charmed vector meson and transversity gluon GPDs
B. Pire🇫🇷 · L. Szymanowski🇵🇱
We calculate at the leading order in $α_{s}$ the QCD amplitude for exclusive neutrino production of a $D^{*}$ or $D_{s}^{*}$ charmed vector meson on a nucleon. We work in the framework of the collinear QCD approach where generalized parton distributions (GPDs) factorize from perturbatively calculable coefficient functions. We include $O (m_{c})$ terms in the coefficient functions and $O (m_{D})$ term in the definition of heavy meson distribution amplitudes. The show that the analysis of the angular distribution of the decay $D_{(s)}^{*} \to D_{(s)} π$ allows to access the transversity gluon GPDs.
↳ hep-phhep-exnucl-exnucl-thPRD(2017)·21 citations
07
Structure of the Nucleon and its Excitations
Waseem Kamleh🇦🇺 · Derek Leinweber🇦🇺 · Zhan-wei Liu🇦🇺 · Finn Stokes🇦🇺 · Anthony Thomas🇦🇺 · Samuel Thomas🇦🇺 · Jia-jun Wu🇦🇺
The structure of the ground state nucleon and its finite-volume excitations are examined from three different perspectives. Using new techniques to extract the relativistic components of the nucleon wave function, the node structure of both the upper and lower components of the nucleon wave function are illustrated. A non-trivial role for gluonic components is manifest. In the second approach, the parity-expanded variational analysis (PEVA) technique is utilised to isolate states at finite momenta, enabling a novel examination of the electric and magnetic form factors of nucleon excitations. Here the magnetic form factors of low-lying odd-parity nucleons are particularly interesting. Finally, the structure of the nucleon spectrum is examined in a Hamiltonian effective field theory analysis incorporating recent lattice-QCD determinations of low-lying two-particle scattering-state energies in the finite volume. The Roper resonance of Nature is observed to originate from multi-particle coupled-channel interactions while the first radial excitation of the nucleon sits much higher at approximately 1.9 GeV.
↳ hep-lathep-phnucl-thEPJ Web Conf.(2018)·5 citations
08
Anisotropy of thermal dileptons
V.V. Goloviznin🇷🇺 · A.M. Snigirev🇷🇺 · G.M. Zinovjev🇺🇦
The meaningful specific anisotropy in the angle distribution of leptons with respect to the three-momentum of pair is predicted as a feasibility signature of synchrotron-like mechanism resulting from the quarks interacting with a collective confining color field in the heavy ion collisions. The lepton pair production rate and the spectrum of pair invariant mass are presented for this new dilepton source that is apparently not taken into consideration in the available phenomenological estimates.
↳ hep-phnucl-exnucl-th1 citation
09
Net-baryon number fluctuations in the Hybrid Quark-Meson-Nucleon model at finite density
Michał Marczenko🇵🇱 · Chihiro Sasaki🇵🇱
We study the mean-field thermodynamics and the characteristics of the net-baryon number fluctuations at the phase boundaries for the chiral and deconfinement transitions in the Hybrid Quark-Meson-Nucleon model. The chiral dynamics is described in the linear sigma model, whereas the quark confinement is manipulated by a medium-dependent modification of the particle distribution functions, where an additional scalar field is introduced. At low temperature and finite baryon density, the model predicts a first-, second-order chiral phase transition, or a crossover, depending on the expectation value of the scalar field, and a first-order deconfinement phase transition. We focus on the influence of the confinement over higher-order cumulants of the net-baryon number density. We find that whereas the cumulants show a substantial enhancement around the chiral phase transition, they are not as sensitive to the deconfinement transition.
↳ hep-phnucl-thPRD(2018)·38 citations

Affiliations

first authorsco-authorsvia INSPIRE