119165305
INCOMPRESSIBILITY OF ASYMMETRIC NUCLEAR MATTER
Using an isospin- and momentum-dependent modified Gogny (MDI) interaction, the Skyrme-Hartree-Fock (SHF) approach, and a phenomenological modified Skyrme-like (MSL) model, we have studied the incompressibility Ksat(δ) of isospin asymmetric nuclear matter at its saturation density. Our results show that in the expansion of Ksat(δ) in powers of isospin asymmetry δ, i.e., Ksat(δ) = K0 + Ksat,2δ2 + Ksat,4δ4 + O(δ6), the magnitude of the 4th-order Ksat,4 parameter is generally small. The 2nd-order Ksat,2 parameter thus essentially characterizes the isospin dependence of the incompressibility of asymmetric nuclear matter at saturation density. Furthermore, the Ksat,2 can be expressed as in terms of the slope parameter L and the curvature parameter Ksym of the symmetry energy and the third-order derivative parameter J0 of the energy of symmetric nuclear matter at saturation density, and we find the higher order J0 contribution to Ksat,2 generally cannot be neglected. Also, we have found a linear correlation between Ksym and L as well as between J0/K0 and K0. Using these correlations together with the empirical constraints on K0 and L, the nuclear symmetry energy Esym(ρ0) at normal nuclear density, and the nucleon effective mass, we have obtained an estimated value of Ksat,2 = -370 ± 120 MeV for the 2nd-order parameter in the isospin asymmetry expansion of the incompressibility of asymmetric nuclear matter at its saturation density.
118536957
Locating the inner edge of the neutron star crust using terrestrial nuclear laboratory data
Within both dynamical and thermodynamical approaches using the equation of state for neutron-rich nuclear matter constrained by the recent isospin diffusion data from heavy-ion reactions in the same subsaturation density range as the neutron star crust, the density and pressure at the inner edge separating the liquid core from the solid crust of neutron stars are determined to be $0.040 {\mathrm{fm}}^{\ensuremath{-}3}\ensuremath{\leqslant}{\ensuremath{\rho}}_{t}\ensuremath{\leqslant}0.065 {\mathrm{fm}}^{\ensuremath{-}3}$ and 0.01 MeV/${\mathrm{fm}}^{3}\ensuremath{\leqslant}{P}_{t}\ensuremath{\leqslant}0.26$ MeV/${\mathrm{fm}}^{3}$, respectively. These together with the observed minimum crustal fraction of the total moment of inertia allow us to set a new limit for the radius of the Vela pulsar significantly different from the previous estimate. It is further shown that the widely used parabolic approximation to the equation of state of asymmetric nuclear matter leads systematically to significantly higher core-crust transition densities and pressures, especially with stiffer symmetry energy functionals.
119164414
Nuclear constraints on non-Newtonian gravity at femtometer scale
Effects of the non-Newtonian gravity on properties of finite nuclei are studied by consistently incorporating both the direct and exchange contribution of the Yukawa potential in the Hartree–Fock approach using a well-tested Skyrme force for the strong interaction. It is shown for the first time that the strength of the Yukawa term in the non-Newtonian gravity is limited to log (|α|) < 1.75/[λ(fm)]0.54 + 33.6 within the length scale of λ = 1 − 10 fm in order for the calculated properties of finite nuclei not to be in conflict with accurate experimental data available.
119184097
Imprints of Nuclear Symmetry Energy on Properties of Neutron Stars
Significant progress has been made in recent years in constraining the density dependence of nuclear symmetry energy using terrestrial nuclear laboratory data. Around and below the nuclear matter saturation density, the experimental constraints start to merge in a relatively narrow region. At supra-saturation densities, there are, however, still large uncertainties. After summarizing the latest experimental constraints on the density dependence of nuclear symmetry energy, we highlight a few recent studies examining imprints of nuclear symmetry energy on the binding energy, energy release during hadron-quark phase transitions as well as the ω-mode frequency and damping time of gravitational wave emission of neutron stars.
119288462
Non-Newtonian gravity in finite nuclei
In this talk, we report our recent study of constraining the non-Newtonian gravity at femtometer scale. We incorporate the Yukawa-type non-Newtonian gravitational potential consistently to the Skyrme functional form using the exact treatment for the direct contribution and density-matrix expansion method for the exchange contribution. The effects from the non-Newtonian potential on finite nuclei properties are then studied together with a well-tested Skyrme force. Assuming that the framework without non-Newtonian gravity can explain the binding energies and charge radii of medium to heavy nuclei within 2% error, we set an upper limit for the strength of the non-Newtonian gravitational potential at femtometer scale.
125427818
Anisotropic flows and dihadron correlations in heavy ion collisions
Using a multiphase transport model that includes both initial partonic and final hadronic scatterings, we have studied anisotropic flows and dihadron correla tions as functions of pseudorapidity and azimuthal angular differences between trigger and associated particles in heavy ion collisions at LHC. With parameters in the model determined from fitting t he measured multiplicity density of mid-pseudorapidity charged particles in central collis ions and their elliptic flow in mid-central collisions, the calculated higher-order anisotropic flows from the two-particle cumulant method reproduce approximately those measured in experiments. Similar to experimental results, the two-dimensional dihadron correlations at most central collisions show a ridge structure at the near side and a broad structure at the away side. The short- and long-range dihadron azimuthal correlations, corresponding to small and large pseudorapidity differences, respectively, are studied for triggering particles with different transverse mom enta and are found to be qualitatively consistent with experimental results.
119273779
Submillimeter/millimeter observations of the high-mass star forming region IRAS 22506+5944 ∗
The mapping observations of CO J = 2-1, CO J = 3-2, 13 CO J = 2-1 and 13 CO J = 3-2 lines in the direction of IRAS 22506+5944 have been made. The results show that the cores in the J = 2-1 transition lines have a similar morphology to those in the J = 3-2 transition lines. Bipolar molecular outflows are verified. The prior IRAS 22506+5944 observations indicated that two IRAS sources and three H 2 O masers were located close to the peak position of the core. One of the IRAS sources may be the driving source of the outflows. In addition, the H 2 O masers may occur in relatively warm environments. The parameters of the dense core and outflow, obtained by the LTE method, indicate that IRAS 22506+5944 is a high-mass star formation region.
96780035
Kinematics and chemistry of the hot core in G20.08–0.14N
We present Submillimeter Array observations of the massive star-forming region G20.08-0.14N at 335 and 345 GHz. With the SMA data, 41 molecular transitions were detected related to 11 molecular species and their isotopologues, including SO2, SO, C34S, NS, C17O, SiO, CH3OH, HC3N, H13CO+, HCOOCH3 and NH2CHO. In G20.08-0.14N, 10 transition lines of the detected 41 transition lines belong to SO2, which dominates the appearance of the submillimeter-wave spectrum. To obtain the spatial kinematic distribution of molecules in G20.08-0.14N, we chose the strongest and unblended lines for the channel maps. The channel maps of C34S an SiO, together with their position-velocity diagrams, present that there are two accretion flows in G20.08-0.14N. Additionally, SiO emission shows a collimated outflow at the NE-SW direction. The direction of the outflow is for the first time revealed. The rotational temperature and the column density of CH3OH are 105 K and 3.1*10^{17} cm^{-2}, respectively. Our results confirm that a hot core is associated with G20.08-0.14N. The hot core is heated by a protostar radiation at it center, not by the external excitation from shocks. The images of the spatial distribution of different species have shown that the different molecules are located at the different positions of the hot core. Through comparing the spatial distributions and abundances of the molecules, we discuss possible chemical processes for producing the complex sulfur-bearing, nitrogen-bearing and oxygen-bearing molecules in G20.08-0.14N.
119284289
The tricky azimuthal dependence of jet quenching at RHIC and LHC via CUJET2.0
Abstract High transverse momentum neutral pion and charged hadron suppression pattern with respect to reaction plane at RHIC and LHC energies in central and semi-peripheral AA collisions are studied in a perturbative QCD based model, CUJET2.0. CUJET2.0 has dynamical DGLV radiation kernel and Thoma–Gyulassy elastic energy loss, with both being generalized to including multi-scale running strong coupling as well as energy loss probability fluctuations, and the full jet path integration is performed in a low p T flow data constrained medium which has 2+1D viscous hydrodynamical expanding profile. We find that in CUJET2.0, with only one control parameter, α max , the maximum coupling strength, fixed to be 0.26, the computed nuclear modification factor R AA in central and semi-peripheral AA collisions are consistent with RHIC and LHC data at average χ 2 / d.o.f. 1.5 level. Simultaneous agreements with high p T azimuthal anisotropy v 2 data are acquired given average α max over in-plane and out-of-plane paths varying as little as 10%, suggesting a non-trivial dependence of the high p T single particle v 2 on the azimuthally varied strong coupling.
53135280
Azimuthal jet flavor tomography with CUJET2.0 of nuclear collisions at RHIC and LHC
A bstractA perturbative QCD based jet tomographic Monte Carlo model, CUJET2.0, is presented to predict jet quenching observables in relativistic heavy ion collisions at RHIC/BNL and LHC/CERN energies. This model generalizes the DGLV theory of flavor dependent radiative energy loss by including multi-scale running strong coupling effects. It generalizes CUJET1.0 by computing jet path integrations though more realistic 2 + 1D transverse and longitudinally expanding viscous hydrodynamical fields contrained by fits to low pT flow data. The CUJET2.0 output depends on three control parameters, (αmax, fE, fM ), corresponding to an assumed upper bound on the vacuum running coupling in the infrared and two chromo-electric and magnetic QGP screening mass scales (fEμ(T ), fMμ(T )) where μ(T ) is the 1-loop Debye mass. We compare numerical results as a function of αmax for pure and deformed HTL dynamically enhanced scattering cases corresponding to (fE = 1, 2, fM = 0) to data of the nuclear modification factor, RAAf(pT, ϕ; s,b$$ \sqrt{s}, b $$) for jet fragment flavors f = π, D, B, e at s$$ \sqrt{s} $$ = 0.2 − 2.76 ATeV c.m. energies per nucleon pair and with impact parameter b = 2.4, 7.5 fm. A χ2 analysis is presented and shows that RAAπ data from RHIC and LHC are consistent with CUJET2.0 at the χ2/d.o.f < 2 level for αmax = 0.23 − 0.30. The corresponding q^$$ \widehat{q} $$(Ejet, T )/T3 effective jet transport coefficient field of this model is computed to facilitate comparison to other jet tomographic models in the literature. The predicted elliptic asymmetry, v2(pT ; s$$ \sqrt{s} $$, b) is, however, found to significantly underestimated relative to RHIC and LHC data. We find the χv22$$ {\chi}_{v_2}^2 $$ analysis shows that v2 is very sensitive to allowing even as little as 10% variations of the path averaged αmax along in and out of reaction plane paths.
119215891
SUBMILLIMETER ARRAY AND VERY LARGE ARRAY OBSERVATIONS IN THE HYPERCOMPACT H II REGION G35.58-0.03
The formation of hypercompact (HC) H II regions is an important stage in massive star formation. Spectral line and continuum observations can explore its dynamic conditions. We present high angular resolution observations carried out with the Submillimeter Array (SMA) and the Very Large Array (VLA) toward the HC H II region G35.58-0.03. With the 1.3?mm SMA and 1.3?cm VLA, we detected a total of about 25 transitions of 8 different species and their isotopologues (CO, CH3CN, SO2, CH3CCH, OCS, CS, H, and NH3). G35.58-0.03 consists of an HC H II core with electron temperature ?K, emission measure EM 1.9 ? 109?pc?cm?6, local volume electron density ne = 3.3 ? 105?cm?3, and a same width of radio recombination line FWHM? 43.2?km s?1 for both H30? and H38? at its intrinsic core size ~3714 AU. The H30? line shows evidence of an ionized outflow driving a molecular outflow. Based on the derived Lyman continuum flux, there should be an early-type star equivalent to O6.5 located inside the H II region. From the continuum spectral energy distribution from 3.6?cm, 2.0?cm, 1.3?cm, 1.3?mm and 0.85?mm to 0.45?mm, we distinguished the free-free emission (25% ~ 55%) from the warm dust component (75%?~ 45%) at 1.3?mm. The molecular envelope shows evidence of infall and outflow with an infall rate of 0.05 M ? yr?1 and a mass loss rate of 5.2 ? 10?3 M ? yr?1. The derived momentum (~0.05 M ? km s?1) is consistent between the infalling and outflowing gas per year. It is suggested that the infall is predominant and the envelope mass of dense core is increasing rapidly, but the accretion in the inner part might already be halted.