118771568
Energy release from hadron-quark phase transition in neutron stars and the axial w mode of gravitational waves
Describing the hyperonic and quark phases of neutron stars with an isospin- and momentum-dependent effective interaction for the baryon octet and the MIT bag model, respectively, and using the Gibbs conditions to construct the mixed phase, we study the energy release from a neutron star owing to the hadron-quark phase transition. Moreover, the frequency and damping time of the first axial w mode of gravitational waves are studied for both hyperonic and hybrid stars. We find that the energy release is much more sensitive to the bag constant than the density dependence of the nuclear symmetry energy. Also, the frequency of the w mode is found to be significantly different with or without the hadron-quark phase transition and depends strongly on the value of the bag constant. Effects of the density dependence of the nuclear symmetry energy become, however, important for large values of the bag constant that lead to higher hadron-quark transition densities.
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.
119023494
Shear viscosity of nuclear matter
In this talk I report my recent study on the shear viscosity of neutron-rich nuclear matter from a relaxation time approach. An isospinand momentum-dependent interaction is used in the study. Effects of density, temperature, and isospin asymmetry of nuclear matter on its shear viscosity have been discussed. Similar to the symmetry energy, the symmetry shear viscosity is defined and its density and temperature dependence are studied.
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.
119269296
Outflow and accretion detections in the young stellar object IRAS 04579+4703
We present Submillimeter Array observations of the young stellar object IRAS 04579+4703 in the 1.3 mm continuum and in the 12 CO(2−1), 13 CO(2−1), and C 18 O(2−1) lines. The 1.3 mm continuum image reveals a flattened structure with a mass of 13 M � . The 12 CO(2−1) line map and position-velocity diagram, together with the broad wing (full width = 30 km s −1 )o f the 12 CO(2−1) line, clearly show that there is an outflow motion, which originates from an embedded massive YSO in this region. The lengths of the blue-shifted and red-shifted lobes are 0.14 pc and 0.13 pc, respectively. The total gas mass, average dynamical timescale, and
119110703
12CO J=2?1 and 12CO J=3?2 observations toward the high-mass protostellar candidate IRAS 20188+3928
We have carried out observations of 12 CO J =2–1 and 12 CO J =3–2 toward the high-mass protostellar candidate IRAS 20188+3928. Compared with previous observations, the 12 CO J =2–1 and 12 CO J =3–2 lines both have asymmetric profiles with an absorption dip. The velocity of the absorption dip is ~ 1.0 km s −1 . The spectral shape may be caused by rotation. The velocity-integrated intensity map and position-velocity diagram of the 12 CO J =2–1 line present an obvious bipolar component, further verifying that this region has an outflow motion. This region is also associated with an HII region, an IRAS source, and an H 2 O maser. The H 2 O maser has the velocity of 1.1 km s −1 . Compared with the components of the outflow, we find that the H 2 O maser is not associated with the outflow. Using the large velocity gradient model, we concluded that possible averaged gas densities of the blueshifted lobe and redshifted lobe are 1.0×10 5 cm −3 and 2.0×10 4 cm −3 , while kinetic temperatures are 26.9 K and 52.9 K, respectively. Additionally, the outflow has a higher integrated intensity ratio ( I CO J =3−2 / I CO J =2−1 ).
121568193
Energy determination at BEPC-II
The BEPC-II collider beam energy calibration system is discussed. The system is based on the Compton backscattering method. The expected precision of the electron and positron beam energy e determination is δ e / e ≈ 3 ⋅ 10 − 5 .
124654178
Extracting the jet transport coefficient from jet quenching in high-energy heavy-ion collisions
Within five different approaches to parton propagation and energy loss in dense matter, a phenomenological study of experimental data on suppression of large $p_T$ single inclusive hadrons in heavy-ion collisions at both RHIC and LHC was carried out. The evolution of bulk medium used in the study for parton propagation was given by 2+1D or 3+1D hydrodynamic models which are also constrained by experimental data on bulk hadron spectra. Values for the jet transport parameter $\hat q$ at the center of the most central heavy-ion collisions are extracted or calculated within each model, with parameters for the medium properties that are constrained by experimental data on the hadron suppression factor $R_{AA}$. For a quark with initial energy of 10 GeV we find that $\hat q\approx 1.2 \pm 0.3$ GeV$^2$/fm at an initial time $\tau_0=0.6$ fm/$c$ in Au+Au collisions at $\sqrt{s}=200$ GeV/n and $\hat q\approx 1.9 \pm 0.7 $ GeV$^2$/fm in Pb+Pb collisions at $\sqrt{s}=2.76 $ TeV/n. Compared to earlier studies, these represent significant convergence on values of the extracted jet transport parameter, reflecting recent advances in theory and the availability of new experiment data from the LHC.
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.