121047854
Charmonium production and elliptic flow in relativistic heavy-ion collisions
Using the two-component model for charmonium production, which includes contributions from both initial hard nucleon-nucleon scattering and from regeneration in the quark-gluon plasma, we have studied the nuclear modification factor RAA and elliptic flow v2 of J= in relativistic heavy-ion collisions. For the expansion dynamics of produced hot dense matter, we have introduced a schematic fire-cylinder model with its transverse acceleration determined from the pressure gradient inside the fire-cylinder and azimuthally anisotropic expansion parameterized to reproduce measuredv2 of light hadrons. We have assumed that light hadrons freeze out at the temperature of 120 MeV while charmonia at 160 MeV, similar to the kinetic and chemical freeze-out temperatures in the statistical model, respectively. For the properties of charmonia in the quark-gluon plasma, we have used the screening mass between their charm and anticharm quarks and their dissociation cross sections given by the perturbative QCD (pQCD) in the leading order and up to the next-to-leading order, respectively. For the relaxation time of charm and anticharm quarks in the quark-gluon plasma, we have also used the one calculated in the leading order pQCD. Modeling the effect of higher-order corrections in pQCD by introducing multiplicative factors to the dissociation cross sections of charmonia and the elastic scattering cross sections of charm and anticharm quarks, we have found that this effect is small for the RAA of J= as they suppress the number of initially produced J= but enhance the number of regenerated ones. The higher-order corrections increase, however, the v2 of J= . Our results thus suggest that thev2 of J= can play an important role in discriminating between J= production from initial hard collisions and from regeneration in the quark-gluon plasma.
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.
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.
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.
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.
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.
119242109
Molecular clumps and star formation associated with the infrared dust bubble N131
Aims. The aim is to explore the interstellar medium around the dust bubble N131 and search for signatures of star formation. 
Methods. We perform a multiwavelength study around the N131 with data taken from large-scale surveys of infrared observation with online archive. We present new observations of three CO J = 1 - 0 isotope variants from Purple Mountain Observatory 13.7 m telescope. We analyze the distribution of the molecular gas and dust in the environment of the N131. We use color-color diagrams to search for young stellar objects and identify exciting star candidates. 
Results. The kinematic distance of about 8.6 kpc has been adopted as the distance of the bubble N131 from the Sun in this work. We have found a ring of clouds in CO emission coincident with the shell of N131 seen in the Spitzer telescope images, and two giant elongated molecular clouds of CO emission appearing on opposite sides of the ringlike shell of N131. There is a cavity within bubble at 1.4 GHz and 24 {\mu}m. Seven IRAS point sources are distributed along the ringlike shell of the bubble N131. 15 exciting stars and 63 YSOs candidates have been found. The clustered class I and II YSOs are distributed along the elongated clouds in the line of sight.
9281488
On Computing Upper Limits to Source Intensities
A common problem in astrophysics is determining how bright a source could be and still not be detected in an observation. Despite the simplicity with which the problem can be stated, the solution involves complicated statistical issues that require careful analysis. In contrast to the more familiar confidence bound, this concept has never been formally analyzed, leading to a great variety of often ad hoc solutions. Here we formulate and describe the problem in a self-consistent manner. Detection significance is usually defined by the acceptable proportion of false positives (background fluctuations that are claimed as detections, or Type I error), and we invoke the complementary concept of false negatives (real sources that go undetected, or Type II error), based on the statistical power of a test, to compute an upper limit to the detectable source intensity. To determine the minimum intensity that a source must have for it to be detected, we first define a detection threshold and then compute the probabilities of detecting sources of various intensities at the given threshold. The intensity that corresponds to the specified Type II error probability defines that minimum intensity and is identified as the upper limit. Thus, an upper limit is a characteristic of the detection procedure rather than the strength of any particular source. It should not be confused with confidence intervals or other estimates of source intensity. This is particularly important given the large number of catalogs that are being generated from increasingly sensitive surveys. We discuss, with examples, the differences between these upper limits and confidence bounds. Both measures are useful quantities that should be reported in order to extract the most science from catalogs, though they answer different statistical questions: an upper bound describes an inference range on the source intensity, while an upper limit calibrates the detection process. We provide a recipe for computing upper limits that applies to all detection algorithms.
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.
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.
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 .