44780624
Partonic Effects on Higher-Order Anisotropic Flows in Relativistic Heavy-Ion Collisions
Higher-order anisotropic flows ${v}_{4}$ and ${v}_{6}$ of charged hadrons in heavy-ion collisions at the Relativistic Heavy Ion Collider are studied in a multiphase transport model that has previously been used successfully for describing the elliptic flow ${v}_{2}$ of identified hadrons in these collisions. We find that the same parton scattering cross section of about $10\phantom{\rule{0.3em}{0ex}}\text{mb}$ used in explaining the measured ${v}_{2}$ of charged hadrons can also reproduce the recent data on their ${v}_{4}$ and ${v}_{6}$ from $\text{Au}+\text{Au}$ collisions at $\sqrt{s}=200A\phantom{\rule{0.3em}{0ex}}\text{GeV}$. It is further found that ${v}_{4}$ is a more sensitive probe of the initial partonic dynamics in these collisions than ${v}_{2}$. Moreover, higher-order parton anisotropic flows are non-negligible and satisfy the scaling relation ${v}_{n,q}({p}_{T})\ensuremath{\sim}{v}_{2,q}^{n∕2}({p}_{T})$, which leads naturally to the observed similar scaling relation among hadron anisotropic flows when the coalescence model is used to describe hadron production from the partonic matter.
118388447
Correlations between the nuclear breathing mode energy and properties of asymmetric nuclear matter
Based on microscopic Hartree–Fock + random phase approximation calculations with Skyrme interactions, we study the correlations between the nuclear breathing mode energy EISGMR and properties of asymmetric nuclear matter with a recently developed analysis method. Our results indicate that the EISGMR of 208Pb exhibits moderate correlations with the density slope L of the symmetry energy and the isoscalar nucleon effective mass m*s, 0 besides a strong dependence on the incompressibility K0 of symmetric nuclear matter. Using the present empirical values of L = 60 ± 30 MeV and m*s, 0 = (0.8 ± 0.1)m, we obtain a theoretical uncertainty of about ±16 MeV for the extraction of K0 from the EISGMR of 208Pb. Furthermore, we find that the EISGMR difference between 100Sn and 132Sn strongly correlates with L and thus provides a potentially useful probe of the symmetry energy.
4046382
Nuclear symmetry potential in the relativistic impulse approximation
Using the relativistic impulse approximation with the Love-Franey NN scattering amplitude developed by Murdock and Horowitz, we investigate the low-energy (100{<=}E{sub kin}{<=}400 MeV) behavior of the nucleon Dirac optical potential, the Schroedinger-equivalent potential, and the nuclear symmetry potential in isospin asymmetric nuclear matter. We find that the nuclear symmetry potential at fixed baryon density decreases with increasing nucleon energy. In particular, the nuclear symmetry potential at saturation density changes from positive to negative values at nucleon kinetic energy of about 200 MeV. Furthermore, the obtained energy and density dependence of the nuclear symmetry potential is consistent with those of the isospin- and momentum-dependent MDI interaction with x=0, which has been found to describe reasonably well both the isospin diffusion data from heavy-ion collisions and the empirical neutron-skin thickness of {sup 208}Pb.
17798154
Supersoft symmetry energy encountering non-Newtonian gravity in neutron stars.
Considering the non-Newtonian gravity proposed in grand unification theories, we show that the stability and observed global properties of neutron stars cannot rule out the supersoft nuclear symmetry energies at suprasaturation densities. The degree of possible violation of the inverse-square law of gravity in neutron stars is estimated using an equation of state of neutron-rich nuclear matter consistent with the available terrestrial laboratory data.
120983580
Isospin dependent Pauli blocking and nucleon mean free path in isospin-asymmetric nuclear matter
210000982
Probing the equation of state of neutron-rich matter with intermediate energy heavy-ion collisions
Nuclear reactions induced by stable and/or radioactive neutronrich nuclei provide the opportunity to pin down the equation of state of neutron-rich matter, especially the density (ρ) dependence of its isospin-dependent part, i.e., the nuclear symmetry energy Esym. A conservative constraint, 32(ρ/ρ0) 0.7 < Esym(ρ) < 32(ρ/ρ0) , around the nuclear matter saturation density ρ0 has recently been obtained from the isospin diffusion data in intermediate energy heavy-ion collisions. We review this exciting result and discuss its consequences and implications on nuclear effective interactions, radii and cooling mechanisms of neutron stars.
119110745
Causal loops in the theory of relative locality
We find that relative locality, a recently proposed Planck-scale deformation of special relativity, suffers from the existence of causal loops. A simple and general construction of such on-shell loop processes is studied. We then show that even in one of the weakest deformations of the Poincar\'e group in relative locality, causality can be violated.
119238467
Orientability of loop processes in relative locality
Inspired by recent results of unusual properties of loop processes in relative locality, we introduce a way to classify loops in the case of kappa-Poincare momentum space. We show that the notion of orientability is deeply connected to a few essential properties of loop processes. Nonorientable loops have "effective curvature", which explicitly breaks translation symmetry, and can lead to a breaking of causality and global momentum conservation. Orientable loops, on the other hand, are "flat." Causality and global momentum conservation are all well preserved in this kind of loops. We comment that the nontrivial classical loops in relative locality might be understood as dual effects from general relativity, and some physical implications are discussed.
137374294
Preliminary Lattice Design of the SSRF Storage Ring
122248926
Simulation study of beam-beam effects
The Beijing Electron-Positron Collider (BEPC) will be upgraded to BEPCII, and the luminosity will be about 100 times higher. We developed a three-dimensional strong-strong PIC code to study the beam-beam effects in BEPCII. The transportation through the arc is the same as that in Hirata's weak-strong code. The beam-beam force is computed directly by solving the Poisson equation using the Fourier analysis and cyclic reduction method, and the boundary potential is computed by circular convolution. The finite bunch length effect is included by longitudinal slices. An interpolation scheme is used to reduce the required slice number in simulations. The standard message passing interface is used to parallelize the code. The computing time increases linearly with (n+1), where n is the slice number. The calculated luminosity of BEPCII at the design working point is similar to 50% of the design value. The best area in the tune space is near (0.505,0.57) according to the survey, where the luminosity is similar to 80% of the design.