Beam energy dependence of Hanbury-Brown-Twiss radii from a blast-wave model

The beam energy dependence of correlation lengths (the Hanbury-Brown-Twiss radii) is calculated by using a blast-wave model and the results are comparable with those from RHIC-STAR beam energy scan data as well as the LHC-ALICE measurements. A set of parameter for the blast-wave model as a function of beam energy under study are obtained by fit to the HBT radii at each energy point. The transverse momentum dependence of HBT radii is presented with the extracted parameters for Au + Au collision at $\sqrt{s_{NN}} =$ 200 GeV and for Pb+Pb collisions at 2.76 TeV. From our study one can learn that particle emission duration can not be ignored while calculating the HBT radii with the same parameters. And tuning kinetic freeze-out temperature in a range will result in system lifetime changing in the reverse direction as it is found in RHIC-STAR experiment measurements.Comment: 9 pages, 9 figure

Retraction of articles by H. Zhong et al.

Retraction of 41 articles by H. Zhong et al.

Very Old Isolated Compact Objects as Dark Matter Probes

Very old isolated neutron stars and white dwarfs have been suggested to be probes of dark matter. To play such a role, two requests should be fulfilled, i.e., the annihilation luminosity of the captured dark matter particles is above the thermal emission of the cooling compact objects (request-I) and also dominate over the energy output due to the accretion of normal matter onto the compact objects (request-II). Request-I calls for very dense dark matter medium and the critical density sensitively depends on the residual surface temperature of the very old compact objects. The accretion of interstellar/intracluster medium onto the compact objects is governed by the physical properties of the medium and by the magnetization and rotation of the stars and may outshine the signal of dark matter annihilation. Only in a few specific scenarios both requests are satisfied and the compact objects are dark matter burners. The observational challenges are discussed and a possible way to identify the dark matter burners is outlined.Comment: 9 pages including 1 Figure, to appear in Phys. Rev.

Dichlorido(2,9-dimethyl-1,10-phenanthroline-κ2 N,N′)copper(II)

In the title compound, [CuCl2(C14H12N2)], the complex molecule has m symmetry, with the mirror plane oriented parallel to the planar molecule and the ligated CuII atom. The metal centre has a distorted tetra­hedral coordination formed by two N atoms from one 2,9-dimethyl-1,10-phenanthroline ligand and two Cl atoms. There is inter­molecular π–π stacking between adjacent 2,9-dimethyl-1,10-phenanthroline ligands, with a centroid–centroid distance of 3.733 (2)Å