Relativistic description of magnetic moments in nuclei with doubly closed shells plus or minus one nucleon

Using the relativistic point-coupling model with density functional PC-PK1, the magnetic moments of the nuclei $^{207}$Pb, $^{209}$Pb, $^{207}$Tl and $^{209}$Bi with a $jj$ closed-shell core $^{208}$Pb are studied on the basis of relativistic mean field (RMF) theory. The corresponding time-odd fields, the one-pion exchange currents, and the first- and second-order corrections are taken into account. The present relativistic results reproduce the data well. The relative deviation between theory and experiment for these four nuclei is 6.1% for the relativistic calculations and somewhat smaller than the value of 13.2% found in earlier non-relativistic investigations. It turns out that the $\pi$ meson is important for the description of magnetic moments, first by means of one-pion exchange currents and second by the residual interaction provided by the $\pi$ exchange.Comment: 11 pages, 7 figure

Constraints on models for the initial collision geometry in ultra relativistic heavy ion collisions

Monte Carlo (MC) simulations are used to compute the centrality dependence of the collision zone eccentricities ($\epsilon_{2,4}$), for both spherical and deformed ground state nuclei, for different model scenarios. Sizable model dependent differences are observed. They indicate that measurements of the $2^{\text{nd}}$ and $4^{\text{th}}$ order Fourier flow coefficients $v_{2,4}$, expressed as the ratio $\frac{v_4}{(v_2)^2}$, can provide robust constraints for distinguishing between different theoretical models for the initial-state eccentricity. Such constraints could remove one of the largest impediments to a more precise determination of the specific viscosity from precision $v_{2,4}$ measurements at the Relativistic Heavy Ion Collider (RHIC).Comment: 4 pages, 3 figs - version accepted for publicatio

Energy loss for heavy quarks in relation to light partons; is radiative energy loss for heavy quarks anomalous?

The scaling properties of jet suppression measurements are compared for non-photonic electrons ($e^{\pm}$) and neutral pions ($\pi^0$) in Au + Au collisions at $\sqrt{s_{NN}}=200$ GeV. For a broad range of transverse momenta and collision centralities, the comparison is consistent with jet quenching dominated by radiative energy loss for both heavy and light partons. Less quenching is indicated for heavy quarks via $e^{\pm}$; this gives an independent estimate of the transport coefficient $\hat{q}$ that agrees with its magnitude obtained from quenching of light partons via $\pi^0$'s.Comment: Published versio

Properties of Zr hypernuclei in deformed Skyrme Hartree-Fock approach

National Natural Science Foundation of China [10605018]; New Century Excellent Talents in University [NCET-07-0730]Properties of the even-N Zr isotopes and their corresponding single-Lambda and double-Lambda hypernuclei are studied in the deformed Skyrme-Hartree-Fock approach. Binding energy, the two-neutron separation energies, radii are studied from beta-stable zone to the neutron drip line in this paper. The neutron drip line nuclei predicted with SLy4 and SkI4 interactions are (122)Zr and (138)Zr, respectively. The neutron drip line of single-Lambda and double-Lambda hypernuclei are (139)(Lambda)Zr and (142)(2 Lambda)Zr with SkI4 interaction, respectively. The predicted hyperon drip line hypernuclei with (80)Zr and (138)Zr cores ads (100)(20 Lambda)Zr and (188)(50 Lambda)Zr, respectively

Rethinking blockchains in the Internet of Things era from a wireless communication perspective

Due to the rapid development of the internet of Things (ioT), a massive number of devices are connected to the internet. For these distributed devices in ioT networks, how to ensure their security and privacy becomes a significant challenge. Blockchain technology provides a promising solution to protect the data integrity, provenance, privacy, and consistency for ioT networks. in blockchains, communication is a prerequisite for participants, which are distributed in the system, to reach consensus. However, in ioT networks, most of the devices communicate through wireless links, which are not always reliable. Hence, the communication reliability of ioT devices influences the system security. in this article, we rethink the roles of communication and computing in blockchains by accounting for communication reliability. We analyze the trade-off between communication reliability and computing power in blockchain security, and present a lower bound to the computing power that is needed to conduct an attack with a given communication reliability. Simulation results show that adversarial nodes can succeed in tampering with a block with less computing power by hindering the propagation of blocks from other nodes