Production of the X(4014)as the Spin-2 Partner of X(3872)in e^(+)e^(-)Collisions

In 2021,the Belle collaboration reported the first observation of a new structure in theψ(2S)γfinal state produced in the two-photon fusion process.In the hadronic molecule picture,this new structure can be associatedwith the shallow isoscalar D*D* bound state and as such is an excellent candidate for the spin-2 partner of the X(3872)with the quantum numbers J^(PC)=2^(++)conventionally named X_(2).

Precision Tests of the Nonlinear Mode Coupling of Anisotropic Flow via High-Energy Collisions of Isobars

Valuable information on dynamics of expanding fluids can be inferred from the response of such systems to perturbations in their initial geometry.We apply this technique in high-energy^(96)Ru+^(96)Ru and^(96)Zr+^(96)Zr collisions to scrutinize the expansion dynamics of the quark-gluon plasma,where the initial geometry perturbations are sourced by the differences in deformations and radial profiles between^(96)Ru and^(96)Zr,and the collective response is captured by the change in anisotropic flow Vn between the two collision systems.Using a transport model,we analyze how the nonlinear coupling between lower-order flow harmonics V_(2)and V_(3)to the higher-order flow harmonics V_(4)and V_(5),expected to scale as V_(4)NL= χ_(4)V_(2)2and V_(5)NL= χ_(5)V_(2)V_(3),gets modified as one moves from^(96)Ru+^(96)Ru to^(96)Zr+^(96)Zr systems.We find that these scaling relations are valid to high precision:variations of order 20% in V_(4)NLand V_(5)NLdue to differences in quadrupole deformation,octupole deformation,and nuclear skin modify χ_(4)and χ_(5)by about 1–2%.Percent-level deviations are however larger than the expected experimental uncertainties and could be measured.Therefore,collisions of isobars with different nuclear structures are a unique tool to isolate subtle nonlinear effects in the expansion of the quark-gluon plasma that would be otherwise impossible to access in a single collision system.

血管造影及经皮经腔血管成形术(PTA)的工作人员射线照射量

从事诊断工作的人员职业性射线照射必须引起我们注意,以便采取一切必要的防护措施。若采取相应的预防措施,照射就不会超过临界剂量。

Raman spectroscopy of isolated carbyne chains confined in carbon nanotubes:Progress and prospects

Carbyne is an infinitely long linear chain of carbon atoms with sp1hybridization and the truly one-dimensional allotrope of carbon.While obtaining freestanding carbyne is still an open challenge,the study of confined carbyne,linear chains of carbon encapsulated in carbon nanotubes,provides a pathway to explore carbyne and its remarkable properties in a well-defined environment.In this review,we discuss the basics and recent advances in studying single confined carbyne chains by Raman spectroscopy,which is their primary spectroscopic characterization method.We highlight where single carbyne chain studies are needed to advance our understanding of confined carbyne as a material system and provide an overview of the open questions that need to be addressed and of those aspects currently under debate.

Ⅳ-Ⅵ族化合物量子阱和超晶格结构的物理及应用(英文)

In this review the electronic properties of cubic IV-VI compound hetero-, quantum well-, and superlattice structures are summarized. The host materials have a direct narrow gap at the L-points of the Brillouin-zone. In pseudobinary alloys (PbSnTe, PbSnSe) the gap decreases to zero and becomes inverted with higher Sn-concentrations, which offers the fasci-

Pressure and Spectral Density of Fermions at Finite Temperature

The pressure of a fermion system is expressed as a mass integral over the full two-point spectral densities within the real time formalism by use of the Keldysh representation for the propagators.This simpliSes the calculation significantly and allows a Dyson resummation.The expression is used to demonstrate that potential infrared divergences are rendered harmless.We apply it to check the pressures of an ideal fermion gas and of a chemically non-equilibrated quantum chromodynamics plasma.

New continuum and polarization observations of the Cygnus Loop with FAST I.Data processing and verification

We report on the continuum and polarization observations of the Cygnus Loop supernova remnant(SNR)conducted by the Five-hundred-meter Aperture Spherical radio Telescope(FAST).FAST observations provide high angular resolution and high sensitivity images of the SNR,which will help to disentangle its nature.We obtained Stokes I,Q and U maps over the frequency range of 1.03-1.46 GHz split into channels of 7.63 kHz.The original angular resolution is in the range of~3’-~3.’8,and we combined all the data at a common resolution of 4’.The temperature scale of the total intensity and the spectral index from the in-band temperature-temperature plot are consistent with previous observations,which validates the data calibration and map-making procedures.The rms sensitivity for the band-averaged total-intensity map is about 20 mK in brightness temperature,which is at the level of confusion limit.For the first time,we apply rotation measure(RM)synthesis to the Cygnus Loop to obtain the polarization intensity and RM maps.The rms sensitivity for polarization is about 5 mK,far below the total-intensity confusion limit.We also obtained RMs of eight extragalactic sources,and demonstrate that the wide-band frequency coverage helps to overcome the ambiguity of RM determinations.

Bistability in Coupled Oscillators Exhibiting Synchronized Dynamics

我们报导与二的同步行为联系的一些新结果联合了未击中振荡器(DDO ) 的双井。为经由线性州的错误反馈控制的驱动器和反应 DDO 的全球混乱同步的一些足够的代数学的标准借助于 Lyapunov 稳定性理论被获得。同步通过一个周期的引起注意的人与一个混乱引起注意的人在共存的一个双稳态的状态被完成。用线性不安分析，在参数空间和联系分叉的引起注意的人的流行被检验。Subcritical 和 supercritical Hopf 分叉和锁现象的模式的签名被发现的许多阿诺德舌头。

Growth-induced Stacking Faults of ZnO Nanorods Probed by Spatial Resolved Cathodoluminescence

Low density ZnO nanorods are grown by modified chemical vapor deposition on silicon substrates using gold as a catalyst.We use high resolution photoiuminescence spectroscopy to gain the optical properties of these nanorods in large scale.The as-grown samples show sharp near-band-gap luminescence with a full width at half maximum of bound exciton peaks at about 300μeV,and the ratio of ultraviolet/yellow luminescence larger than 100.Highly spatial and spectral resolved scanning electron microscope-cathodoluminescence is performed to excite the ZnO nanorods in single rods or different positions of single rods with the vapour-solid grovth mechanism.The bottom of the nanorod has a 3.31-eV luminescence,which indicates that basal plane stacking faults are related to the defects that are created at the first stage of growth due to the misfit between ZnO and Si.

Dust-Acoustic Waves in Strongly Coupled Dusty Plasmas Containing Variable-Charge Impurities

A relatively self-consistent theory of dust-acoustic waves in the strongly coupled dusty plasmas containing variable-charge impurities is given.Relevant physical processes such as dust elastic relaxation and dust charge relaxation are taken into account.It is shown that the negative dispersion of dust-acoustic waves due to the strong correlation of dusts is enhanced in the presence of dust-neutral collisions.

Electron-Helium Scattering in a Bichromatic Laser Field in the Second-Order Born Approximation

The elastic scattering of electrons in atomic helium assisted by a bichromatic laser field is investigated in the second order Born approximation. The target atom is approximated by a simple screening potential. The dependence of the differential cross section on the relative phase between the two laser components is calculated, and compared with the recent results of first order Born approximation [Sun J F, Liang M C and Zhu Z L 2007 Chin. Phys. Lett. 24 2572].

A Note on Similarity Reductions of Barotropic and Quasi-geostrophic Potential Vorticity Equation

没有在一条 β-plane 隧道上强迫和驱散，把古典谎言对称途径用于 barotropic 和伪因地球自转而引起的潜在的涡度方程，我们发现新对称，它没在一个以前的工作被介绍[F. 黄， Commun。Theor。Phys。(中国北京) 42 (2004 ) 903 ] 。一个一般有限转变组基于完整的谎言点对称被获得。而且，类似减小答案的二种新类型被获得。

Relativistic Chiral Description of the 1S0 Nucleon-Nucleon Scattering

Recently,a relativistic chiral nucleon-nucleon interaction was formulated up to leading order,which provides a good description of the phase shifts of J≤1 partial waves[Chin.Phys.C 42(2018)014103].Nevertheless,a separable regulator function that is not manifestly covariant was used in solving the relativistic scattering equation.In the present work,we first explore a covariant and separable form factor to regularize the kernel potential and then apply it to study the simplest but most challenging ^(1)S_(0) channel which features several lowenergy scales.In addition to being self-consistent,we show that the resulting relativistic potential can describe quite well the unique features of the ^(1)S_(0) channel at leading order,in particular the pole position of the virtual bound state and the zero amplitude at the scattering momentum ~340 MeV,indicating that the relativistic formulation may be more natural from the viewpoint of effective field theories.

IN SITU TEM OBSERVATION OF AMORPHOUS Nd_(x)Fe_(1-x)THIN FILMS AND THEIR CRYSTALLIZATION

The room temperature stability and crystallization of amorphous Nd_xFe_(1-x)thin films with x=0.06—0.90,prepared by flash evaporation at 77 K,were investigated by X-ray diffraction and TEM observation.The amorphous Nd_xFe_(1-x)films are stable at room temperature when 0.19<x<0.50.Crystallized phases grow along the surface of film as very thin flakes and become thick only at relatively high temperatures.After complete crystallization,the Nd_xFe_(1-x)films with x<0.50 are composed of Nd_2Fe-(17)and metal Nd,but no NdFe2,a phase expected to occur by phase diagram.

Nuclear Hexadecapole Deformation Effects on the Production of Super-Heavy Elements

We investigate the effects of the nuclear hexadecapole deformations on the interaction potentials between nuclei, the driving potentials and the fusion probabilities for some cold fusion reactions leading to super-heavy elements. It is found that nuclear hexadecapole deformations change significantly the structure of the driving potentials and the fusion probabilities for some reaction channels.

Analysis of the Low-Energy π^±p Elastic-Scattering Data

We report the results of a phase-shift analysis (PSA) of the low-energy π±p elastic-scattering data. Following the method which we had set forth in our previous PSA [1], we first investigate the self-consistency of the low-energy π±p elastic-scattering databases, via two separate analyses of (first) the π+p and (subsequently) the π-p elastic-scattering data. There are two main differences to our previous PSA: 1) we now perform only one test for the acceptance of each data set (based on its contribution to the overall 2) and 2) we adopt a more stringent acceptance criterion in the statistical tests. We show that it is possible to obtain self-consistent databases after removing a very small amount of the data (4.57% of the initial database). We subsequently fit the ETH model [38] to the truncatedπ±p elastic-scattering databases. The model-parameter values show reasonable stability when subjected to different criteria for the rejection of single data points and entire data sets. Our result for the pseudovector πNN coupling constant is 0.0726±0.0014. We extract the scattering lengths and volumes, as well as the s- and p-wave hadronic phase shifts up to T = 100 MeV. Large differences in the s-wave part of the interaction can be seen when comparing our hadronic phase shifts with the current SAID solution (WI08);there is general agreement in the p waves, save for the ~1/21- hadronic phase shift.

Positron-Impact Ionization of Atomic Hydrogen in a Bichromatic Laser Field in the Second Born Approximation

The positron impact-ionization of atomic hydrogen in the presence of a linearly polarized bichromatic field is investigated in the second Born approximation. The field is composed of a fundamental frequency and its second harmonic. The state of positron in the field is described by the Volkov wavefunction, and the continuum state of the ejected electron is described by the Coulomb—Volkov wavefunction. The dressed ground state of target is a first order time-dependent perturbative wavefunction. The triple differential cross sections and their dependencies on laser field parameters are discussed. Numerical results demonstrate that the second-order effect plays a crucial role in understanding the laser-assisted positron scattering process.

Electron Acceleration in the Bubble Regime with Dense-Plasma Wall Driven by an Ultraintense Laser Pulse

An optimizing scheme for electron acceleration in the wake bubble with dense-plasma wall driven by an ultraintense laser pulse is presented and investigated by particle-in-cell simulation. The wall has an inner diameter matching the expected lateral bubble size. The bubble shape can be transversely controlled and longitudinally shrunk. The accelerated electrons as a bunch have a high quality because the electrons almost stay close to the bottom of the bubble and are accelerated to much high energy with narrow energy spread.