A 480 ms isomeric 29/2−-state of the(p_{1/2}^{ - 2} )_{0^ + } f_{5/2}^{ - 1} (i_{13/2}^{ - 2} )_{12^ + } configuration in203Pb

A new, 480 ms, 29/2^? isomeric level has been found in²⁰³Pb at an excitation energy of 2950.1 keV by bombarding²⁰⁴Hg with α-particles in the energy range 45–55 MeV using the Stockholm 225-cm cyclotron. This 29/2^? state is suggested to be mainly due to the configuration (p ₁ ^2/?2 f ₅ ^2/?1 i ₁₃ ^2/?2 )₁₂. The 29/2^? state decays predominantly by a 153.4 keV M2 transition to a 23/2^? level and by a 1027.5 keV M4 transition to a 21/2⁺ level, followed by two E2 transitions of energies 258.6 keV and 838.7 keV, respectively, to the previously known 13/2⁺, 6.4 s isomeric level. The decay scheme of the 29/2^? isomeric state is based on experimental information obtained from total and delayedγ-ray intensities,γγ-coincidences, excitation functions, lifetime and delayed conversion electron measurements. The presence of the 29/2^? level confirms an essential and expected feature of the shell model for five neutron holes added to the²⁰⁸Pb-core.     

Neutron Pairing Correlations in an {\alpha}–{n}–{n} Three-Cluster Model of the {^{6}}He Nucleus

An \({\alpha}\)–n–n three-cluster model of the \({^6}\)He nucleus is studied by solving the Faddeev equations, where the cluster potential between \({\alpha}\) and n takes into account the Pauli exclusion correction, using the Fish-Bone Optical Model (Schmid in Z Phys A 297:105, 1980). The resulting binding energy of the ground state (\({0^+}\)) is 0.831 MeV and the resonance energy of the first excited state (\({2^+}\)), 0.60–i0.012 MeV, is extracted from the three-cluster break-up threshold. These theoretical values are in reasonable agreement with the experimental data: 0.973 MeV and 0.824–i0.056 MeV, respectively. In order to investigate the structure of these states, we calculate the angle density matrix for the \({\angle n_1 \alpha n_2}\) angle in the triangle formed by the three clusters. The angle density matrix of the ground state has two peaks and the configuration of \({0^+}\) wave function corresponding to the peaks constitutes a mixture of an acute-angled triangle structure and an obtuse-angled one. This finding is consistent with the former result from a variational approach (Hagino and Sagawa in Phys Rev C 72:044321, 2005). On the other hand, in the case of \({2^+}\) state only a single peak is obtained.     

$\mathcal{PT}$-Symmetric Quantum Electrodynamics—$\mathcal{PT}$QED

The construction of PT\mathcal{PT}-symmetric quantum electrodynamics is reviewed. In particular, the massless version of the theory in 1+1 dimensions (the Schwinger model) is solved. Difficulties with unitarity of the S-matrix are discussed.     

PHENIX J/Ψ measurement at \sqrt {s_{NN} } = 200 GeV

In 2002, PHENIX had the first measurements on J/Ψ → e⁺ e^? and J/Ψ→μ ⁺ μ ^? in AuAu and pp collisions at $\sqrt {s_{NN} } = 200$ GeV. The preliminary results are presented and discussed. The ongoing analysis status on year 2003 dAu collision data are presented.     

Untersuchung des ZerfallsBi^{212} (ThC)\xrightarrow{\beta }Po^{212} (ThC')\xrightarrow{\alpha }Pb^{208} (ThD) durch (γ, α)-Koinzidenzen

Theγ-spektrum of Po²¹² (ThC′) has been measured by (γ, α)-coincidences with a fast-slow coincidence apparatus. The results are in excellent agreement with the conversion lines found by theLatyshev group. The absoluteγ-intensities have also been determined in order to get spins and parities of the levels by calculating the absolute conversion coefficients. Theβ-intensity leading to the exited states of Po²¹²(ThC′) is estimated to be about one third of that measured byBurde andRozner by (β, α)-coincidences. Threeγ-lines measured byChinaglia andDemichelis by (γ, α)-coincidences do not agree with our results. The 2⁺ assignment of the first exited state is now well established, but for the other levels in the decay scheme there is still some uncertainty concerning spin and level assignment.     

Analysis of the vertexes \Xi_{Q}^{*}′QV , \Sigma_{Q}^{*} \Sigma_{Q}^{}V and radiative decays \Xi_{Q}^{*} \rightarrow ′Q \gamma , \Sigma_{Q}^{*} \rightarrow \Sigma_{Q}^{} \gamma

In this article, we study the vertexes $ \Xi_{Q}^{*}$ ′_Q V and $ \Sigma_{Q}^{*}$ $ \Sigma_{Q}^{}$ V with the light-cone QCD sum rules, then assume the vector meson dominance of the intermediate $ \phi$ (1020) , $ \rho$ (770) and $ \omega$ (782) , and calculate the radiative decays $ \Xi_{Q}^{*}$ $ \rightarrow$ ′_Q $ \gamma$ and $ \Sigma_{Q}^{*}$ $ \rightarrow$ $ \Sigma_{Q}^{}$ $ \gamma$ .     

Improving anti-reflectivity and laser damage threshold of \hbox {SiO}_{2}/\hbox {ZrO}_{2} thin films by laser shock peening at 1064 nm

In this study, anti-reflection (AR) \(\hbox {SiO}_{2}/ \hbox {ZrO}_{2}\) thin films with 3-layers were designed and fabricated by the essential Macleod software and physical vapor deposition, respectively. In order to improve the optical and physical properties of the prepared samples, laser shock peening (LSP) technique was applied. For this purpose, an Argon Fluoride Excimer laser \((\lambda =193 \,\text {nm})\) with 110 and 240 mJ energies and 1 Hz frequency at different pulses was used. The effect of LSP method in improving transmissions and laser damage thresholds of the prepared samples was proved by using UV–Vis–IR spectroscopy in the wavelength range of 400–1200 nm and international standard ISO11254 at 1064 nm. In addition, scanning electron microscopy was used to check the effect of applying LSP.     

Beam-target double-spin asymmetry A{LT} in charged pion production from deep inelastic scattering on a transversely polarized {3}He target at 1.4<Q{2}<2.7 GeV{2}

We report the first measurement of the double-spin asymmetry A{LT} for charged pion electroproduction in semi-inclusive deep-inelastic electron scattering on a transversely polarized {3}He target. The kinematics focused on the valence quark region, 0.16相似文献   

Finite Size XXZ Spin Chain with Anisotropy Parameter Δ= \frac{1} {2}

We find an analytic solution of the Bethe–Ansatz equations (BAE) for the special case of a finite XXZ spin chain with free boundary conditions and with a complex surface field which provides for U_q(sl(2)) symmetry of the Hamiltonian. More precisely, we find one nontrivial solution, corresponding to the ground state of the system with anisotropy parameter Δ= $\frac{1}{2}$ corresponding to q³=?1. With a view to establishing an exact representation of the ground state of the finite size XXZ spin chain in terms of elementary functions, we concentrate on the crossing parameter η dependence around η=π/3 for which there is a known solution. The approach taken involves the use of a physical solution Q of Baxter's T-Q equation, corresponding to the ground state, as well as a non-physical solution P of the same equation. The calculation of P and then of the ground state derivative is covered. Possible applications of this derivative to the theory of percolation have yet to be investigated. As far as the finite XXZ spin chain with periodic boundary conditions is concerned, we find a similar solution for an assymetric case which corresponds to the 6-vertex model with a special magnetic field. For this case we find the analytic value of the “magnetic moment” of the system in the corresponding state.     

Three-Body Baryonic B ̄ 0 → Λ c + p ̄ π 0 $\bar {B}^{0}\rightarrow {{\varLambda }}^{+}_{c} \bar {p} \pi ^{0}$ Decay

International Journal of Theoretical Physics - We study the three-body baryonic decay $ \bar {B}^{0}\rightarrow {{\varLambda }}^{+}_{c} \bar {p} \pi ^{0}$ based on the factorization approach. The...     

用PVTX装置研究二元混合物的汽液平衡——由{PvTX}推算{TPxy}

混合工质的TPvX数据和汽液平衡(TPxy)数据是两类重要的热力学基础数据。前者主要用PVTX装置测定,后者则用汽液平衡釜结合色谱分析得到,但一般限于中、低压范围.倘用PVTX装置来研究混合工质的汽液平衡,由于其测量方便,精度高以及温度压力范围广,有其独特优点.常用的定容线斜率分析法和直接观察法,只能产生泡点(TPx)或露点(TPy)数据,而x、y不可兼得,要得全面的汽液平衡关系,实验量太大,因而此法受到限制.本文提出探讨的一种方法,由PVTX装置测定的两相区实验数据PvTX(X为混合物总组成)直接推算汽液平衡的TPxy数据,可以弥补前述方法的缺陷,直接提供高温高压汽液平衡数据,并把PvTX和TPxy两类数据统一起来研究.     

Semi-Classical Twists for {\mathfrak{sl}}_{3} and {\mathfrak{sl}}_{4} Boundary r-Matrices of Cremmer–Gervais Type

We obtain explicit formulas for the semi-classical twists deforming the coalgebraic structure of $U({\mathfrak{sl}}_{3})$ and $U({\mathfrak{sl}}_{4})$ . In rank 2 and 3 the corresponding universal R-matrices quantize the boundary r-matrices of Cremmer–Gervais type defining Lie Frobenius structures on the maximal parabolic subalgebras in ${\mathfrak{sl}}_{n}$ .     

Why is \mathcal{CPT} Fundamental?

Lüders and Pauli proved the theorem based on Lagrangian quantum field theory almost half a century ago. Jost gave a more general proof based on “axiomatic” field theory nearly as long ago. The axiomatic point of view has two advantages over the Lagrangian one. First, the axiomatic point of view makes clear why is fundamental—because it is intimately related to Lorentz invariance. Secondly, the axiomatic proof gives a simple way to calculate the transform of any relativistic field without calculating , and separately and then multiplying them. The purpose of this pedagogical paper is to “deaxiomatize” the theorem by explaining it in a few simple steps. We use theorems of distribution theory and of several complex variables without proof to make the exposition elementary.     

Renormalisation of Φ4-Theory on Non-Commutative $$\mathbb{R}^{4}$$ to All Orders

We present the main ideas and techniques of the proof that the duality-covariant four-dimensional non-commutative ⁴-model is renormalisable to all orders. This includes the reformulation as a dynamical matrix model, the solution of the free theory by orthogonal polynomials as well as the renormalisation byflow equations involving power-counting theorems for ribbon graphs drawn on Riemann surfaces     

同时暴露{101}与{001}面的TiO_2纳米晶体光催化还原CO_2实验研究

光催化还原CO_2技术是一项极有前景的可再生能源技术,其不仅能减少CO_2排放,还能提供可再生能源。本文利用溶剂热法制备了具有不同{001}/{101}晶面比例的TiO_2纳米晶体,使用X射线衍射仪(XRD),透射电镜(TEM),比表面与孔径分析仪(BET)及光致发光光谱(PL)等手段对其进行表征,在紫外光照射下的连续流反应系统中进行了CO_2光催化还原实验。实验结果表明,合适的{001}/{101}晶面比例可抑制光生电子空穴对的复合,明显提高TiO_2晶体光催化还原CO_2活性。     

天然金刚石平行{100}的正常生长

利用同步辐射对天然金刚石晶体进行了形貌学研究,在近完事晶体内观察到晶体以平行{100}生长为主的正常生长,而不是前人所常见的平行{111}生长。生长带方向平行于（100）、（100）和（010）、（010）。生长带分布在偏离晶体中心的曲面内。由生长带的分布与形态可以观察到晶体不同晶面的生长速度具有明显差异。