Quantum scattering in one-dimensional systems satisfying the minimal length uncertainty relation

In quantum gravity theories, when the scattering energy is comparable to the Planck energy the Heisenberg uncertainty principle breaks down and is replaced by the minimal length uncertainty relation. In this paper, the consequences of the minimal length uncertainty relation on one-dimensional quantum scattering are studied using an approach involving a recently proposed second-order differential equation. An exact analytical expression for the tunneling probability through a locally-periodic rectangular potential barrier system is obtained. Results show that the existence of a non-zero minimal length uncertainty tends to shift the resonant tunneling energies to the positive direction. Scattering through a locally-periodic potential composed of double-rectangular potential barriers shows that the first band of resonant tunneling energies widens for minimal length cases when the double-rectangular potential barrier is symmetric but narrows down when the double-rectangular potential barrier is asymmetric. A numerical solution which exploits the use of Wronskians is used to calculate the transmission probabilities through the Pöschl–Teller well, Gaussian barrier, and double-Gaussian barrier. Results show that the probability of passage through the Pöschl–Teller well and Gaussian barrier is smaller in the minimal length cases compared to the non-minimal length case. For the double-Gaussian barrier, the probability of passage for energies that are more positive than the resonant tunneling energy is larger in the minimal length cases compared to the non-minimal length case. The approach is exact and applicable to many types of scattering potential.     

Diffraction patterns of laser beams with thermal self-phase modulation by optically thin films

Summary A mathematical model of the far-field diffraction pattern of a laser beam with laser heating self-phase modulation through an optically thin film is presented. We deal with the steady-state temperature field generated by the weak absorption of a laser beam in an optically and thermally thin film bounded by two transparent plates, the cell walls, whose thermal exchange to the surrounding ambient has been assumed to be linear in the temperature difference to the ambient. These hypotheses describe the application of the steady-state ?thermal lens? spectroscopy to the detection of the optical or thermal properties of liquid samples. We give a very simple expression for the diffracted intensity that appears suitable for fast computer calculations. The good accuracy of the technique is shown by comparison with the results given by more intricate approaches. To speed up publication, the authors of this paper have agreed to not receive the proofs for correction.     

One-loop formulas for H → Zνlνl for l = e, μ, τ in 't Hooft-Veltman gauge

In this paper, we present analytical results for one-loop contributions to the decay processes \begin{document}$ H\rightarrow Z \nu_l\bar{\nu}_l $\end{document} (for \begin{document}$ l = e, \mu, \tau $\end{document}). The calculations are performed within the Standard Model framework in the 't Hooft-Veltman gauge. One-loop form factors are then written in terms of scalar one-loop functions in the standard notations of \begin{document}$ {\tt LoopTools}$\end{document}. As a result, one-loop decay rates for the decay channels can be evaluated numerically by using the package. Furthermore, we analyze the signals of \begin{document}$ H\rightarrow Z \nu_l\bar{\nu}_l $\end{document} via the production processes \begin{document}$ e^-e^+ \rightarrow ZH^* \rightarrow Z (H^* \rightarrow Z \nu_l\bar{\nu}_l) $\end{document}, including the initial beam polarizations at future lepton colliders. The Standard Model backgrounds, such as the processes \begin{document}$ e^-e^+ \rightarrow \nu_l\bar{\nu}_l ZZ $\end{document}, are also examined in this study. Numerical results indicate that one-loop corrections make contributions of approximately 10% to the decay rates. These are sizeable contributions and should be taken into account at future colliders. We show that the signals \begin{document}$ H\rightarrow Z\nu_l\bar{\nu}_l $\end{document} are clearly visible at the center-of-mass energy \begin{document}$ \sqrt{s}=250 $\end{document} GeV and are difficult to probe in higher-energy regions owing to the dominant backgrounds.     

中国极化电子—离子对撞机

电磁相互作用把质子与电子束缚起来,形成氢原子。人类对于电磁相互作用的深刻认识发展出智能手机和信息技术,给日常生活带来了极大的便利。相比之下,夸克和胶子如何被强相互作用束缚从而形成质子与中子,人类还缺乏充分的认识。因此,全球的中高能核物理学家提出了建设未来高精度极化电子—离子对撞机以对其进行更深入的研究。文章主要介绍中国极化电子—离子对撞机实验上的物理问题,以及量子色动力学格点计算在这些物理研究中的重要作用。     

CP violation in correlated production and decay of unstable particles

We study resonant CP-violating Einstein-Podolsky-Rosen correlations that may take place in the production and decay of unstable scalar particles at high-energy colliders. We show that as a consequence of unitarity and CPT invariance of the S-matrix, in 2→2 scatterings mediated by mixed scalar particles, at least three linearly independent decay matrices associated with the unstable scalar states are needed to obtain non-zero CP-odd observables that are also odd under C-conjugation. Instead, for the correlated production and decay of two unstable particle systems in 2→4 processes, we find that only two independent decay matrices are sufficient to induce a net non-vanishing CP-violating phenomenon. As an application of this theorem, we present numerical estimates of CP asymmetries for the correlated production and decay of supersymmetric scalar top-anti-top pairs at the LHC, and demonstrate that these could reach values of order one. As a byproduct of our analysis, we develop a novel spinorial trace technique, which enables us to efficiently evaluate lengthy expressions of squared amplitudes describing the resonant scalar transitions.     

国际直线对撞机研究现状及未来发展

文章介绍了国际直线对撞机(ILC)的科学目标及直线对撞机(LC)与强子对撞机(LHC)的关系.结合对正负电子直线对撞机历史的回顾及国际直线对撞机方案的选择,对国际直线对撞机的发展现状及未来发展趋势进行了介绍.对中国科学家在国际直线对撞机中所做的国际合作研究进行了简要的回顾,并强调了中国抓住国际直线对撞机国际合作机遇对中国科学发展的重要性.     

Associated production of a neutral top-Higgs with a heavy-quark pair in the γγ collisions at ILC

We have studied the associated production processes of a neutral top-Higgs in the topcolor assisted technicolor model with a pair of heavy quarks in γγ collisions at the International Linear Collider (ILC). We find that the cross section for ttht in γγ collisions is at the level of a few fb with the c.m. energy √s=1000 GeV, which is consistent with the results of the cross section of ttH in the standard model and the cross section of tth in the minimal supersymmetric standard model. It should be clear that hundreds of to thousands of ht per year can be produced at the ILC. This process of γγ→ttht is really interesting in testing the standard model and searching the signs of technicolor.     

关于标量介子的研究

基于a₀(980)和D^*_sJ(2317)属于1 ³P₀介子多重态这个主要假定, 在准线性Regge轨迹方案下估计了1 ³P₀介子多重态成员的质量. 在介子-介子混合的框架下,建议a₀(980), K^*₀(1052), f₀(1099)和f₀(530)组成基态标量介子九重态, 并且f₀(1099)主要由ss组成,而f₀(530)主要是uu+dd. 这些态可能分别对应已观察到的标量态a₀(980), κ(900), f₀(980)和f₀(600)/σ. 另外, 在胶球为主的图像下, 估计基态标量胶球的质量大约为1340MeV. 给出的结果与其他不同方法给出的结果是一致的.