Spin Effects in High Energy Fragmentation Processes

Recent measurements, in particular those on $\Lambda$ polarization and spin alignment of vector mesons in $e^+e^-$ annihilation at LEP, and those on the azimuthal asymmetry at HERA, have attracted much attention on the spin effects in high energy fragmentation processes. In this talk, we make a brief introduction to the different topics studied in this connection and a short summary of the available data. After that, we present a short summary of the main theoretical results that we obtained in studying these different topics. The talk was mainly based on the publications [5-9] which have been finished in collaboration with C.Boros, Liu Chun-xiu and Xu Qing-hua.Comment: Plenary talk given at the 3rd Circum-Pan-Pacifc Symposium on High Energy Spin Physics, October 2001, 8 pages, 4 figure

Holography and chiral Lagrangian

In a wide class of holographic models described by the Yang-Mills and Chern-Simons terms, we derive all the ${\cal O}(p^6)$ Chiral Perturbation Theory low-energy constants. Various model-independent relations exist among the constants up to this order, generalizing the previously found relations at $p^4$ order. Some of them can be extended to relations between different amplitudes.Comment: 6 pages, contribution to the poster section of QCD@Work 2012 --International Workshop on QCD: Theory and Experiment--, 18-21 June 2012, Lecce (Italy

A geometric method to determine the direction of electric field due to a uniformly charged line segment

A geometrical approach to calculate the electric field due to a uniformly charged rod is presented. The result is surprisingly simple and elegant. Using pure geometrical quantities like length and angle, the direction of the electric field in this charge configuration can be graphically defined. Understanding and application of this result can lead to a deeper appreciation of symmetry in a seemingly unsymmetric system