高能核碰撞中带电多重数快度与能量和中心度的关系

用强子–弦级联模型JPCIAE及相应的Monte Carlo事例产生器研究相对论性核–核碰撞中带电粒子多重数的赝快度密度对能量和中心度的依赖关系.无需另调任何模型参数的条件下,此模型可以同时较好地描述相对论性pp实验数据及PHOBOS和PHENIX实验组的Au+Au实验数据.本文指出:因〈N_part〉并非严格定义的物理量,致使实验上和理论上确定〈N_part〉有一定任意性,从而使得每参加者核子对的带电粒子赝快度密度随着〈N_part〉的增加可能逐渐增大,也可能逐渐减小,因此用它来区分粒子产生机制是欠妥的.     

On the exceptional zeros of cross-products of derivatives of spherical Bessel functions

The lowest zeros of the cross-products of derivatives of spherical Bessel functions are not obtainable from a McMahon-type formula. This paper derives an analytical approximation for these lowest, exceptional, zeros, through to 4th order in a parameter specifying the thinness of the corresponding concentric spherical region.

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Zusammenfassung Die kleinsten Nullstellen der Kreuzprodukte der Ableitungen von spherischen Bessel-funktionen können nicht durch eine Formel von McMahon Typ erhalten werden. Durch eine Entwicklung bis zu vierter Ordnung in einem Parameter proportional zur Dicke des zugeordneten spherischen Gebietes berechnen wir eine analytische Näherung für diese kleinsten, außergewöhnlichen, Nullstellen.

     

A hydrogenation product derived from the diterpenoid barbatusin:A revised structure

The structure of the hydrogenation product of barbatusin, a diterpenoid from Coleus barbatus Bentham has been revised on the basis of NMR and X-ray data. A geminal coupling of unusually high magnitude has been observed and analysed.     

Gauge theory of fermions onR × S 3 spacetime

A Lorentz-invariant gauge theory for massive fermions on R × S ³ spacetime is built up. Using the symmetry of S ³,we obtain Dirac-type equation and derive the expression of the fermionic propagator. Finally, starting from the SU(N) gauge-invariant Lagrangian, we obtain the set of Dirac-Yang-Mills equations on R × S ³ spacetime, pointing out major differences from the Minkowskian case.