Liu B C, Zou B S
Institute of High Energy Physics, P.O. Box 918(4), Beijing 100049, China.
Phys Rev Lett. 2006 Feb 3;96(4):042002. doi: 10.1103/PhysRevLett.96.042002. Epub 2006 Jan 31.
Using a resonance isobar model and an effective Lagrangian approach, from recent BES results on J/psi-->ppeta and psi-->pK+Lamda, we deduce the ratio between effective coupling constants of N*(1535) to KLamda and peta to be R=gN*(153)KLamda/gN*(1535)peta=1.3+/-0.3. With the previous known value of gN*(1535)peta, the obtained new value of gN*(1535)KLamda is shown to reproduce recent pp-->pK+Lamdanear-threshold cross section data as well. Taking into account this large NKLamda coupling in the coupled channel Breit-Wigner formula for the N(1535), its Breit-Wigner mass is found to be around 1400 MeV, much smaller than the previous value of about 1535 MeV obtained without including its coupling to KLamda. The implication on the nature of N*(1535) is discussed.
利用共振同位旋模型和有效拉格朗日方法，根据北京谱仪（BES）近期关于J/ψ→ppη和ψ→pK⁺Λ的结果，我们推导出N*(1535)与KΛ以及η的有效耦合常数之比为R = gN*(153)KΛ / gN*(1535)η = 1.3±0.3。结合之前已知的gN*(1535)η值，所得到的gN*(1535)KΛ新值也能重现近期pp→pK⁺Λ接近阈能处的截面数据。考虑到在N*(1535)的耦合道布莱特-维格纳公式中这种较大的NKΛ耦合，发现其布莱特-维格纳质量约为1400 MeV，远小于之前未考虑其与KΛ耦合时得到的约1535 MeV的值。文中还讨论了这一结果对N(1535)性质的影响。
