精确计算重整化N-N圈链传播下pp→π^+π^-反应微分截面(英文)  

Accurate Calculation of the Differential Cross-Section of pp→π^+π^- Reaction with N-N Renormalized Loop-chain Contribution

作　　者：张家伟[1] 刘春兰[1] 陈学文[1] 

机构地区：[1]重庆科技学院物理系,重庆401331

出　　处：《重庆师范大学学报（自然科学版）》2013年第2期96-101,共6页Journal of Chongqing Normal University:Natural Science

基　　金：Research Foundation of Chongqing University of Science & Technology(No.CK2011B34);Natural Science Foundation Project of CQ CSTC(No.CSTC2012jjB40006)~~

摘　　要：本文在量子场论微扰理论框架下,利用荷电介子与核子(π±N)强相互作用的SU(2)-不变耦合模型,系统研究了pp→π+π-物理反应过程。采用"大动量积分极限法"对核子—反核子(N-N)重正化圈—链图传播子做了相关物理分析并作了严格解析计算,获得了精确理论计算结果。进而利用该结果系统计算了在核子—反核子(N-N)重整化圈—链图传播子下pp→π+π-反应的微分截面,并获得了一个简洁解析的结果dσ(chain)dΩ=G4/641/(2π)21/p20p20-μ2/p20-m21/(2p20-μ2-2p20-m2p20-μ2cos θ)2T(q2)。另外,也计算了在不同质心能量下pp→π+π-反应树图,单圈图和链图的微分截面,并做了相关比较和讨论,获得了十分重要的辐射修正信息,其中,p0在很大的能量2.5GeV≤p0≤100GeV范围内,链图和圈图对树图截面的修正都在合理的范围内,即R(chain)(or R(loop))<2.0。这些结果对于深入研究SU(2)-不变耦合模型中强相互作用理论以及探索介子与核子(πN)间反应截面问题具有一定的参考价值。此外,还将对量子场论微扰理论在核子相互作用描述的适用范围以及重正化计算的不同方式与计算途径等相关物理问题提供有效参考。In the work, we make a detailed discussion on the reaction, via nucleon-antinucleon propagator, within the SU （2）-invariant coupling model between charged mesons and nucleons （π^± N） of perturbation theory of quantum field theory. The renormalized loop-chain propagator of nucleon-antinucleon （N-N^-） was strictly calculated and given an analytical expression with the large momentum integral limitation method. Furthermore, we obtain a simple and analytic expression of the differential cross-section of pp^-→π^＋π^- with nucleon-antinucleon （N-N^-） renormalized loop-chain propagator, i. e.dσ（chain）/dΩ=G^4/64 1/（2π）^21/p0^2√p0^2-μ^2/√p0^2-m^2 1/（2p0^2-μ^2-2√p0^2-m^2√p0^2-μ^2cosθ）^2T（q^2）.We also calculate and obtain numerical resuits of the differential cross-section of pp^-→π^＋π^- at tree, one-loop and chain diagram in different center-of-mass energy, respectively, and make a detailed comparison and discussion and show some important information about radiative correc- tion. In large energy within 2.5 GeV∈p0∈100 GeV, these corrections are in the reasonable range, i.e. R（chain）（of R（loop））〈2.0. The results provide a significant reference to understand in-depth of the SU（2）-invariant coupling model of strong interac- tions theory and to explore the reaction cross-section between mesons and nucleons （πN）. In addition, it will provide effective reference to the applicability of the perturbation theory of quantum field theory in nucleon interactions, the renormalized calculation in different ways and approaches.

关 键 词：SU(2)-不变耦合模型 圈—链图传播子 重整化 微分截面 辐射修正 

分 类 号：O572.24[理学—粒子物理与原子核物理]