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Upsilon衰變形狀因子的輻射修正

2018-01-17 10:42范旭
科技創(chuàng)新與應(yīng)用 2018年34期

范旭

摘 要:文章主要研究了基于非相對(duì)論量子色動(dòng)力有效理論(NRQCD)的?狀→?濁c+?酌衰變寬度的相對(duì)論修正。根據(jù)NRQCD因子化定理,能將一個(gè)本不計(jì)算過程的衰變寬度因子化為一系列短程系數(shù)與長(zhǎng)程矩陣元。短程系數(shù)可以微擾計(jì)算,長(zhǎng)程矩陣元雖不可計(jì)算但是普適的,可參考文獻(xiàn),從而計(jì)算?狀→?濁c+?酌過程領(lǐng)頭階相對(duì)論修正的衰變寬度。

關(guān)鍵詞:NRQCD;相對(duì)修正;衰變

中圖分類號(hào):O29 文獻(xiàn)標(biāo)志碼:A 文章編號(hào):2095-2945(2018)34-0016-02

Abstract: The relativistic correction of the decay width of ?狀→ηc+γ based on the effective theory of nonrelativistic quantum chromodynamics (NRQCD) is studied in this paper. According to the NRQCD factorization theorem, the decay width factor of a non-computational process can be reduced to a series of short range coefficients and long range matrix elements. The short range coefficient can be calculated by perturbation; although the long range matrix elements are not computable, they are universal and can be used to calculate the decay width of the first order relativistic correction of ?狀→ηc+γ process.

Keywords: NRQCD; relative correction; decay

本文主要計(jì)算了強(qiáng)相互作用的粒子的衰變中的幾個(gè)過程。過程中主要使用Mathematica程序軟件,其中包括了Feyncalc,F(xiàn)eyn-Arts,F(xiàn)IRE以及Package-X等高能軟件包,計(jì)算出?狀→?濁c+?酌過程的QED,QCD,以及QED+QCD的衰變寬度,包括領(lǐng)頭階計(jì)算與相對(duì)論修正計(jì)算。其中領(lǐng)頭階計(jì)算的結(jié)果在文獻(xiàn)1中已經(jīng)算出,而我采用自己的計(jì)算方法重復(fù)這個(gè)過程,得到的數(shù)據(jù)結(jié)果與文獻(xiàn)1相同,從而檢驗(yàn)了此方法的準(zhǔn)確性,確保了近一步計(jì)算的準(zhǔn)確性。

這結(jié)果只是計(jì)算的一部分,還需要完善其他幾個(gè)過程的修正計(jì)算,正在計(jì)算過程中,未來將修正計(jì)算更加完善。

參考文獻(xiàn):

[1]G. T. Bodiwin, E. Braaten, and G. P. Lepage,Rigorous QCD analysis of inclusive annihilation and production of heavy quarkonium.Phys.Rev.,1995,D51:1125-1171.

[2]Ying-Jia Gao ,Yu-Jie Zhang , and Kuang-Ta Chao Radiative decays of bottomonia into charmonia and light mesons [arXiv:0701009 [hep-ph]].

[3]W. L. Sang,Y. Q. Chen, Phys. Rev. D Particles & Fields, 2010, 81(81):034028-034028.