不會搞錯了吧﹖ Nonlocal condensate model for QCD sum rules Ron-Chou Hsieha, , and Hsiang-nan Lia, b, c, d, a Institute of Physics, Academia Sinica, Taipei, Taiwan 115, PR China b Department of Physics, National Tsing-Hua University, Hsinchu, Taiwan 300, PR China c Department of Physics, National Cheng-Kung University, Tainan, Taiwan 701, PR China d Institute of Applied Physics, National Cheng-Chi University, Taipei, Taiwan 116, PR China Received 4 June 2010; revised 26 January 2011; accepted 26 February 2011. Editor: J.-P. Blaizot. Available online 8 March 2011. Abstract We include effects of nonlocal quark condensates into QCD sum rules (QSR) via the Källｅn–Lehmann representation for a dressed fermion propagator, in which a negative spectral density function manifests their nonperturbative nature. Applying our formalism to the pion form factor as an example, QSR results are in good agreement with data for momentum transfer squared up to Q2≒10 GeV2. It is observed that the nonlocal quark condensate contribution descends like 1/Q2, different from the exponential decrease in Q2 obtained in the literature, and contrary to the linear rise in the local-condensate approximation. Keywords: QCD sum rules; Nonlocal condensate; Dressed propagator http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TVN-52BGCNJ-1&_user=3846826&_coverDate=03%2F08%2F2011&_rdoc=9&_fmt=high&_orig=browse&_origin=browse&_zone=rslt_list_item&_srch=doc-info(%23toc%235539%239999%23999999999%2399999%23FLA%23display%23Articles)&_cdi=5539&_sort=d&_docanchor=&_ct=45&_acct=C000061542&_version=1&_urlVersion=0&_userid=3846826&md5=bf7c3c9eb79ed8aefe7d838ac930ffa5&searchtype=a -- 萬裡旌旗耀眼開 王師出境島夷催 揚鞭遙指花如許 諸葛前身今又來 策馬奔車走八荒 遠征功業邁秦皇 澄清宇宙安黎庶 先挽長弓射夕陽 ※ 來源:‧水木社區 http://newsmth.net‧[FROM: 141.2.246.*]