QCD Sum Rules, a Modern Perspective

Abstract

An introduction to the method of QCD sum rules is given for those who want to learn how to use this method. Furthermore, we discuss various applications of sum rules, from the determination of quark masses to the calculation of hadronic form factors and structure functions. Finally, we explain the idea of the light-cone sum rules and outline the recent development of this approach.to be published in the Boris Ioffe Festschrift "At the Frontier of Particle Physics / Handbook of QCD", edited by M. Shifman (World Scientific, Singapore, 2001)

Determining 1−−heavy hybrid masses via QCD sum rules

“…Here, s 0 is the threshold cutoff introduced to remove the contribution of the higher excited and continuum states [33].…”

“…Of the two-and three-gluon condensates we take both the prevailing values [33] α s G 2 = 0.038 ± 0.011 GeV 4 , g 3 s G 3 = 0.045 GeV 6 (12) and also recently obtained ones [34], i.e.,…”

“…Normally, the f cont (M 2 B ) is required to be 70% more to suppress the contributions of higher resonances and continuum. Figures A and B correspond to the gluon condensates from [33] and [34], i.e. Eqs.…”

“…(13), respectively. Figures A and B correspond to the gluon condensates from [33] and [34], i.e. Eqs.…”

Reconstruction of heavy quark current correlators at

“…Moments in the low energy expansion can be used for precise extractions of charm and bottom quark masses via sum rules [1] (for reviews see [2,3,4]), whereas threshold and high energy expansions are directly related to production cross sections for tt, charmed hadrons or bottom hadrons in the respective energy regions.…”