Exploring lightcone sum rules for pion and kaon form factors
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Abstract
We analyze the highertwist effects and the SU(3)flavor symmetry breaking in the correlation functions used to calculate form factors of pseudoscalar mesons in the QCD lightcone sum rule approach. It is shown that the Ward identities for these correlation functions yield relations between twist4 twoand threeparticle distribution amplitudes. In addition to the relations already obtained from the QCD equations of motions, we have found a new one. With the help of these relations, the twist4 contribution to the lightcone sum rule for the. pion electromagnetic form factor: is reduced to a very simple form. Simultaneously, we correct a sign error in an earlier calculation. The updated lightcone sum rule prediction for the pion form factor at intermediate momentum transfers is compared with the recent Jefferson Lab data. Furthermore, from the correlation functions with strangequark currents the kaon electromagnetic form factor and the K > pi weak transition form factors are predicted with O(m(s)) similar to O(m(K)(2)) accuracy.
Details
Authors  

Organisations  
Research areas and keywords  Subject classification (UKÄ) – MANDATORY

Original language  English 

Pages (fromto)  6779 
Journal  European Physical Journal C. Particles and Fields 
Volume  26 
Issue number  1 
State  Published  2002 
Peerreviewed  Yes 