Nonlocal condensates & QCD sum rules for the pion wave function
The QCD-sum-rule calculation of the pion wave function by Chernyak and Zhitnitsky (CZ) implicitly assumes that the correlation length of vacuum fluctuations is large compared to the typical hadronic scale {similar_to}1/{ital m}{sub {rho}}, so that one can substitute the original nonlocal objects such as {l_angle}{ital {bar q}}(0){ital q}({ital z}){r_angle} by constant {l_angle}{ital {bar q}}(0){ital q}(0){r_angle}-type values. We outline a formalism enabling one to work directly with the nonlocal condensates, and construct a modified sum rule for the moments {l_angle}{xi}{sup {ital N}}{r_angle} of the pion wave function. The results are rather sensitive to the value of the parameter {lambda}{sub {ital q}}{sup 2}={l_angle}{ital {bar q}D}{sup 2}{ital q}{r_angle}/{l_angle}{ital {bar q}q}{r_angle} specifying the average virtuality of the vacuum quarks. Varying it from the most popular value {lambda}{sub {ital q}}{sup 2}=0.4 GeV{sup 2} up to the value {lambda}{sub {ital q}}{sup 2}=1.2 GeV{s
- Research Organization:
- Thomas Jefferson Lab National Accelerator Facility
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-84ER40150
- OSTI ID:
- 954241
- Report Number(s):
- CEBAF-TH-91-10
- Journal Information:
- Physical Review D, Journal Name: Physical Review D Vol. 45
- Country of Publication:
- United States
- Language:
- English
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