The form factors of the process {gamma}*{gamma}*{yields}{pi}{sup 0} for small virtuality of one of the photons and QCD sum rules (1): the structure of the infrared singularities
Radyushkin, A V [Joint Inst. for Nuclear Research, Dubna (Russian Federation). Lab. of Theoretical Physics]; Ruskov, R [Bylgarska Akademiya na Naukite, Sofia (Bulgaria). Inst. za Yadrena Izsledvaniya i Yadrena Energetika]
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; FORM FACTORS; SUM RULES; PHOTON-PHOTON INTERACTIONS; ASYMPTOTIC SOLUTIONS; FACTORIZATION; FEYNMAN DIAGRAM; GAMMA DECAY; INFRARED DIVERGENCES; PHOTONS; PIONS NEUTRAL; QUANTUM CHROMODYNAMICS; VIRTUAL STATES; 662230
We extend the QCD sum rule analysis of the form factor F{sub {gamma}*}{gamma}{sub *{yields}{pi}{sup 0}}(q{sub 1}{sup 2},q{sub 2}{sup 2}) into the region of small virtuality of one of the photons, where one should perform more precisely an OPE to factorize large and small distance contributions. As a first step the form factor is investigated in the region of moderate virtualities and the full corrections in the sum rule are obtained. It is shown that the infrared mass singularities are subtracted in the corresponding OPE for essentially nonsymmetric kinematics due to the operators of lowest two twists. On a simple scalar example the most important steps of the further calculations are demonstrated. 26 refs.; 8 figs.
Joint Inst. for Nuclear Research, Dubna (Russian Federation). Lab. of Theoretical Physics
OSTI; NTIS (US Sales Only); INIS
JINR
1993-12-31
English
Technical Report
Other Information: DN: Submitted to Yad. Fiz.; PBD: 1992
Medium: X; Size: 20 p.
ON: DE94609665
JINR-E-2-92-425
Other: ON: DE94609665; TRN: RU9305396004149
INIS; SCA: 662230; PA: AIX-25:004149; EDB-94:015721; ERA-19:005631; NTS-94:014784; SN: 93001121081
2008-02-12
10109860