München 2006 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 36: Theorie
HK 36.3: Vortrag
Mittwoch, 22. März 2006, 17:30–17:45, B
Light Cone Sum Rules for γ*N → Δ Transition Form Factors — •Gerhard Peters1, Vladimir Braun1, Alexander Lenz1, and Anatoly Radyushkin2,3 — 1Universitaet Regensburg, D-93040 Regensburg — 2Old Dominion University, Norfolk, VA 23529 — 3Jefferson Laboratory, Newport News, VA 23606, USA
In this talk a theoretical framework is suggested for the calculation of γ*N → Δ transition form factors using the light-cone sum rule approach. Leading-order sum rules are derived and compared with the existing experimental data. We find that the transition form factors in a several GeV region are dominated by the “soft” contributions that can be thought of as overlap integrals of the valence components of the hadron wave functions. Our results for the dominant magnetic form factor GM(Q2) are rather close to the experimental data in the region above Q2 ∼ 2 GeV2. We believe that the light-cone sum rule approach currently offers the best compromise between theoretical rigor and the applicability to present and planned experiments involving elastic and transition form factors for baryons. One goal of such studies is to determine nucleon distribution amplitudes from the data on form factors, similar as parton distributions are extracted from the measured deep inelastic structure functions. This work presents a step in this direction.