Nucleon distribution amplitudes and their application to nucleon form factors and theN→Δtransition at intermediate values ofQ2

Abstract

We compare a recent lattice determination of the nucleon distribution amplitudes with other approaches and models. We study the nucleon distribution amplitudes up to twist 6 in next-to-leading conformal spin and we also investigate conformal d-wave contributions to the leading-twist distribution amplitude. With the help of light-cone sum rules one can relate the distribution amplitudes to the form factors of the nucleon or the N ! Á transition at intermediate values of the momentum transfer. We compare our results with experimental data in the range 1 GeV 2 Q 2 10 GeV 2 . Keeping in mind that we are working only in leading order QCD and next-to-leading order QCD corrections might be sizeable, we already obtain a surprisingly good agreement for the nucleon form factors G

Form factors and strong couplings of heavy baryons from QCD light-cone sum rules

“…The nucleon → vacuum matrix element of a three-quark operator with light-like separations (z 2 → 0) has the following decomposition [5,9]:…”

“…The resulting decomposition contains altogether 27 DA's. We use their expressions obtained in [6,9] to the next-to-leading order in the conformal spin expansion. The three twist-3 DA's V 1 , A 1 , T 1 are presented in eq.…”

“…The latter have been worked out in [5,6]. This approach was applied to the nucleon electromagnetic form factors [7,8,9], where the second nucleon in the correlation function was interpolated with the three-quark current e.g., with the Ioffe current [10]. In order to access heavy baryons, e.g., Λ c or Λ b , one has to use a three-quark current with one heavy c or b quark.…”

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“…The cross section turns out to very sensitive to the form of the input phenomenological solution for nucleon DA. We show the results for Chernyak-Ogloblin-Zhitnitsky (COZ) [18] (long blue dashes); King-Sachrajda (KS) [19] (solid green line); Braun-Lenz-Wittmann nextto-leading-order (BLW NLO) [20] (medium orange dashes) and NNLO modification [21] of BLW (short brown dashes). The solutions close to the asymptotic form of the nucleon DA φ(y i ) = 120y 1 y 2 y 3 result in a very small cross section, while those significantly different from the asymptotic form like COZ and KS result in larger cross sections.…”

Baryon-to-Meson Transition Distribution Amplitudes: Formalism and Models

“…The cross section turns out to very sensitive to the form of the input phenomenological solution for nucleon DA. We show the results for Chernyak-Ogloblin-Zhitnitsky (COZ) [18] (long blue dashes); King-Sachrajda (KS) [19] (solid green line); Braun-Lenz-Wittmann next-to-leading-order (BLW NLO) [20] (medium orange dashes) and NNLO modification [21] of BLW (short brown dashes). The solutions close to the asymptotic form of the nucleon DA φ(y i ) = 120y 1 y 2 y 3 result in a very small cross section, while those significantly different from the asymptotic form like COZ and KS result in larger cross sections.…”