QCD analysis of anti-p N ---> gamma* pi in the scaling limit
Apr, 200516 pages
Published in:
- Phys.Lett.B 622 (2005) 83-92
e-Print:
- hep-ph/0504255 [hep-ph]
Report number:
- CPHT-RR-023-0405
Citations per year
Abstract: (Elsevier)
We study the scaling regime of nucleon–antinucleon annihilation into a deeply virtual photon and a meson, p¯N→γ∗π , in the forward kinematics, where |t|≪Q2∼s . We obtain the leading twist amplitude in the kinematical region where it factorizes into an antiproton distribution amplitude, a short-distance matrix element related to nucleon form factor and the long-distance dominated transition distribution amplitudes which describe the nucleon to meson transition. We give the Q2 evolution equation for these transition distribution amplitudes. The scaling of the cross section of this process may be tested at the proposed GSI intense antiproton beam facility FAIR with the PANDA or PAX detectors. We comment on related processes such as πN→N′γ∗ and γ∗N→N′π which may be experimentally studied at intense meson beams facilities and at JLab or Hermes, respectively.Note:
- 15 pages, 1 .eps figure, to be published in Phys. Lett. B. Equation 23 corrected in version 3
- anti-p nucleon: annihilation
- pi: hadroproduction
- amplitude analysis: transition
- momentum transfer dependence
- effective Lagrangian
- quantum chromodynamics: radiative correction
- quark: operator
- nucleon: form factor
- cross section: scaling
- pi nucleon: interaction
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