6533b827fe1ef96bd128676d
RESEARCH PRODUCT
The pion transition form factor and the pion distribution amplitude
Vicente VentoS. Noguerasubject
Nuclear and High Energy PhysicsParticle physicsDistribution (number theory)Scale (ratio)High Energy Physics::LatticeFOS: Physical sciencesPartonAstrophysics::Cosmology and Extragalactic Astrophysics01 natural sciencesPartícules (Física nuclear)PionHigh Energy Physics - Phenomenology (hep-ph)0103 physical sciencesTwist010306 general physicsNuclear ExperimentPhysicsQuantum chromodynamics010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyForm factor (quantum field theory)High Energy Physics - PhenomenologyAmplitudeFísica nuclearHigh Energy Physics::Experimentdescription
Recent BaBar data on the pion transition form factor, whose Q(2)-dependence is much steeper then predicted by asymptotic Quantum Chromodynamics (QCD), have caused a renewed interest in its theoretical description. We present here a formalism based on a model-independent description for low photon virtuality and a high photon virtuality description based on QCD, which match at a scale Q(0). The high photon virtuality description incorporates a flat pion distribution amplitude, phi(x) = 1, at the matching scale Q(0) and QCD evolution from Q(0) to Q > Q(0). The flat pion distribution is connected, through soft pion theorems and chiral symmetry, to the pion valence parton distribution at the same low scale Q(0). The procedure leads to a good description of the data, and by incorporating additional twist-three effects, to an excellent description of the data.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2010-01-18 |