Hard Exclusive Electroproduction of Pions ∗
نویسنده
چکیده
We investigate the exclusive electroproduction of π mesons from nucleons. To leading twist, leading order αs accuracy the corresponding production amplitude can be decomposed into pseudovector and pseudoscalar parts. Both can be expressed in terms of quark double distribution functions of the nucleon. While the pseudovector contribution is connected to ordinary polarized quark distributions, the pseudoscalar part can be related to one pion t-channel exchange. We observe that the pseudovector part of the production amplitude is important at xBj < 0.1. On the other hand, for 0.1 < xBj < 0.4 contributions from one pion exchange dominate. ∗Work supported in part by BMBF †Also Laboratory of Theoretical Physics, JINR, Dubna, Russian Federation
منابع مشابه
Hard Exclusive Electroproduction of Two Pions off Proton and Deuteron at HERMES
Exclusive electroproduction of π+π− pairs off hydrogen and deuterium targets has been studied with the HERMES experiment. The angular distribution of the π+ in the π+π− rest system has been studied in the invariant mass range 0.3 < mππ < 1.5 GeV. Theoretical models derived in the framework of the Generalized Parton Distributions show that this angular distribution receives only contributions fr...
متن کاملHard exclusive electroproduction of two pions and their resonances
We study the hard exclusive production of two pions in the virtual photon fragmentation region with various invariant masses including the resonance region. The amplitude is expressed in terms of two-pion light cone distribution amplitudes (2πDA’s). We derive dispersion relations for these amplitudes, which enables us to fix them completely in terms of ππ scattering phases and a few low-energy ...
متن کاملElectroproduction of pion pairs
We study hard exclusive electroproduction of two pions in the QCD factorization approach at next-to-leading order (NLO) in the strong coupling. The pion pair can be produced both in an isovector and in an isoscalar state. The angular distribution of the produced pion pairs allows one to project out a component that depends on the interference of the isovector and isoscalar channels. Using speci...
متن کاملExclusive channels in semi - inclusive production of pions and kaons
We investigate the role of exclusive channels in semi-inclusive electroproduction of pions and kaons. Using the QCD factorization theorem for hard exclusive processes we evaluate the cross sections for exclusive pseudoscalar and vector meson production in terms of generalized parton distributions and meson distribution amplitudes. We investigate the uncertainties arising from the modeling of th...
متن کاملINTERPLAY OF HARD AND SOFT PROCESSES AT JLAB ENERGIES ANDREI AFANASEV and CARL E. CARLSON
Even at moderate energy machines, there is a regime where hard pion electroproduction proceeds by a perturbatively calculable process. The process, we claim, is not the leading twist fragmentation one but rather a higher twist process that produces kinematically isolated pions. Semiexclusive data may teach us more about parton distribution functions of the target and the pion distribution ampli...
متن کامل