Hard exclusive electroproduction of two pions and their resonances
| dc.creator | Polyakov, M. V. | |
| dc.date | 1998-09-22 | |
| dc.date | 1999-03-20 | |
| dc.date.accessioned | 2026-07-07T10:33:44Z | |
| dc.date.available | 2026-07-07T10:33:44Z | |
| dc.description | 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 ($2π$DA'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 subtraction constants determind by the effective chiral lagrangian. Quantitative estimates of the resonance as well $ππ$ background DA's at low normalization point are made. We also prove certain new soft pion theorem relating two-pion DA's to the one-pion DA. Crossing relations between $2π$DA's and parton distributions in a pion are discussed. We demontrate that by studying the shape of the $ππ$ mass spectra (not absolute cross section!) in a diffractive electroproduction one can extract the deviation of the meson ($π,ρ,$ etc.) wave functions from their asymptotic form $6 z(1-z)$ and hence to get important information about the structure of mesons. Also we discuss how the moments of quark distributions in a pion can be measured in the hard diffraction. We suggest (alternative to Söding's) parametrization of $ππ$ spectra which is suitable for large photon virtuality. | |
| dc.description | 30 pages, one figure. Discussion of crossing relations between meson distribution amplitudes and quark densities is added | |
| dc.identifier | https://arxiv.org/abs/hep-ph/9809483 | |
| dc.identifier | http://arxiv.org/abs/hep-ph/9809483 | |
| dc.identifier | Nucl.Phys.B555:231,1999 | |
| dc.identifier | doi:10.1016/S0550-3213(99)00314-4 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/179223 | |
| dc.subject | High Energy Physics - Phenomenology | |
| dc.title | Hard exclusive electroproduction of two pions and their resonances | |
| dc.type | text |