The exclusive electroproduction of π+ mesons was studied with the HERMES spectrometer at the DESY laboratory by scattering 27.6 GeV positron and electron beams off an internal hydrogen gas target. The virtual-photon cross sections were measured as a function of the Mandelstam variable t and the squared four momentum −Q2 of the exchanged virtual photon. A model calculation based on Generalized Parton Distributions is in fair agreement with the data at low values of |t| if power corrections are included. A model calculation based on the Regge formalism gives a good description of the magnitude and the t and Q2 dependences of the cross section.
Cross sections for hard exclusive electroproduction of π+ mesons on a hydrogen target
BARION, Luca;CIULLO, Giuseppe;CONTALBRIGO, Marco;DALPIAZ, Pietro;LENISA, Paolo;PAPPALARDO, Luciano Libero;STATERA, Marco;
2008
Abstract
The exclusive electroproduction of π+ mesons was studied with the HERMES spectrometer at the DESY laboratory by scattering 27.6 GeV positron and electron beams off an internal hydrogen gas target. The virtual-photon cross sections were measured as a function of the Mandelstam variable t and the squared four momentum −Q2 of the exchanged virtual photon. A model calculation based on Generalized Parton Distributions is in fair agreement with the data at low values of |t| if power corrections are included. A model calculation based on the Regge formalism gives a good description of the magnitude and the t and Q2 dependences of the cross section.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
