학술논문

Deep exclusive electroproduction of $π^0$ at high $Q^2$ in the quark valence regime
Document Type
article
Source
Subject
hep-ex
nucl-ex
Language
Abstract
We report measurements of the exclusive neutral pion electroproduction crosssection off protons at large values of $x_B$ (0.36, 0.48 and 0.60) and $Q^2$(3.1 to 8.4 GeV$^2$) obtained from Jefferson Lab Hall A experiment E12-06-014.The corresponding structure functions $d\sigma_L/dt+\epsilon d\sigma_T/dt$,$d\sigma_{TT}/dt$, $d\sigma_{LT}/dt$ and $d\sigma_{LT'}/dt$ are extracted as afunction of the proton momentum transfer $t-t_{min}$. The results suggest theamplitude for transversely polarized virtual photons continues to dominate thecross-section throughout this kinematic range. The data are well described bycalculations based on transversity Generalized Parton Distributions coupled toa helicity flip Distribution Amplitude of the pion, thus providing a unique wayto probe the structure of the nucleon.